Comparative pharmacokinetics of silipide and silymarin in rats

7-O-tyrosyl Silybin Derivatives as a Novel Set of Anti-Prostate Cancer Compounds

Silybin is a natural compound extensively studied for its hepatoprotective, neuroprotective and anticancer properties. Envisioning the enhancement of silybin potential by suitable modifications in its chemical structure, here, a series of new 7-O-alkyl silybins derivatives were synthesized by the Mitsunobu reaction starting from the silybins and tyrosol-based phenols, such as tyrosol (TYR, 3), 3-methoxytyrosol (MTYR, 4), and 3-hydroxytyrosol (HTYR, 5). This research sought to explore the antioxidant and anticancer properties of eighteen new derivatives and their mechanisms. In particular, the antioxidant properties of new derivatives outlined by the DPPH assay showed a very pronounced activity depending on the tyrosyl moiety (HTYR > MTYR >> TYR). A significant contribution of the HTYR moiety was observed for silybins and 2,3-dehydro-silybin-based derivatives. According to the very potent antioxidant activity, 2,3-dehydro-silybin derivatives 15ab, 15a, and 15b exerted the most potent anticancer activity in human prostate cancer PC-3 cells. Furthermore, flow cytometric analysis for cell cycle and apoptosis revealed that 15ab, 15a, and 15b induce strong G1 phase arrest and increase late apoptotic population in PC-3 cells. Additionally, Western blotting for apoptotic marker cleaved caspase-3 confirmed apoptosis induction by these silybin derivatives in PC-3 cells. These findings hold significant importance in the investigation of anticancer properties of silybin derivatives and strongly encourage swift investigation in pre-clinical models and clinical trials.

Pharmaceutical prospects of Silymarin for the treatment of neurological patients: an updated insight

Background

Silymarin is a polyphenolic flavonoid complex extricated from dried fruits and seeds of the plant Silybum marianum L. Chemically, it is a mixture of flavonolignan complexes consisting of silybin, isosilybin, silychristin, silydianin, a minor quantity of taxifolin, and other polyphenolic compounds, which possess different bio medicinal values.

Purpose

This review critically looks into the current status, pharmaceutical prospects and limitations of the clinical application of Silymarin for treating neurological disorders. In particular, Silymarin's medicinal properties and molecular mechanisms are focused on providing a better-compiled understanding helpful in its neuro-pharmacological or therapeutic aspects.

Methods

This review was compiled by the literature search done using three databases, i.e., PubMed (Medline), EMBASE and Science Direct, up to January 2023, using the keywords-Silymarin, neurological disorders, cognitive disorders, Type 2 Diabetes, pharmaceutical prospects and treatment. Then, potentially relevant publications and studies (matching the eligible criteria) were retrieved and selected to explain in this review using PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) study flow chart.

Result

Since its discovery, it has been widely studied as a hepatoprotective drug for various liver disorders. However, in the last 10-15 years, several research studies have shown its putative neuroprotective nature against various brain disorders, including psychiatric, neurodegenerative, cognitive, metabolic and other neurological disorders. The main underlying neuroprotective mechanisms in preventing and curing such disorders are the antioxidant, anti-inflammatory, anti-apoptotic, pro-neurotrophic and pro-estrogenic nature of the bioactive molecules.

Conclusion

This review provides a lucid summary of the well-studied neuroprotective effects of Silymarin, its underlying molecular mechanisms and current limitations for its usage during neurological disorders. Finally, we have suggested a future course of action for developing it as a novel herbal drug for the treatment of brain diseases.

Combinations of grape seed procyanidin extract and milk thistle silymarin extract against lung cancer - The role of MiR-663a and FHIT

AIMS

Grape seed procyanidin extract (GSE), and milk thistle silymarin extract (MTE) contain structurally distinct polyphenols, and each agent has been shown to exert antineoplastic effects against lung cancer. We hypothesize that combinations of GSE and MTE will additively enhance their anticancer effects against lung cancer.

MATERIALS AND METHODS

The anti-proliferative effects of GSE, MTE and combinations were evaluated in lung neoplastic cell lines. A dose range finding (DRF) study to determine safety, bioavailability and bioactivity, followed by human lung cancer xenograft efficacy studies were conducted in female nude mice with once daily gavage of leucoselect phytosome (LP), a standardized GSE, and/or siliphos, a standardized MTE. The roles of tumor suppressors miR-663a and its predicted target FHIT in mediating the additive, anti-proliferative effecs of GSE/MTE were also assessed.

KEY FINDINGS

GSE with MTE additively inhibited lung preneoplastic and cancer cell proliferations. Mice tolerated all dosing regimens in the DRF study without signs of clinical toxicity nor histologic abnormalities in the lungs, livers and kidneys. Eight weeks of LP and siliphos additively inhibited lung tumor xenograft growth. Plasma GSE/metabolites and MTE/metabolites showed that the combinations did not decrease systemic bioavailabilities of each agent. GSE and MTE additively upregulated miR-663a and FHIT in lung cancer cell lines; transfection of antisense-miR-663a significantly abrogated the anti-proliferative effects of GSE/MTE, upregulation of FHIT mRNA and protein. LP and siliphos also additively increased miR-663a and FHIT protein in lung tumor xenografts.

SIGNIFICANCE

Our findings support clinical translations of combinations of GSE and MTE against lung cancer.

Enhanced bioavailability and hepatoprotective effect of silymarin by preparing silymarin-loaded solