Silybin mitigates chronic Avermectin exposure-induced intestinal damage and growth inhibition in carp

Avermectins, as a new type of environmental pollutant, have received significant attention in recent years. Previous research has shown that acute exposure to avermectins can induce oxidative stress and inflammation in non-target fish species, such as carp. Flavonoid lignans, particularly Silybin, have demonstrated promising biological activities, including regulation of non-alcoholic fatty liver and cerebral ischemia-reperfusion injury. This study aims to investigate the impact of dietary supplementation with Silybin on the intestinal damage in carp caused by chronic exposure to avermectins and to improve the health status and production of carp in aquaculture. Silybin was used as a dietary supplement by adding it to the experimental feed, and an animal experimental model was utilized to assess its effects on oxidative stress, inflammation, and cell apoptosis in carp intestine. Additionally, intestinal barrier integrity, digestive capacity, and fish growth were evaluated. The results indicated that dietary supplementation with Silybin effectively alleviated the oxidative stress induced by chronic exposure to avermectins in carp intestine. Furthermore, Silybin improved intestinal barrier integrity and digestive capacity by modulating the Nrf2/Keap1 pathway. This study demonstrates that dietary supplementation with Silybin can effectively mitigate the intestinal damage caused by chronic exposure to avermectins in carp, providing a sustainable solution for the aquaculture industry to enhance the overall health and production of cultured fish. The research expands our understanding of avermectin environmental pollution and offers a potential remediation approach.

Immunoprotective effect of silybin through blocking p53-driven caspase-9-Apaf-1-Cyt c complex formation and immune dysfunction after difenoconazole exposure in carp spleen

As a broad-spectrum and efficient triazole fungicide, difenoconazole is widely used, which not only pollutes the environment but also exerts toxic effects on non-target organisms. The spleen plays an important role in immune protection as an important secondary lymphoid organ in carp. In this study, we assessed the protective impact of silybin as a dietary additive on spleen tissues of carp during exposure to difenoconazole. Sixty carp were separated into four groups for this investigation including control group, difenoconazole group, silybin group, and silybin and difenoconazole group. By hematoxylin-eosin staining, dihydroethidium staining, immunohistochemical staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, quantitative real-time PCR assay, Western blot analysis, biochemical assays, and immune function indicator assays, we found that silybin could prevent difenoconazole-induced spleen tissue damage, oxidative stress, and immune dysfunction, and inhibited apoptosis of carp spleen tissue cells by suppressing the formation of p53-driven caspase-9-apoptotic protease activating factor-1-cytochrome C complex. The results suggested that silybin as a dietary additive could improve spleen tissue damage and immune dysfunction induced by difenoconazole in aquaculture carp.

Berberine-silybin salt achieves improved anti-nonalcoholic fatty liver disease effect through regulating lipid metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Berberine (BBR) and silybin (SIY) are natural compounds obtained from Berberidaceae members and Silybum marianum (L.) Gaertn., respectively. These compounds have been demonstrated to regulate lipid metabolism and indue hepatoprotective effects, establishing their importance for the treatment of liver injury. Combination therapy has shown promise in treating ailments with complex pathophysiology, such as liver diseases. However, the inconsistent dissolution and poor absorption of BBR and SIY limit their efficacy.

AIM OF THE STUDY

This study compared the salt formulation (BSS) and physical mixture (BSP) of BBR and SIY for their efficacy in treating nonalcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

The formation of the BSS was confirmed using various techniques, including nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, and powder X-ray diffractometry. In addition, dissolution, trans-epithelial permeability, and bioavailability experiments were conducted to evaluate the absorption and distribution of drugs. Pharmacodynamics and mechanisms were investigated through in vivo experiments.

RESULTS

BSS form demonstrated synchronized dissolution of both components, unlike BSP. Additionally, the transepithelial permeability results revealed that BSS exhibited superior penetration and absorption of both BBR and SIY in comparison to BSP. Furthermore, BSS significantly increased the bioavailability of SIY in both plasma and the liver (2.2- and 4.5-fold, respectively) when compared with BSP. Moreover, BSS demonstrated a more potent inhibitory effect on lipid production in HepG2 cells than BSP. In mouse models (BALB/c) of NAFLD, BSS improved disease outcomes, as evidenced by decreased adipose levels, normalized blood lipid levels, and reduced liver parenchyma injury. Preliminary transcriptomics analysis suggested that BSS achieved its anti-NAFLD effect by regulating the expression of fatty acid transporter CD36, recombinant fatty acid binding protein 4, and stearyl coenzyme A dehydrogenase 1, which are associated with the synthesis and uptake of fatty acid-related proteins.

CONCLUSIONS

The study demonstrated that compared with physical mixing, salification improved the efficacy of BBR and SIY, as demonstrated in animal experiments. These findings provide valuable insights into the development of more effective treatments for NAFLD and provide new possibilities for combination therapies.

Network Pharmacological Analysis and Experimental Validation of the Effects of Silybin on Proliferation, Migration, and Immunotherapy of Papillary Thyroid Cancer

AIM

The study aimed to use network pharmacology research and in vitro experiments to investigate the material basis and molecular mechanisms of silybin in the treatment of papillary thyroid carcinoma.

BACKGROUND

Papillary thyroid cancer (PTC) has a decent prognosis; however, recurrence and metastasis are the leading causes of death in patients with PTC. A key research focus in thyroid cancer treatment is the inhibition of PTC proliferation, invasion, and migration. Silybin, the major active element in the traditional Chinese herb silymarin, has been used to treat a range of diseases, including cancer, but no study has been undertaken to determine whether it can help prevent PTC.

OBJECTIVE

In this study, we attempted to determine through network pharmacology and in vitro experiments if silybin inhibits the development of papillary thyroid cancer by inhibiting cell cycle and invasive migration.

METHODS

To predict the probable targets and underlying mechanisms of silybin against PTC, a network pharmacology research was performed. In vitro experiments were conducted to further evaluate silybin's anti-cancer properties and priority targets against PTC.

RESULTS

The datasets revealed a total of 489 silybin targets acting on PTC, and functional enrichment analysis suggested that the target genes were enriched in functions and pathways related to PTC development, invasion, migration, and immunotherapy. By constructing these target PPI networks, the seven hub genes, fibronectin 1 (FN1), tissue inhibitor of metalloproteinases 1 (TIMP1), N-cadherin (CDH2), collagen type III alpha 1 chain (COL3A1), cyclin D1 (CCND1), AP-1 transcription factor subunit (JUN), and hepatocyte growth factor receptor (MET) were found. These hub genes were determined to be highly linked to a worse clinicopathological form, a higher risk of metastatic recurrence, and a worse prognosis of PTC. The common immunological checkpoint gene expression levels were positively correlated with the expression levels of the hub genes. Silybin decreased the proliferative and metastatic capacity of PTC cells, according to in vitro investigations. When PTC was treated with silybin, the FN1/AKT signaling pathway was blocked, CCND1 expression was reduced, and CDH2, Vimentin, Snail, Slug and PD-L1 expressions were dramatically reduced, while E-cadherin expression was significantly elevated.

CONCLUSION

These findings provide preliminary evidence that silybin inhibits PTC cell proliferation, metastasis, and invasion by altering the FN1/AKT signaling pathway and inhibiting the EMT process. Silybin can reverse immunosuppression in papillary thyroid cancer by affecting immunological checkpoint gene expression levels. These studies provide a theoretical and experimental scientific basis for the potential anticancer effects of silybin on PTC.

The role of miR-133a in silibinin-mediated inhibition of the PI3K/AKT/mTOR pathway in MCF-7 breast carcinoma cells

Breast cancer is particularly severe in women. Research highlights the crucial role of miRNAs in key cellular processes, showcasing their intricate interactions with the oncogenic PI3K/AKT/mTOR (PAM) signaling pathway and underscoring their significant role as tumor suppressors. The effect of silibinin on cell growth and survival was evaluated using an MTT assay. Bioinformatics analysis identified putative miR-133a targets inside the PAM pathway. After incubating MCF-7 cells with silibinin, we measured miR-133a, EGFR, PI3K, AKT, PTEN, and mTOR expression levels using qRT-PCR. Furthermore, protein expression levels of mTOR were assessed using Western blotting. The MTT experiment displayed that silibinin effectively inhibits MCF-7 cell proliferation in a time- and dose-dependent manner. Silibinin's IC50 value, determined at 370 μM after 48 hours, was established. qRT-PCR analysis at this IC50 concentration highlighted reduced expression of EGFR, PI3K, AKT, PTEN, and mTOR mRNAs, alongside increased miR-133a expression. Notably, miR-133a exhibited a negative correlation with both EGFR and PIK3C2A expression. Furthermore, western blotting confirmed silibinin's capacity to diminish p-mTOR protein levels, the ultimate element of the PAM signaling pathway. The findings enhance comprehension of silibinin's impact on PAM signaling and miR-133a expression, offering promise for targeted therapies in disrupting oncogenic pathways in MCF-7 breast cancer cells. This insight could advance breast cancer treatment strategies.

Bacterial butyrate mediates the anti-atherosclerotic effect of silybin

Silybin (SIL) is a versatile bioactive compound used for improving liver damage and lipid disorders and is also thought to be beneficial for atherosclerosis (AS). The goal of this study was to investigate the efficacy of SIL in the treatment of AS in ApoE-/-mice fed a high-fat diet and explore the mechanism underlying treatment outcomes. We found that SIL significantly alleviated AS-related parameters, including the extent of aortic plaque formation, hyperlipidemia, and adhesion molecule secretion in the vascular endothelium. 16 S rRNA gene sequencing analysis, together with the application of antibiotics, showed that intestinal butyrate-producing bacteria mediated the ameliorative effect of SIL on AS. Further analysis revealed that SIL facilitated butyrate production by increasing the level of butyryl-CoA: acetate CoA-transferase (BUT). The increased expression of monocarboxylic acid transporter-1 (MCT1) induced by butyrate and MCT4 induced by SIL in the apical and basolateral membranes of colonocytes, respectively, resulted in enhanced absorption of intestinal butyrate into the circulation, leading to the alleviation of arterial endothelium dysfunction. Moreover, the SIL-mediated increase in intestinal butyrate levels restored gut integrity by upregulating the expression of tight junction proteins and promoting gut immunity, thus inhibiting the AS-induced inflammatory response. This is the first study to show that SIL can alleviate AS by modulating the production of bacterial butyrate and its subsequent absorption.

Oral Administration of Silybin Protects Against MPTP-Induced Neurotoxicity by Reducing Pro-inflammatory Cytokines and Preserving BDNF Levels in Mice

Parkinson's disease (PD) is the second most frequent neurodegenerative disease associated with motor dysfunction secondary to the loss of dopaminergic neurons in the nigrostriatal axis. Actual therapy consists mainly of levodopa; however, its long-term use promotes secondary effects. Consequently, finding new therapeutic alternatives, such as neuroprotective molecules, is necessary. Among these alternatives is silybin (Sb), the major bioactive flavonolignan in silymarin. Both exert neuroprotective effects, preserving dopamine levels and dopaminergic neurons when administered in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse PD model, being probably Sb the potential therapeutic molecule behind this effect. To elucidate the role of Sb in the PD model, we determined the dose-dependent conservation of striatal dopamine content following Sb oral administration. Then, we evaluated motor deficit tests using the best dopamine conservative dose of Sb and determined a cytokine-dependent inflammatory profile status, malondialdehyde as an oxidative stress product, and neurotrophic factors content in the MPTP-induced mouse PD model. Our results show that oral Sb at 100 mg/kg dose conserved about 60% dopamine levels. Also, Sb improved motor deficits, preserved neurotrophic factors content and mitochondrial function, reduced lipid peroxidation, diminished proinflammatory cytokines to basal levels, enhanced fractalkine production in the striatum and substantia nigra, and increased IL-10 and IL-4 levels in the substantia nigra in the MPTP mice. Thus, oral Sb may be a potential pharmacological PD treatment alternative.

[Amatoxin-containing mushroom poisoning: An update]

Amatoxin-containing mushroom poisoning occurs after consumption of certain mushroom species, of the genera Amanita, Lepiota and Galerina. Amanita phalloides is the most implicated species, responsible for over more than 90% of mushroom-related deaths. The α-amanitin is responsible for most of the observed effects. Symptoms are characterized by severe delayed gastrointestinal disorders (more than six hours after ingestion). The liver being the main target organ, outcome is marked by an often severe hepatitis which can evolve towards terminal liver failure, justifying orthotopic liver transplantation. Acute renal failure is common. Diagnosis of amatoxin-containing mushroom poisoning is based primarily on clinical data; it can be biologically confirmed using detection of amatoxins, especially from urine samples. In the absence of an antidote, early hospital management is essential. It is based on supportive care (early compensation of hydroelectrolytic losses), gastrointestinal digestive decontamination, elimination enhancement, amatoxin uptake inhibitors and antioxidant therapy. Combined therapy associating silibinin and N-acetylcysteine is recommended. Prognosis of this severe poisoning has greatly benefited from improved resuscitation techniques. Mortality is currently less than 10%. In the event of a suspected or confirmed case, referral to a Poison Control Center is warranted in order to establish the diagnosis and guide the medical management of patients in an early and appropriate way.

Potential antibacterial and antioxidant inhibitory activities of Silybum marianum mediated biosynthesised He-Ne laser

A potentially beneficial method in laser irradiation is currently gaining popularity. The biosynthesis of low-power lasers has also been applied to the therapy of disease in biological tissues. This study used laser pre-treatments of Silybum marianum (S. marianum) fruit extract as a stabilising agent to bio-fabricate a low-power laser. The silybin A and silybin B of the S. marianum fruit, which are derived from seedlings before S. marianum undergoes therapy with an He-Ne laser at various intervals, were assessed for their expressive properties in this study. The findings revealed that 6-min laser pre-treatments increased silybin A + B and bacterial inhibition and improved the medicinal property of S. marianum. The analysis of the reaction records was performed using ultraviolet-visible spectroscopy. The minimum inhibitory concentration (MIC) limit for the sphere dispersion approach's antimicrobial effect on the microorganisms under investigation was 50 to 100 g/mL. With an IC50 of 0.69 mg/mL, the laser-treated S. marianum (6 min) demonstrated radical scavenging activity. At MIC concentration, the laser-treated S. marianum (6 min) did not exhibit cytotoxicity in the MCF-7 cell line. Additionally, Salmonella typhi, methicillin-resistant Staphylococcus aureus (MRSA), and E. coli were more susceptible to the antimicrobial effects of ethanolic fruit extract with a greater silybin level. It was observed that the laser-treated S. marianum (6 min) showed beneficial antioxidant and antibacterial properties and could be employed without risk in several medical applications.

Abamectin induced brain and liver toxicity in carp: The healing potential of silybin and potential molecular mechanisms

Abamectin (ABM) abuse contaminated aquatic environment and posed a potential threat to fish health as well as public safety. Silybin (SIL), a flavonoid, has been widely used as a novel feed additive to promote fish health. This research was to explore the potential antagonistic mechanism between ABM and SIL on brain and liver toxicity was investigated in common carp. Sixty carp were divided into four groups at random: the Control group, the SIL group, the ABM group, and ABM + SIL group. This experiment lasted for 30 d. According to behavioral observation, the detection of levels of acetylcholinesterase (AchE), iron, and mRNA expression levels of blood-brain barrier (BBB) related tight junction proteins (ZO-1, Claudin7, Occludin, MMP2, MMP9, and MMP13) in brain tissues, it was found that SIL relieved neurobehavioral disorders caused by ABM-induced BBB destruction in carp. H&E staining showed SIL mitigated nerve injury and liver injury caused by ABM. Oil Red O staining and liver-related parameters showed that SIL alleviated hepatotoxicity and lipid metabolism disorder caused by ABM exposure. Furthermore, this work also explored the specific molecular mechanism of SIL in liver protection and neuroprotection. It was shown that SIL lowered ROS levels in liver and brain tissues via the GSK-3β/TSC2/TOR pathway. Simultaneously, SIL inhibited NF-κB signaling pathway and played an anti-inflammatory role. In conclusion, we believed that SIL supplementation has a protective effect on the brain and liver by regulating oxidative stress and inflammation.

Ameliorative effects of silybin against avermectin-triggered carp spleen mitochondrial dysfunction and apoptosis through inhibition of PERK-ATF4-CHOP signaling pathway

The aim of this study was to investigate the splenic tissue damage of environmental biological drug avermectin to freshwater cultured carp and to evaluate the effect of silybin on the splenic tissue damage of carp induced by avermectin. A total of 60 carp were divided into 4 groups with 15 carp in each group, including the control group fed with basic diet, experimental group fed with basal diet and exposed to avermectin (avermectin group), experimental group fed with basal diet supplement silybin (silybin group), and experimental group fed with basal diet supplement silybin and exposed to avermectin (silybin + avermectin group). The whole test period lasted for 30 days, and spleen tissue was collected for analysis. In this study, H&E staining, mitochondrial purification and membrane potential detection, ATP detection, DHE staining, biochemical tests, qPCR, immunohistochemistry, and apoptosis staining were used to evaluate the biological processes of spleen tissue injury, mitochondrial function, oxidative stress, apoptosis, and endoplasmic reticulum stress. The results show that silybin protected carp splenic tissue damage caused by chronic avermectin exposure, decreased mitochondrial membrane potential, decreased ATP content, ROS accumulation, oxidative stress, apoptosis, and endoplasmic reticulum stress. Silybin may ameliorate the splenic tissue damage of cultured freshwater carp caused by environmental biopesticide avermectin by alleviating mitochondrial dysfunction and inhibiting PERK-ATF4-CHOP-driven mitochondrial apoptosis. Adding silybin into the diet becomes a feasible strategy to resist the pollution of avermectin and provides a theoretical basis for creating a good living environment for freshwater carp.

Silibinin alleviates inflammation-induced bone loss by modulating biological interaction between human gingival fibroblasts and monocytes

BACKGROUND

Silibinin has shown various pharmacological effects that could be attributed to its antioxidant, anti-inflammatory, and immunoregulatory properties. However, the therapeutic potential of silibinin for periodontitis has not been investigated.

METHODS

The therapeutic effects of silibinin in ligation-induced experimental periodontitis were investigated using biochemical, histological, and immunohistochemical methods. The effects of silibinin on the osteoclastogenesis of RAW264.7 cells were investigated using TRAP staining, quantitative polymerase chain reaction (qPCR), pit formation, and immunoblotting. Moreover, its effects on inflammatory cytokine production, RANKL expression, and oxidative stress in lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (HGFs) were evaluated using qPCR and flow cytometry. A coculture system was established to elucidate the effects of silibinin on the crosstalk between LPS-stimulated HGFs and undifferentiated monocytes.

RESULTS

Silibinin significantly reduced the alveolar bone loss, decreased the gingival inflammation and RANKL expression, and decreased the RANKL/osteoprotegerin ratio in gingival tissues in experimental periodontitis. The in vitro results showed that silibinin inhibited RANKL-induced osteoclast differentiation and function of RAW264.7 cells and suppressed RANKL-induced nuclear factor of activated T cells 1 (NFATc1) induction and translocation through the nuclear factor-κB and mitogen-activated protein kinase signaling pathways. Silibinin decreased the inflammatory cytokine level and oxidative stress production in LPS-stimulated HGFs; significantly suppressed membrane-bound RANKL expression on LPS-stimulated HGFs; and significantly disrupted TRAP+ cell differentiation in the coculture system.

CONCLUSIONS

Silibinin effectively inhibits inflammation-induced bone loss in experimental periodontitis based on the regulation of stimulated HGFs by inhibiting the expression of inflammatory and osteoclastogenic mediators. Collectively, targeting the inflamed HGF resolution that mediates osteogenesis may use silibinin as a potential drug-repurposing candidate for modulating alveolar bone destruction in periodontitis.

SUMMARY

Silibinin effectively inhibits inflammation-induced bone loss in experimental periodontitis based on the regulation of stimulated HGFs by inhibiting the expression of inflammatory and osteoclastogenic mediators.

Polyunsaturated fatty acids drive neutrophil extracellular trap formation in nonalcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome. Non-resolving inflammation, triggered by sustained accumulation of lipids, is an important driving force of NASH. Thus, unveiling metabolic immune regulation could help better understand the pathology and intervention of NASH. In this study, we found the recruitment of neutrophils is an early inflammatory event in NASH mice, following the formation of neutrophil extracellular traps (NETs). NET is an initiating factor which exacerbates inflammatory responses in macrophages. Inhibition of NETs using DNase I significantly alleviated inflammation in NASH mice. We further carried out a metabolomic study to identify possible metabolic triggers of NETs, and linoleic acid (LA) metabolic pathway was the most altered pathway. We re-analyzed published clinical data and validated that LA metabolism was highly correlated with NASH. Consistently, both LA and γ-linolenic acid (GLA) were active in triggering NETs formation by oxidative burst. Furthermore, we identified silybin, a hepatoprotective agent, as a potent NETosis inhibitor, which effectively blocked NETs formation both in vitro and in vivo. Together, this study not only provide new insights into metabolism-immune causal link in NASH progression, but also demonstrate silybin as an important inhibitor of NETs and its therapeutical potential in treating NETosis-related diseases.

Topical treatment of tea saponin stabilized silybin nanocrystal gel reduced oxidative stress in UV-induced skin damage

UV-induced peroxidation is a significant factor in skin damage. Some natural products have been utilized to protect the skin. However, most of them suffer from issues such as poor bioavailability. A promising strategy is to prepare them as safe and convenient gels. In this study, we constructed Silybin Nanocrystal Gel (SIL-NG). Tea saponin, a spatial stabilizer that we have previously reported, was used to prepare SIL-NS and subsequently combined with xanthan gum to prepare SIL-NG with an excellent safety profile. This nanogel with a natural stabilizer has a suitable ductility and shows a good safety profile in vitro and in vivo. In L929 cells, SIL-NG was able to reduce H₂O₂-induced ROS levels. In addition, SIL-NG exhibited better antioxidant activity compared to SIL-NS. SIL-NG was able to reduce UVB irradiation-induced oxidative damage in mice, significantly increase SOD activity, and reduce MDA levels. In conclusion, our work gives a new perspective on the treatment of UV skin damage using natural ingredients.

Silybin regulates P450s activity by attenuating endoplasmic reticulum stress in mouse nonalcoholic fatty liver disease

Cytochrome P450s are important phase I metabolic enzymes located on endoplasmic reticulum (ER) involved in the metabolism of endogenous and exogenous substances. Our previous study showed that a hepatoprotective agent silybin restored CYP3A expression in mouse nonalcoholic fatty liver disease (NAFLD). In this study we investigated how silybin regulated P450s activity during NAFLD. C57BL/6 mice were fed a high-fat-diet (HFD) for 8 weeks to induce NAFLD, and were administered silybin (50, 100 mg ·kg^-1 ·d^-1, i.g.) in the last 4 weeks. We showed that HFD intake induced hepatic steatosis and ER stress, leading to significant inhibition on the activity of five primary P450s including CYP1A2, CYP2B6, CYP2C19, CYP2D6, and CYP3A in liver microsomes. These changes were dose-dependently reversed by silybin administration. The beneficial effects of silybin were also observed in TG-stimulated HepG2 cells in vitro. To clarify the underlying mechanism, we examined the components involved in the P450 catalytic system, membrane phospholipids and ER membrane fluidity, and found that cytochrome b5 (cyt b5) was significantly downregulated during ER stress, and ER membrane fluidity was also reduced evidenced by DPH polarization and lower polyunsaturated phospholipids levels. The increased ratios of NADP⁺/NADPH and PC/PE implied Ca²⁺ release and disruption of cellular Ca²⁺ homeostasis resulted from mitochondria dysfunction and cytochrome c (cyt c) release. The interaction between cyt c and cyt b5 under ER stress was an important reason for P450s activity inhibition. The effect of silybin throughout the whole course suggested that it regulated P450s activity through its anti-ER stress effect in NAFLD. Our results suggest that ER stress may be crucial for the inhibition of P450s activity in mouse NAFLD and silybin regulates P450s activity by attenuating ER stress.

Synergistic effects of silybin and curcumin on virulence and carbapenemase genes expression in multidrug resistant Klebsiella oxytoca

OBJECTIVE

Silybin and curcumin have potential antimicrobial effects. This study aimed to evaluate the synergistic antimicrobial effects of silybin and curcumin on virulence and carbapenemase genes expression among multidrug-resistant (MDR) Klebsiella oxytoca.

RESULTS

A total of 70 MDR K. oxytoca (carrying bla_IMP and bla_OXA-48-like genes) were included. The antibiotic susceptibility and biofilm production of isolates were determined. The silybin and curcumin at concentrations 10-500 mg/mL alone and in combination were exposed to bacterial isolates in Mueller Hinton broth medium for 24 h. The expression of bla_IMP, bla_OXA-48-like, mrkA, pilQ, matB and fimA genes was evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). The mean minimum inhibitory concentration (MIC) of curcumin and silybin were 250 mg/mL and 500 mg/mL, respectively. The anti-virulent effect of 100 mg/mL of silybin and curcumin was shown by significant reduction in the expression of fimA (2.1-fold, P < 0.0001) and mrkA (2.1 fold, P < 0.0001) genes. Moreover, these compounds significantly decreased the expression of bla_IMP1 (3.2-fold, P < 0.0001) gene. Notably, there was no significant effect on pilQ, matB and bla_OXA-48-like genes. The results showed that silybin and curcumin can be candidate as natural way for control the MDR virulent strains of K. oxytoca.

Silibinin Radiosensitizes EGF Receptor-knockdown Prostate Cancer Cells by Attenuating DNA Repair Pathways

Emergence of radioresistance in prostate cancer (PCa) cells is a major obstacle in cancer therapy and contributes to the relapse of the disease. EGF receptor (EGFR) signaling plays an important role in the development of radioresistance. Herein, we have assessed the modulatory effects of silibinin on radiation-induced resistance via DNA repair pathways in EGFR-knockdown DU145 cells. shRNA-based silencing of EGFR was done in radioresistant human PCa DU145 cells and effects of ionizing radiation (IR) and silibinin were assessed using clonogenic and trypan blue assays. Furthermore, radiosensitizing effects of silibinin on PCa in context with EGFR were analyzed using flow cytometry, comet assay, and immunoblotting. Silibinin decreased the colony formation ability with an increased death of DU145 cells exposed to IR (5 Gray), with a concomitant decrease in Rad51 protein expression. Silibinin (25 μM) augmented the IR-induced cytotoxic effect in EGFR-knockdown PCa cells, along with induction of G2/M phase cell cycle arrest. Further, we studied homologous recombination (HR) and non-homologous end joining (NHEJ) pathways in silibinin-induced DNA double-strand breaks in EGFR-knockdown DU145 cells. Silibinin down-regulated the expression of Rad51 and DNA-dependent protein kinase proteins without any considerable effect on Ku70 and Ku80 in IR-exposed EGFR-knockdown PCa cells. The pro-survival signaling proteins, phospho-extracellular signal-regulated kinases (ERK)1/2, phospho-Akt and phospho-STAT3 were decreased by silibinin in EGFR-deficient PCa cells. These findings suggest a novel mechanism of silibinin-induced radiosensitization of PCa cells by targeting DNA repair pathways, HR and NHEJ, and suppressing the pro-survival signaling pathways, ERK1/2, Akt and STAT3, in EGFR-knockdown PCa cells.

Silybin induces endothelium-dependent vasodilation via TRPV4 channels in mouse mesenteric arteries

Silybin is a flavonolignan extracted from the seeds of Silybum marianum that has been used as a dietary supplement for treating hepatic diseases and components of metabolic syndrome such as diabetes, obesity and hypertension. Transient receptor potential vanilloid 4 (TRPV4) channels are Ca²⁺-permeable, nonselective cation channels that regulate vascular endothelial function and blood flow. However, the relationship between silybin and TRPV4 channels in small mesenteric arteries remains unknown. In our study, we carried out a molecular docking experiment by using Discovery Studio v3.5 to predict the binding of silybin to TRPV4. Activation of TRPV4 with silybin was detected via intracellular Ca²⁺ concentration ([Ca²⁺]_i) measurement and patch clamp experiments. The molecular docking results showed that silybin was likely to bind to the ankyrin repeat domain of TPRV4. [Ca²⁺]_i measurements in mesenteric arterial endothelial cells (MAECs) and TRPV4-overexpressing HEK293 (TRPV4-HEK293) cells demonstrated that silybin induced Ca²⁺ influx by activating TRPV4 channels. The patch clamp experiments indicated that in TRPV4-HEK293 cells, silybin induced TRPV4-mediated cation currents. In addition, in high-salt-induced hypertensive mice, oral administration of silybin decreased systolic blood pressure (SBP) and significantly improved the arterial dilatory response to acetylcholine. Our findings provide the first evidence that silybin could induce mesenteric endothelium-dependent vasodilation and reduce blood pressure in high-salt-induced hypertensive mice via TRPV4 channels, thereby revealing the potential effect of silybin on preventing endothelial dysfunction-related cardiovascular diseases.

Prebiotic-like cyclodextrin assisted silybin on NAFLD through restoring liver and gut homeostasis

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease with no currently approved treatment. The natural compound silybin (SLN) has versatile hepatoprotective efficacy with negligible adverse effects; however, poor absorption limits its clinical applications. Gut microbiota has been proposed to play a crucial role in the pathophysiology of NAFLD and targeted for disease control. Cyclodextrins, the cyclic oligosaccharides, were documented to have various health benefits with potential prebiotic properties. This study aimed to develop a silybin-2-hydroxypropyl-β-cyclodextrin inclusion (SHβCD) to improve the therapeutic efficacy of SLN and elucidate the mechanisms of improvement. The results showed that SLN formed a 1:1 stoichiometric inclusion complex with HP-β-CD. The solubility of SLN was increased by generating SHβCD, resulting in improved drug permeability and bioavailability. In high-fat diet (HFD)-fed hamsters, SHβCD modulated gut health by restoring the gut microbiota and intestinal integrity. SHβCD showed superior anti-lipid accumulation, antioxidant, and anti-inflammatory effects compared with SLN alone. Transcriptome analysis in the liver tissue implied that the improved inflammation and/or energy homeostasis was the potential mechanism. Therefore, SHβCD may be a promising alternative for the treatment of NAFLD, attributing to the dual functions of HβCD on drug absorption and gut microbial homeostasis.

Flavonolignans from silymarin modulate antibiotic resistance and virulence in Staphylococcus aureus

Antibiotic resistance is currently a serious health problem. Since the discovery of new antibiotics no longer seems to be a sufficient tool in the fight against multidrug-resistant infections, adjuvant (combination) therapy is gaining in importance as well as reducing bacterial virulence. Silymarin is a complex of flavonoids and flavonolignans known for its broad spectrum of biological activities, including its ability to modulate drug resistance in cancer. This work aimed to test eleven, optically pure silymarin flavonolignans for their ability to reverse the multidrug resistance phenotype of Staphylococcus aureus and reduce its virulence. Silybin A, 2,3-dehydrosilybin B, and 2,3-dehydrosilybin AB completely reversed antibiotic resistance at concentrations of 20 µM or less. Both 2,3-dehydrosilybin B and AB decreased the antibiotic-induced gene expression of representative efflux pumps belonging to the major facilitator (MFS), multidrug and toxic compound extrusion (MATE), and ATP-binding cassette (ABC) families. 2,3-Dehydrosilybin B also inhibited ethidium bromide accumulation and efflux in a clinical isolate whose NorA and MdeA overproduction was induced by antibiotics. Most of the tested flavonolignans reduced cell-to-cell communication on a tetrahydrofuran-borate (autoinducer-2) basis, with isosilychristin leading the way followed by 2,3-dehydrosilybin A and AB, which halved communication at 10 µM. Anhydrosilychristin was the only compound that reduced communication based on acyl-homoserine lactone (autoinducer 1), with an IC₅₀ of 4.8 µM. Except for isosilychristin and anhydrosilychristin, all of the flavonolignans inhibited S. aureus surface colonization, with 2,3-dehydrosilybin A being the most active (IC₅₀ 10.6 µM). In conclusion, the selected flavonolignans, particularly derivatives of 2,3-dehydrosilybin B, 2,3-dehydrosilybin AB, and silybin A are non-toxic modulators of S. aureus multidrug resistance and can decrease the virulence of the bacterium, which deserves further detailed research.

Silybin B exerts protective effect on cisplatin-induced neurotoxicity by alleviating DNA damage and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Silybum marianum is a traditional Chinese medicine that has been used for treating liver disease. Silybin consisting of silybin A and silybin B, is a member of Silybum marianum, and exerts a therapeutic effect on many diseases. However, the protective effect of silybin on cisplatin-induced neurotoxicity and the stereoisomer contributing to the effect remain unknown.

AIM OF THE STUDY

The present study aimed to study the effect of silybin on cisplatin-induced neuronal injury, compare the difference of protective effect between silybin A and silybin B, and the potential mechanism.

MATERIALS AND METHODS

High performance liquid chromatography (HPLC) was used to separate silybin A and silybin B. X-ray crystallographic analysis in combination with experimental and calculated ECD were performed to identify the structure of silybin A and silybin B. The toxicity of the silybin or cisplatin against murine hippocampal neuronal HT22 cells was determined through MTT assay. The cell cycle and cell apoptosis were measured by PI staining and Annexin V-FITC/PI staining, respectively, and then subjected to flow cytometry. Western blot analysis was conducted to quantify the expression of proteins related to apoptosis and DNA damage. Immunofluorescence was used to evaluate the expression of DNA damage marker. In vivo experiment, the behavioral analysis was determined through pole test, swimming test and Morris water maze test. The index of superoxide dismutase (SOD), reduced glutathione (GSH), total antioxidant capacity (T-AOC) and lipid peroxidation (LPO) were examined to evaluate the antioxidant capacity in mice brain. Nissl staining and Tunel assay were used to detect the neuronal viability and apoptosis in hippocampus.

RESULTS

We successfully separated and identified silybin A and silybin B. We found both silybin A and silybin B alleviated cisplatin-induced apoptosis and cell cycle arrest in HT22 cells, and silybin B was more effective. We chose silybin B for further mechanism investigation, and found silybin B alleviated DNA damage by enhancing phosphorylation of ATR and decreasing expression of γ-H2AX. In the in vivo experiment, we observed that silybin B markedly improved the behavioral abnormalities in cisplatin-treated mice, reduced LPO level while increased SOD, GSH and T-AOC in mice brain tissue. Nissl staining and Tunel assay showed that silybin B alleviated cisplatin-induced hippocampal damage.

CONCLUSIONS

These results suggest that silybin B might serve as a promising drug candidate in mitigating cisplatin-induced neural injury in the brain and thereby improving the chemotherapeutic outcomes.

Neferine increases sensitivities to multiple anticancer drugs via downregulation of Bcl-2 expression in renal cancer cells

BACKGROUND

Neferine is the major alkaloid extracted from a seed embryo of Nelumbo nucifera and shows cytotoxic effects in various human cancer cells. However, no detailed studies have been reported on its antitumor efficacy of a combinational treatment in human renal cancer cells.

OBJECTIVE

This study evaluated the antitumor effects of a combination therapy of neferine and various drugs on renal cancer Caki-1 cells.

METHODS

Flow cytometry analysis was performed to evaluate the cell cycle analysis and apoptosis, respectively. Western blotting and reverse transcription polymerase chain reaction were performed to analyze the effect of neferine on the expression of apoptosis-related genes in Caki-1 cells. In addition, reactive oxygen species (ROS) generation was evaluated using flow cytometry.

RESULTS

Treatment with neferine dose-dependently induces apoptosis and Bcl-2 downregulation in Caki-1 cells. In addition, neferine triggers cell cycle arrest at the G2/M phase in Caki-1 cells. The neferine-induced apoptosis was mediated by ROS generation, and neferine-facilitated Bcl-2 downregulation was regulated at the transcriptional level through the suppression of p65 expression, resulting in inactivation of the NF-κB pathway in Caki-1 cells. The ROS scavenger, N-acetyl-l-cysteine (NAC), intensely reversed the effects of neferine on apoptosis and Bcl-2 downregulation. We determined that neferine markedly potentiates the antitumor effects of multiple anticancer drugs (cisplatin, silybin, and thapsigargin), and those effects can be reversed by Bcl-2 overexpression or NAC pretreatment in Caki-1 cells.

CONCLUSION

These results suggest that neferine can increase chemosensitivities to anticancer drugs via downregulation of Bcl-2 expression through ROS-dependent suppression of the NF-κB signaling pathway in human renal cancer cells.

Investigation on the solid-phase synthesis of silybin prodrugs and their timed-release

Prodrugs are ingenious derivatives of therapeutic agents designed to improve the pharmacokinetic profile of the drug. Here, we report an efficient and regioselective solid phase approach for obtaining new prodrugs of 9″-silybins conjugated with 3'-ribonucleotide units (uridine and adenosine) as pro-moieties. Uridine and adenosine conjugates were obtained in good yields (41-50%), beginning with silibinin and its diastereomers (silybin A and silybin B), using a NovaSyn® support functionalized with an ad hoc linker, which allowed selective detachment of only the desired products. As expected, the solubility of both uridine and adenosine conjugates was higher than that of the parental natural product (5 mg/mL and 3 mg/mL for uridine and adenosine, respectively). Our investigations revealed that uridine conjugates were quickly cleaved by RNase A, releasing silybin drugs, even at low enzyme concentrations. No toxic effects were found for any ribonucleotide conjugate on differentiated neuroblastoma SH-SY5Y cells when tested at increasing concentrations. All results strongly encourage further investigations of uridine-silybin prodrugs as potential therapeutic agents for both oral and intravenous administration. The present synthetic approach represents a valuable strategy to the future design of new prodrugs with modified nucleoside pro-moieties to modulate the pharmacokinetics of silybins or different natural products with strong pharmacological activities but poor bioavailability.

pH-Sensitive PEGylated Liposomal Silybin: Synthesis, In Vitro and In Vivo Anti-Tumor Evaluation

The drug delivery systems improve the efficacy of chemotherapeutics through enhanced targeting and controlled release however, biological barriers of tumor microenvironment greatly impede the penetration of nanomedicine within the tumor. We report herein the fabrication of a PEG-detachable silybin (SLB) pH-sensitive liposome decorated with TAT-peptide. For this, Acyl hydrazide-activated PEG₂₀₀₀ was prepared and linked with ketone-derivatized DPPE via an acid-labile hydrazone bond to form mPEG₂₀₀₀-HZ-DPPE. TAT peptide was conjugated with a shorter -PEG₁₀₀₀-DSPE spacer and post-inserted into PEGylated liposome (DPPC: mPEG₂₀₀₀-DSPE: Chol). To prepare nanoliposomes (around 100 nm), first, a novel method was used to prepare SLB-Soya PC (SLB-SPC) complex, then this complex was incorporated into nanoliposomes. The pH-sensitivity and shielding effect of long PEG chain on TAT peptide was investigated using DiI liposome and FACS analysis. Pre-treatment to the lowered pH enhanced cellular association of TAT-modified pH-sensitive liposome due to the cleavage of hydrazone bond and TAT exposure. Besides, TAT-modified pH-sensitive liposomes significantly reduced cell viability compared to the plain liposome. In vivo results were very promising with pH-sensitive liposome by detaching PEG moieties upon exposure to the acidic tumor microenvironment, enhancing cellular uptake, retarding tumor growth, and prolonging the survival of 4T1 breast tumor-bearing BALB/c mice. TAT modification of pH-sensitive liposome improved cancer cell association and cytotoxicity and demonstrated potential intracellular delivery upon exposure to acidic pH. However, in in vivo studies, TAT as a targeting ligand significantly decreased the therapeutic efficacy of the formulation attributed to an inefficient tumor accumulation and higher release rate in the circulation. The results of this study indicated that pH-sensitive liposome containing SLB, which was prepared with a novel method with a significant SLB loading efficiency, is very effective in the treatment of 4T1 breast tumor-bearing BALB/c mice and merits further investigation.

Structural Modification of Sylibin to Derivatives of Sylibin/Hydnocarpin D /Silandrin, and Evaluation of Their Cytotoxicity Against Cancer Cells

BACKGROUND

Flavonolignans like silybin, hydnocarpin, and siliandrin are a group of natural compounds combining the structural moieties of flavonoid and phenylpropanoid (lignan). Hydnocarpin and silandrin were less explored because of trace occurrence in nature.

OBJECTIVE

The present study aimed to develop a chemical conversion of silybin to hydnocarpin, and siliandrin. Also, a series of amide derivatives would be synthesized and biologically evaluated with regard to their anti-cancer effects.

METHODS

In order to selectively convert silybin to 23-iodo silybin, 23-iodo hydnocarpin D and 23-iodo isosilandrin, the ratio of Ph3P, imidazole and molecular iodine was meticulously adjusted. These three iodide compounds were converted into amide compounds by chemical transformation. MTT method was applied to evaluate their anti-cancer potency. The binding affinity to related proteins was calculated by molecular docking.

RESULTS

Totally, 45 new amido-derivatives were synthesized and structurally characterized by NMR and HRMS. Some of them showed moderate to good antiproliferative potency against cancer cells. The activity of compound 10j was further testified by colony formation assay and molecular docking.

CONCLUSION

Synthesis of 23-iodo silybin, 23-iodo hydnocarpin D and 23-iodo isosilandrin from silybin was successfully accomplished by one simple iodination reaction. Some of the amide derivatives of sylibin/hydnocarpin D /silandrin exhibit a remarkable inhibitory effect of proliferation on cancer cells as compared to silybin. These results would pave the way for further investigation on the derivatives of flavonolignans for the treatment of cancer.

Silybin alleviates hepatic lipid accumulation in methionine-choline deficient diet-induced nonalcoholic fatty liver disease in mice via peroxisome proliferator-activated receptor α

Nonalcoholic fatty liver disease (NAFLD) is regarded as the most common liver disease with no approved therapeutic drug currently. Silymarin, an extract from the seeds of Silybum marianum, has been used for centuries for the treatment of various liver diseases. Although the hepatoprotective effect of silybin against NAFLD is widely accepted, the underlying mechanism and therapeutic target remain unclear. In this study, NAFLD mice caused by methionine-choline deficient (MCD) diet were orally administrated with silybin to explore the possible mechanism and target. To clarify the contribution of peroxisome proliferator-activated receptor α (PPARα), PPARα antagonist GW6471 was co-administrated with silybin to NAFLD mice. Since silybin was proven as a PPARα partial agonist, the combined effect of silybin with PPARα agonist, fenofibrate, was then evaluated in NAFLD mice. Serum and liver samples were collected to analyze the pharmacological efficacy and expression of PPARα and its targets. As expected, silybin significantly protected mice from MCD-induced NAFLD. Furthermore, silybin reduced lipid accumulation via activating PPARα, inducing the expression of liver cytosolic fatty acid-binding protein, carnitine palmitoyltransferase (Cpt)-1a, Cpt-2, medium chain acyl-CoA dehydrogenase and stearoyl-CoA desaturase-1, and suppressing fatty acid synthase and acetyl-CoA carboxylase α. GW6471 abolished the effect of silybin on PPARα signal and hepatoprotective effect against NAFLD. Moreover, as a partial agonist for PPARα, silybin impaired the powerful lipid-lowering effect of fenofibrate when used together. Taken together, silybin protected mice against NAFLD via activating PPARα to diminish lipid accumulation and it is not suggested to simultaneously take silybin and classical PPARα agonists for NAFLD therapy.

Enhancing TNBC Chemo-immunotherapy via combination reprogramming tumor immune microenvironment with Immunogenic Cell Death

Tumor-associated fibroblasts (TAFs) play an important role in tumor progression and therapeutic response, especially in the immunosuppressive tumor microenvironment (TME). To remodel immunosuppressive TME of 4T1 tumor, we developed a nano liposome to deliver silybin (SLN, an anti-liver fibrosis Chinese Traditional Medicine). Liposomal silybin (SLN/LIP) possessed a spherical shape with particle sizes of 75.2 nm, high stability, and good accumulation in the tumor site. After treated with SLN/LIP, α-SMA positive TAFs and the deposition of stroma were decreased significantly. SLN/LIP also changed the tumor immune microenvironment through the increase of IFN-γ and IL-12, as well as reduced of TGF-β, SDF-1, IL6 and TNF-α. Importantly, SLN/LIP enhanced the infiltration of cytotoxic T cells (CTLs) and transformed a "cold" tumor into a "hot" tumor. To achieve the higher antitumor efficacy, an immunogenic cell death (ICD) inducer, liposomal doxorubicin (DOX/LIP) was combined with SLN/LIP. The combination treatment led to trigger immunogenic tumor apoptosis, and enhance antitumor immunity, therefore, improved anti-tumor efficiency, and further prolonged survival duration. The combination of liposomal silybin and liposomal doxorubicin might be a new chemo-immunotherapy approach for triple negative breast cancer (TNBC) tumor treatment.

Suppression of up-regulated LXRα by silybin ameliorates experimental rheumatoid arthritis and abnormal lipid metabolism

BACKGROUND

As dysregulation of immunometabolism plays a key role in the immunological diseases, dyslipidemia frequently observed in rheumatoid arthritis (RA) patients (60%) is associated with the disease activity and has been considered as the potential target of anti-inflammatory strategy. However, targeting of metabolic events to develop novel anti-inflammatory therapeutics are far from clear as well as the mechanism of dyslipidemia in RA.

PURPOSE

To explore the therapeutic potential and mechanisms of silybin again RA through the regulation of lipid metabolism.

METHODS

Adjuvant-induced arthritis (AIA) rat model was used to examine the effects of silybin on modulating dysregulated lipid metabolism and arthritis. Metabolomics, docking technology, and biochemical methods such as western blots, qRT-PCR, immunofluorescence staining were performed to understanding the underlying mechanisms. Moreover, knock-down of LXRα and LXRα agonist were used on LO2 cell lines to understand the action of silybin.

RESULTS

We are the first to demonstrate that silybin can ameliorate dyslipidemia and arthritis in AIA rats. Overexpression of LXRα and several key lipogenic enzymes regulated by LXRα, including lipoprotein lipase (LPL), cholesterol 7α and 27α hydroxylase (CYP7A, CYP27A), adipocyte fatty acid-binding protein (aP2/FABP4) and fatty acid translocase (CD36/FAT), were observed in AIA rats, which mostly accounted for dyslipidemia during arthritis development. Metabolomics, docking technology, and biochemical results indicated that anti-arthritis effects of silybin related to suppressing the up-regulated LXRα and abnormal lipid metabolism. Notably, activation of LXRα could potentiate cell inflammatory process induced by LPS through the regulation of NF-κB pathway, however, suppression of LXRα agonism by siRNA or silybin reduced the nuclear translocation of NF-κB as well as the induction of downstream cytokines, indicating LXRα agonism is the important factor for the arthritis development and could be a potential target.

CONCLUSION

The up-regulation of LXRα can activate lipogenesis enzymes to worsen the inflammatory process in AIA rats as well as the development of dyslipidemia, therefore, rectifying lipid disorder via suppression of LXRα agonism pertains the capacity of drug target, which enables to discover and develop new drugs to treat rheumatoid arthritis with dyslipidaemia.

Mucoadhesive nanocrystal-in-microspheres with high drug loading capacity for bioavailability enhancement of silybin

Nanocrystals, due to high drug loading efficiency, have drawn large attention as nanotechnology to enhance solubility and bioavailability of poorly soluble drugs. However, most nanocrystals still encountered low oral absorption percentage due to its insufficient retention time in the gastrointestinal tract (GI). In this work, silybin (SB) as model drug was fabricated to nanocrystals, and further loaded into a mucoadhesive microsphere to increase the GI retention. Such mucoadhesive microspheres were prepared with a wet media milling technique followed by coagulation and film coating. Nanocrystals and microspheres were thoroughly characterized by diverse complementary techniques. As results, such delivery system displayed an encapsulation efficiency of approximately 100 % and a drug loading capacity of up to 35.41 ± 0.31 %. In addition, mucoadhesiveness test ex vivo conducted with rat intestine showed that film-coated microspheres were retained for more than 1 h. Benefiting from nanocrystals technology, the drug cumulative release percentage of the microspheres was remarkable improved compared to unprocessed one in vitro. Finally, pharmacokinetics studies in rats showed a significant 3-fold increase of drug oral bioavailability compared to unprocessed SB. The current study demonstrates that the developed delivery vehicle can enhance the bioavailability of SB by increasing its dissolution percentage as well as through extending retention time in the GI tract, and achieve high drug loading capacity.

Co-delivery of silybin and paclitaxel by dextran-based nanoparticles for effective anti-tumor treatment through chemotherapy sensitization and microenvironment modulation

Modulation of tumor microenvironment (TME) has been indicated as an approach to improve efficacy of cancer therapy. Here, we proposed a nano co-delivery based combination therapy of paclitaxel (PTX) and silybin (SB) which can employ the synergistic effects through chemotherapy sensitization and microenvironment modulation. A dextran-based amphiphilic polymer (Dex-DOCA) was successfully developed for in vivo co-delivery and thus "synchronizing" the biodistribution, transport and release of PTX and SB. Resultantly, Dex-DOCA exhibited an excellent encapsulating efficiency for both PTX and SB with adjustable loading ratio for an optimal synergistic antitumor activity. Moreover, the co-loaded nanoparticles efficiently discharged the two drugs at the prospective dosage ratio specifically in acid endo/lysosome mimic environments. The results of in vitro cytotoxicity and cell apoptosis assays further confirmed the SB sensitized PTX potency. Finally, in vivo investigation demonstrated that the co-loaded nanoparticles could effectively accumulate in tumor sites by passive targeting, and inhibit tumor growth through an enhanced intratumoral penetration (resulted from stromal components eradication and tumor vessels normalization associated TME modulation), as well as a sensitization effect of SB on PTX cytotoxic chemotherapy.

Green production of silybin and isosilybin by merging metabolic engineering approaches and enzymatic catalysis

Silymarin extracted from milk thistle seeds, is used for treating hepatic diseases. Silybin and isosilybin are its main components, and synthesized from coupling of taxifolin and coniferyl alcohol. Here, the biosynthetic pathways of taxifolin and coniferyl alcohol were reconstructed in Saccharomyces cerevisiae for the first time. To alleviate substantial burden caused by a great deal of genetic manipulation, expression of the enzymes (e.g. ZWF1, TYR1 and ARO8) playing multiple roles in the relevant biosynthetic pathways was selectively optimized. The strain YT1035 overexpressing seven heterologous enzymes and five native enzymes and the strain YC1053 overexpressing seven heterologous enzymes and four native enzymes, respectively produce 336.8 mg/L taxifolin and 201.1 mg/L coniferyl alcohol. Silybin and isosilybin are synthesized from taxifolin and coniferyl alcohol under catalysis of APX1t (the truncated milk thistle peroxidase), with a yield of 62.5%. This study demonstrates an approach for producing silybin and isosilybin from glucose for the first time.

Phytosome-nanosuspensions for silybin-phospholipid complex with increased bioavailability and hepatoprotection efficacy

Silybin, a natural compound for treating liver disease, has been shown to provide diverse biological activities such as anticancer, antioxidant and hepatoprotective. However, it is still challenging to develop silybin product due to its poor aqueous solubility and limited gastrointestinal absorption. In order to improve the low bioavailability of silybin, a novel formulation of phytosome-nanosuspensions for silybin shielding termed as SPCs-NPs, has been developed herein for hepatoprotection efficacy. We found that SPCs-NPs formulation not only possessed an increased in vitro dissolution rate but also improved plasma concentration in the in vivo pharmacokinetic study. Moreover, SPCs-NPs was provided with more potent hepatoprotective effects in pharmacodynamic assessments. Moreover, physicochemical features including interactions between silybin and phospholipid, and crystalline variation of the optimized SPCs-NPs formulation were confirmed by using Fourier-transform infrared spectrometry (FTIR), ¹H nuclear magnetic resonance spectroscopy (H-NMR), differential scanning calorimetry (DSC), and powder X-ray diffraction spectroscopy (PXRD) respectively. Overall, the interesting finding of this study suggested that SPCs-NPs could be applied as a promising formulation for a higher drug bioavailability and better hepatoprotection efficacy.

THE EFFECTS OF REALSIL (SILYBIN-PHOSPHOLIPID-VITAMIN E COMPLEX) ON LIVER ENZYMES IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD) OR NON-ALCOHOLIC STEATO-HEPATITIS (NASH): A SYSTEMATIC REVIEW AND META-ANALYSIS OF RCTS

Background

The aim of the present study was to systematically review the effects of Realsil (silybin-phospholipid-vitamin E complex) on liver enzymes in patients with NAFLD or NASH.

Methods

We searched Web of Science, MEDLINE, Google Scholar, Cochrane Library, Science Direct, ProQuest, Scopus, and 1868 articles were found up to December 2018. Four studies that examined the effect of Realsil intake on liver enzymes among NAFLD or NASH patients were included. Exclusion criteria include: animal studies, studies with the design other than clinical trials, studies on non-adult individuals, studies that assess the effect of vitamin E, silybin, or phospholipid solely, studies that examined the effect of Realsil on other outcomes, or studies with insufficient data.

Results

The analysis demonstrated that Realsil intake led to a significant decrease in Gamma-Glutamyl Transpeptidase (GGT) levels (standardized mean difference (SMD) =-0.37; 95% confidence interval (CI]): -0.68 to -0.06). Realsil intake non-significantly decrease alanine transaminase (ALT) levels (SMD=-1.02 U/L; 95% CI: -2.23 to 0.20) and non-significantly increase aspartate aminotransferase (AST) levels (SMD = 0.17 U/L; 95% CI: -0.26-0.61).

Conclusion

Realsil intake was associated with a significantly decreased circulating GGT level without any significant effect on AST and ALT levels.

Silybin ameliorates hepatic lipid accumulation and modulates global metabolism in an NAFLD mouse model

Silybin shows good effects against obesity and metabolic syndrome, but the systemic modulation effect of silybin has not been fully revealed. This study aims to investigate the metabolic regulation by silybin of nonalcoholic fatty liver disease (NAFLD). C57BL/6 J mice were fed a high-fat/high-cholesterol diet for 8 weeks and treated with silybin (50 or 100 mg/kg/day) and sodium tauroursodeoxycholate (TUDCA, 50 mg/kg/day) by gavage for the last 4 weeks. Blood biochemical indexes and hepatic lipid measurement as well as Oil red O staining of the liver were conducted to evaluate the model and the lipid-lowering effect of silybin and TUDCA. Furthermore, serum and liver samples were detected by a metabolomic platform based on gas chromatography-mass spectrometry (GC/MS). Multivariate/univariate data analysis and pathway analysis were used to investigate differential metabolites and metabolic pathways. The results showed that the mouse NAFLD model was established successfully and that silybin and TUDCA significantly lowered both serum and hepatic lipid accumulation. Metabolomic analysis of serum and liver showed that a high-fat/high-cholesterol diet caused abnormal metabolism of metabolites involved in lipid metabolism, polyol metabolism, amino acid metabolism, the urea cycle and the TCA cycle. Silybin and TUDCA treatment both reversed metabolic disorders caused by HFD feeding. In conclusion, a high-fat/high-cholesterol diet caused metabolic abnormalities in the serum and liver of mice, and silybin treatment improved hepatic lipid accumulation and modulated global metabolic pathways, which provided a possible explanation of its multiple target mechanism.

Aquaporin-9 is involved in the lipid-lowering activity of the nutraceutical silybin on hepatocytes through modulation of autophagy and lipid droplets composition

Hepatic steatosis is the hallmark of non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome and insulin resistance with potential evolution towards non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. Key roles of autophagy and oxidative stress in hepatic lipid accumulation and NAFLD progression are recognized. Here, we employed a rat hepatoma cell model of NAFLD progression made of FaO cells exposed to oleate/palmitate followed or not by TNFα treatment to investigate the molecular mechanisms through which silybin, a lipid-lowering nutraceutical, may improve hepatic lipid dyshomeostasis. The beneficial effect of silybin was found to involve amelioration of the fatty acids profile of lipid droplets, stimulation of the mitochondrial oxidation and upregulation of a microRNA of pivotal relevance in hepatic fat metabolism, miR-122. Silybin was also found to restore the levels of Aquaporin-9 (AQP9) and glycerol permeability while reducing the activation of the oxidative stress-dependent transcription factor NF-κB, and autophagy turnover. In conclusion, silybin was shown to have molecular effects on signaling pathways that were previously unknown and potentially protect the hepatocyte. These actions intersect TG metabolism, fat-induced autophagy and AQP9-mediated glycerol transport in hepatocytes.

Silybin Modulates Collagen Turnover in an In Vitro Model of NASH

Silybin has been proposed as a treatment for nonalcoholic steatohepatitis (NASH). In this study, we assessed the effect of Silybin in a well-established in vitro coculture model of early-stage NASH. LX2 and Huh7 cells were exposed to free fatty acid (FFA) and Silybin as mono- or coculture (SCC). Cell viability, LX2 activation, collagen deposition, metalloproteinase 2 and 9 (MMP2-9) activity, and ROS generation were determined at 24, 96, and 144 h. Exposure to FFA induced the activation of LX2 as shown by the increase in cell viability and upregulation of collagen biosynthesis. Interestingly, while cotreatment with Silybin did not affect collagen production in LX2, a significant reduction was observed in SCC. MMP2-9 activity was reduced in FFA-treated Huh7 and SCC and cotreatment with Silybin induced a dose-dependent increase, while no effect was observed in LX2. Silybin also showed antioxidant properties by reducing the FFA-induced production of ROS in all the cell systems. Based on these data, Silybin exerts its beneficial effects by reducing LX2 proliferation and ROS generation. Moreover, MMP2-9 modulation in hepatocytes represents the driving mechanism for the net reduction of collagen in this NASH in vitro model, highlighting the importance of hepatic cells interplay in NASH development and resolution.

Piperine enhances the bioavailability of silybin via inhibition of efflux transporters BCRP and MRP2

BACKGROUND

Although silybin serves as a well-known hepatoprotective agent with prominent anti-inflammatory, anti-oxidant and anti-fibrotic activities, its low bioavailability limits its application in the treatment of chronic liver diseases. However, novel formulation products with increased solubility were not sufficient to achieve pharmacologically meaningful concentrations of silybin in the clinical studies even used at high dosage.

HYPOTHESIS/PURPOSE

We hypothesized that inhibiting efflux transporter(s) and/or glucuronidation by piperine might enhance the bioavailability and efficacy of silybin.

METHODS

Pharmacokinetics of silybin given alone or in-combination with piperine was determined by a validated LC-MS method. A CCl₄ induced rat model of liver injury was prepared and verified for comparing the effects of silybin and combination treatment. To investigate the underlying mechanism, the inhibition effects of piperine on transportation of silybin were performed in Caco-2 and transfected MDCKII cell lines as well as sandwich-cultured rat hepatocytes (SCH). Human liver microsomes incubation was used for exploring the modulation effects of piperine on the phase-2 metabolism of silybin.

RESULTS

In the present study, we demonstrated for the first time that piperine as a bioenhancer increased the bioavailability of silybin (146%- 181%), contributing to a boosted therapeutic effect in CCl₄-induced acute liver-injury rat model. The underlying mechanisms involved that piperine enhanced the absorption of silybin by inhibiting the efflux transporters including MRP2 and BCRP but not MDR1 in Caco-2 and transfected MDCKII cell lines. Moreover, piperine could inhibit the biliary excretion of silybin and conjugated metabolites in sandwich-cultured rat hepatocytes. Notably, we found that piperine did not affect the phase-2 metabolism of silybin.

CONCLUSION

Efflux transporters play an important role in the pharmacokinetic behavior of flavolignans, and modulating these transporters by bioenhancer such as piperine could enhance the in vivo absorption of silybin, leading to more effective treatments.

Superior silybin bioavailability of silybin-phosphatidylcholine complex in oily-medium soft-gel capsules versus conventional silymarin tablets in healthy volunteers

BACKGROUND

Fibrosis is a response to chronic liver disease that results in excessive accumulation of extracellular matrix proteins and formation of scar tissue. Fibrosis represents a clinical challenge of worldwide significance. Several studies have demonstrated that many natural products and herbal medicines have activity against liver fibrosis, and extracts of milk thistle such as silymarin and silybin are the natural compounds most commonly prescribed for liver diseases. Therefore, we sought to assess and compare the pharmacokinetic properties and bioavailability of silybin-phosphatidylcholine complex in oily-medium soft-gel capsules and conventional silymarin tablets in healthy Mexican volunteers.

METHODS

We enrolled 23 healthy volunteers to participate in a prospective, balanced, blind, single-dose, two-way crossover study with a one-week washout period. Fasting participants received either 45 mg silybin-phosphatidylcholine complex or 70 mg silymarin to assess which formulation provided better bioavailability of silybin. Plasma was obtained and analysed for silybin concentration using a validated ultra-performance liquid chromatography-tandem mass spectroscopy method. Pharmacokinetic parameters were obtained by non-compartmental analysis and values were compared by analysis of variance for a crossover design. Ratios of maximum plasma drug concentration and area under the curve (AUC) were obtained and 90% confidence intervals were calculated.

RESULTS

The 23 healthy subjects (11 women, 12 men) who participated in the study were aged 22-31 years old (average: 28), average weight 64.8 kg, height 1.65 m and body mass index 23.5 kg/m². Plasma levels of silybin were higher after the administration of silybin-phosphatidylcholine complex capsules compared with that after conventional silymarin tablets (P <  0.0001).

CONCLUSIONS

The silybin-phosphatidylcholine complex in oily-medium soft-gel capsules seems to provide superior bioavailability. However, clinical studies must be performed to demonstrate its clinical relevance in the treatment of liver diseases.

TRIAL REGISTRATION

NCT03440164 ; registered on November 11, 2016.

Metabolic and vascular effects of silybin in hypertensive patients with high 1-h post-load plasma glucose

Hypertensive patients with normal glucose tolerance (NGT) but 1-h post-load plasma glucose ≥ 155 mg/dl (1-h high), during an oral glucose tolerance test (OGTT), show higher insulin resistance and multiple target organ damages. Experimental and clinical studies demonstrate that silybin presents anti-inflammatory and metabolic effects, improving insulin resistance and endothelial dysfunction. This study aims to evaluate the effects of the complex silybin-vitamin E and phospholipids on inflammatory, metabolic and vascular parameters in NGT 1-h high hypertensive patients. This is a pilot, single arm, interventional, longitudinal study enrolling 50 Caucasian NGT 1-h high hypertensive outpatients, 27 men and 23 women, age range 42-60 years (mean + SD = 52 ± 7). After 6 months of silybin intake, there is a significant improvement in metabolic profile. The glucose response during OGTT significantly improves (AUCglucose_0-120 309.6 ± 63.4 at baseline vs 254.6 ± 35.5 at the follow-up, ∆ = - 55, 95% CI from - 67 to - 43, p < 0.0001), so as insulin response (AUCinsulin_0-120 238.2 ± 99.1 vs 159.3 ± 44.9, ∆ = - 78.9, 95% CI from - 100.0 to - 57.8, p < 0.0001), in accordance with the increase of insulin sensitivity index Matsuda. Silybin intake is associated with a significant reduction of both clinical and central systolic blood pressure, with betterment in clinical and central pulse pressure and reduction of arterial stiffness parameters. In conclusion, this study demonstrates that silybin may improve the metabolic aspect and vascular damage in NGT 1-h high hypertensive patients who are at higher metabolic and cardiovascular risk. Thus, in these patients, silybin might strengthen the effect of antihypertensive drugs giving further cardiovascular protection.

Supersaturated polymeric micelles for oral silybin delivery: the role of the Soluplus-PVPVA complex

Increasing the degree of supersaturation of drugs and maintaining their proper stability are very important in improving the oral bioavailability of poorly soluble drugs by a supersaturated drug delivery system (SDDS). In this study, we reported a complex system of Soluplus–Copovidone (Soluplus–PVPVA) loaded with the model drug silybin (SLB) that could not only maintain the stability of a supersaturated solution but also effectively promote oral absorption. The antiprecipitation effect of the polymers on SLB was observed using the solvent-shift method. In addition, the effects of the polymers on absorption were detected by cellular uptake and transport experiments. The mechanisms by which the Soluplus–PVPVA complex promotes oral absorption were explored by dynamic light scattering, transmission electron microscopy, fluorescence spectra and isothermal titration calorimetry analyses. Furthermore, a pharmacokinetic study in rats was used to demonstrate the advantages of the Soluplus–PVPVA complex. The results showed that Soluplus and PVPVA spontaneously formed complexes in aqueous solution via the adsorption of PVPVA on the hydrophilic-hydrophobic interface of the Soluplus micelle, and the Soluplus–PVPVA complex significantly increased the absorption of SLB. In conclusion, the Soluplus–PVPVA complex is a potential SDDS for improving the bioavailability of hydrophobic drugs.

Silybin Alleviates Hepatic Steatosis and Fibrosis in NASH Mice by Inhibiting Oxidative Stress and Involvement with the Nf-κB Pathway

BACKGROUND AND AIM

Silybin is the major biologically active compound of silymarin, the standardized extract of the milk thistle (Silybum marianum). Increasing numbers of studies have shown that silybin can improve nonalcoholic steatohepatitis (NASH) in animal models and patients; however, the mechanisms underlying silybin's actions remain unclear.

METHODS

Male C57BL/6 mice were fed a methionine-choline deficient (MCD) diet for 8 weeks to induce the NASH model, and silybin was orally administered to the NASH mice. The effects of silybin on lipid accumulation, hepatic fibrosis, oxidative stress, inflammation-related gene expression and nuclear factor kappa B (NF-κB) activities were evaluated by biochemical analysis, immunohistochemistry, immunofluorescence, quantitative real-time PCR and western blot.

RESULTS

Silybin treatment significantly alleviated hepatic steatosis, fibrosis and inflammation in MCD-induced NASH mice. Moreover, silybin inhibited HSC activation and hepatic apoptosis and prevented the formation of MDBs in the NASH liver. Additionally, silybin partly reversed the abnormal expression of lipid metabolism-related genes in NASH. Further study showed that the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway played important roles in the silybin-derived antioxidant effect, as evidenced by the upregulation of Nrf2 target genes in the silybin treatment group. In addition, silybin significantly downregulated the expression of inflammation-related genes and suppressed the activity of NF-κB signaling.

CONCLUSIONS

Silybin was effective in preventing the MCD-induced increases in hepatic steatosis, fibrosis and inflammation. The effect was related to alteration of lipid metabolism-related gene expression, activation of the Nrf2 pathway and inhibition of the NF-κB signaling pathway in the NASH liver.

Interaction of isolated silymarin flavonolignans with iron and copper

Silymarin, the standardized extract from the milk thistle (Silybum marianum), is composed mostly of flavonolignans and is approved in the EU for the adjuvant therapy of alcoholic liver disease. It is also used for other purported effects in miscellaneous nutraceuticals. Due to polyhydroxylated structures and low systemic bioavailability, these flavonolignans are likely to interact with transition metals in the gastrointestinal tract. The aim of this study was to analyze the interactions of pure silymarin flavonolignans with copper and iron. Both competitive and non-competitive methods at various physiologically relevant pH levels ranging from 4.5 to 7.5 were tested. Only 2,3‑dehydrosilybin was found to be a potent or moderately active iron and copper chelator. Silybin A, silybin B and silychristin A were less potent or inactive chelators. Both 2,3‑dehydrosilybin enantiomers (A and B) were equally active iron and copper chelators, and the preferred stoichiometries were mainly 2:1 and 3:1 (2,3‑dehydrosilybin:metal). Additional experiments showed that silychristin was the most potent iron and copper reductant. Comparison with their structural precursors taxifolin and quercetin is included as well. Based on these results, silymarin administration most probably affects the kinetics of copper and iron in the gastrointestinal tract, however, due to the different interactions of individual components of silymarin with these transition metals, the biological effects need to be evaluated in the future in a much more complex study.

In vitro inhibitory effects of major bioactive constituents of Andrographis paniculata, Curcuma longa and Silybum marianum on human liver microsomal morphine glucuronidation: A prediction of potential herb-drug interactions arising from andrographolide, curcumin and silybin inhibition in humans

This study aimed to investigate the liver microsomal inhibitory effects of silybin, silychristin, andrographolide, and curcumin by using morphine as an in vitro UGT2B7 probe substrate, and predict the magnitude of the herb-drug interaction arising from these herbal constituents' inhibition in vivo. Studies were performed in the incubation with and without bovine serum albumin (BSA). Andrographolide and curcumin showed a marked inhibition on morphine 3- and 6-glucuronidation with IC50 of 50&87 and 96&111 μM, respectively. In the presence of 2%BSA, andrographolide also showed a strong inhibition on morphine 3- and 6-glucuronidation (IC50 4.4&21.6 μM) whereas curcumin showed moderate inhibition (IC50 338&333 μM). In the absence and presence of 2%BSA, morphine 3- and 6-glucuronidation was moderately inhibited by silybin (IC50 583&862 and 1252&1421 μM, respectively), however was weakly inhibited by silychristin (IC50 3527&3504 and 1124&1530 μM, respectively). The Ki of andrographolide, curcumin and silybin on morphine 3- and 6-glucuronidation were 7.1&9.5, 72.7&65.2, and 224.5&159.7 μM, respectively, while the respective values generated from the system containing 2%BSA were 2.4&3.1, 96.4&108.8, and 366.3&394.5 μM. Using the in vitro and in vivo extrapolation approach, andrographolide was herbal component that may have had a potential interaction in vivo when it was co-administered with morphine.

Silibinin phosphodiester glyco-conjugates: Synthesis, redox behaviour and biological investigations

New silibinin phosphodiester glyco-conjugates were synthesized by efficient phosphoramidite chemistry and were fully characterized by 2D-NMR. A wide-ranging study focused on the determination of their pKa and E° values as well as on their radical scavenging activities by different assays (DPPH, ABTS⁺ and HRSA) was conducted. The new glyco-conjugates are more water-soluble than silibinin, and their radical scavenging activities are higher than those of silibinin. The conjugation therefore improves both the water solubilities and antioxidant activities of the flavonolignan moieties. The serum stability was evaluated under physiological conditions, and the glyco-conjugates degraded with half-lives of 40-70 h, making them useful in pro-drug approaches. We started by treating androgen-dependent prostate cancer (PCa) LNCaP cells and then expanded our studies to androgen-independent PCa PC3 and DU145 cells. In most cases, the new derivatives significantly reduced both total and live cell numbers, albeit at different levels. Anti-HIV activities were evaluated and the glucosamine-phosphate silibinin derivative showed higher activity (IC₅₀ = 73 μM) than silibinin.

Metabolism of flavonolignans in human hepatocytes

This study examined the in vitro biotransformation of eight structurally related flavonolignans, namely silybin, 2,3-dehydrosilybin, silychristin, 2,3-dehydrosilychristin, silydianin, 2,3-dehydrosilydianin, isosilybin A and isosilybin B. The metabolic transformations were performed using primary cultures of human hepatocytes and recombinant human cytochromes P450 (CYPs 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1 and 3A4). The metabolites produced were analyzed by ultra-performance liquid chromatography coupled with tandem mass spectrometry. We found that each of the tested compounds was metabolized in vitro by one or more CYP enzymes, which catalyzed O-demethylation, hydroxylation, hydrogenation and dehydrogenation reactions. In human hepatocytes, silybin, 2,3-dehydrosilybin, silychristin, 2,3-dehydrosilychristin, and isosilybins A and B were directly conjugated by sulfation or glucuronidation. Moreover, isosilybin A was also converted to a methyl derivative, while isosilybin B was hydroxylated and methylated. Silydianin and 2,3-dehydrosilydianin were found to undergo hydrogenation and/or glucuronidation. In addition, 2,3-dehydrosilydianin was found to be metabolically the least stable flavonolignan in human hepatocytes, and its main metabolite was a cleavage product corresponding to a loss of CO. We conclude that the hepatic biotransformation of flavonolignans primarily involves the phase II conjugation reactions, however in some cases the phase I reactions may also occur. These results are highly relevant for research focused on flavonolignan metabolism and pharmacology.

Regioselective synthesis of 7-O-esters of the flavonolignan silibinin and SARs lead to compounds with overadditive neuroprotective effects

A series of neuroprotective hybrid compounds was synthesized by conjugation of the flavonolignan silibinin with natural phenolic acids, such as ferulic, cinnamic and syringic acid. Selective 7-O-esterfication without protection groups was achieved by applying the respective acyl chlorides. Sixteen compounds were obtained and SARs were established by evaluating antioxidative properties in the physicochemical FRAP assay, as well as in a cell-based neuroprotection assay using murine hippocampal HT-22 cells. Despite weak activities in the FRAP assay, esters of the α,β-unsaturated acids showed pronounced overadditive effects at low concentrations greatly exceeding the effects of equimolar mixtures of silibinin and the respective acids in the neuroprotection assay. Cinnamic and ferulic acid esters (5a and 6a) also showed overadditive effects regarding inhibition of microglial activation, PC12 cell differentiation, in vitro ischemia as well as anti-aggregating abilities against Aβ42 peptide and τ protein. Remarkably, the esters of ferulic acid with silybin A and silybin B (11a and 11b) showed a moderate but significant difference in both neuroprotection and in their anti-aggregating capacities. The results demonstrate that non-toxic natural antioxidants can be regioselectively connected as esters with medium-term stability exhibiting very pronounced overadditive effects in a portfolio of biological assays.

A Randomized Trial of Silymarin for the Treatment of Nonalcoholic Steatohepatitis

BACKGROUND & AIMS

Silymarin is a complex mixture of 6 major flavonolignans and other minor polyphenolic compounds derived from the milk thistle plant Silybum marianum; it has shown antioxidant, anti-inflammatory and antifibrotic effects, and may be useful in patients with nonalcoholic fatty liver disease (NAFLD). We aimed to study the efficacy of silymarin in patients with nonalcoholic steatohepatitis (NASH)-the more severe form of NAFLD.

METHODS

We performed a randomized, double-blind, placebo-controlled trial of consecutive adults with biopsy-proven NASH and a NAFLD activity score (NAS) of 4 or more at a tertiary care hospital in Kuala Lumpur, Malaysia, from November 2012 through August 2014. Patients were randomly assigned to groups given silymarin (700 mg; n = 49 patients) or placebo (n = 50 patients) 3 times daily for 48 weeks. After this 48-week period, liver biopsies were repeated. The primary efficacy outcome was a decrease of 30% or more in NAS; findings from 48-week liver biopsies were compared with those from the baseline biopsy. Secondary outcomes included changes in steatosis, lobular inflammation, hepatocyte ballooning, NAS and fibrosis score, and anthropometric measurements, as well as glycemic, lipid, and liver profiles and liver stiffness measurements.

RESULTS

The percentage of patients achieving the primary efficacy outcome did not differ significantly between the groups (32.7% in the silymarin group vs 26.0% in the placebo group; P = .467). A significantly higher proportion of patients in the silymarin group had reductions in fibrosis based on histology (reductions of 1 point or more; 22.4%) than did the placebo group (6.0%; P = .023), and based on liver stiffness measurements (decrease of 30% or more; 24.2%) than did the placebo group (2.3%; P = .002). The silymarin group also had significant reductions in mean aspartate aminotransferase to platelet ratio index (reduction of 0.14, P = .011 compared with baseline), fibrosis-4 score (reduction of 0.20, P = .041 compared with baseline), and NAFLD fibrosis score (reduction of 0.30, P < .001 compared with baseline); these changes were not observed in the placebo group (reduction of 0.07, P = .154; increase of 0.18, P = .389; and reduction of 0.05, P = .845, respectively). There was no significant difference between groups in number of adverse events; adverse events that occurred were not attributed to silymarin.

CONCLUSIONS

In a randomized trial of 99 patients, we found that silymarin (700 mg, given 3 times daily for 48 weeks) did not reduce NAS scores by 30% or more in a significantly larger proportion of patients with NASH than placebo. Silymarin may reduce liver fibrosis but this remains to be confirmed in a larger trial. It appears to be safe and well tolerated. ClinicalTrials.gov: NCT02006498.

The study of flavonolignan association patterns in fruits of diverging Silybum marianum (L.) Gaertn. chemotypes provides new insights into the silymarin biosynthetic pathway

Silymarin is the phytochemical with medicinal properties extracted from Silybum marianum (L.) Gaertn. fruits. Yet, little information is available about silymarin biosynthesis. Moreover, the generally accepted pathway, formulated thus far, is not in agreement with actual experimental measurements on flavonolignan contents. The present work analyses flavonolignan and taxifolin content in 201 S. marianum samples taking into consideration a wide phenotypic variability. Two stable chemotypes were identified: one characterized by both high silychristin and silybin content (chemotype A) and another by a high silydianin content (chemotype B). Through the correlation analysis of samples divided according to chemotype, it was possible to construct a simplified silymarin biosynthetic pathway that is sufficiently versatile in explaining experimental results responding to the actually unresolved questions about this process. The proposed pathway highlights that three separate and equally sized metabolite pools exist, namely: diastereoisomers A (silybin A plus isosilybin A), diastereoisomers B (silybin B plus isosilybin B) and silychristin. In both A and B diastereoisomers pools, isosilybin A and isosilybin B always represent a given amount of the metabolite flux through the specific metabolite pool suggesting the possible involvement of dirigent protein-like enzymes. We suggest that chemotype B possesses a complete silymarin biosynthetic pathway in which silydianin biosynthesis is enzymatically controlled. On the contrary, chemotype A is probably a natural mutant unable to biosynthesize silydianin. The present simplified pathway for silymarin biosynthesis will constitute an important tool for the further understanding of the reactions that drive flavonolignan biosynthesis in S. marianum.

The efficiency and mechanism of N-octyl-O, N-carboxymethyl chitosan-based micelles to enhance the oral absorption of silybin

This study demonstrates the preparation of a silybin-loaded N-octyl-O, N-carboxymethyl chitosan micelle (OCC-SLB) to enhance the oral absorption efficiency of silybin (SLB) and investigate the related mechanisms of enhancement. Firstly, the physicochemical properties of OCC and OCC-SLB micelles, including critical micelle concentration (CMC), particle size, zeta potential, drug-loading, etc., were determined. Results of pharmacokinetic studies on rats then confirmed a desirable enhancement in the oral bioavailability of SLB by OCC-SLB micelles compared with a stock SLB suspension solution. Subsequently, uptake studies on the Caco-2 cell line demonstrated that OCC-SLB micelles effectively accumulated SLB or rhodamine-123 into cells through clathrin and caveolae-mediated endocytosis and the inhibition of P-glycoprotein (P-gp) efflux. In addition, results of the Caco-2 transport study further clarified that OCC-SLB micelles enhanced the permeability of SLB via tight junction opening and clathrin-mediated transcytosis across the endothelium. These findings indicated the OCC micelle platform as a potential delivery vehicle for oral administration of P-gp substrates such as SLB.

The protective effects of silybin on the cytotoxicity of thiram in human, rat and chicken cell cultures

The study objective was a determination of thiram cytotoxicity and silybin cytoprotective activity in course of the fungicide impact on cell metabolism and membrane integrity. Firstly, human, rat, chicken hepatoma cells and rat myoblasts cultures were incubated with thiram. The results showed higher sensitivity of myoblasts on thiram exposure than the hepatoma cells. Among hepatoma cells, the chicken cultures were the most sensitive on the fungicide endangering. The mitochondrial activity was the most thiram affected function within all types the cell lines used. When silybin co-acted with thiram, an increase of the cell viability was recorded. The EC₅₀-values were higher for thiram subjected to interaction with silybin than the effect of alone thiram action. The interaction mode between the studied compounds shown by combination index (CI) represented an antagonistic or an additive nature and was depended on thiram concentration, type of the cells and the assay used. Moreover, the morphology changes were dependent on silybin presence in the cell cultures subjected to thiram impact at the same time. Staining with Hoechst 33342 and propidium ioidium revealed the apoptosis cell death in the incubation cultures. Definitely, the results have shown a potential of silybin to protect the cultured cells in course of cytotoxicity induced by thiram. However, future studies taking into account other endpoints of thiram cytotoxicity pathways including species differences and the cytoprotection efficacy could be of interest.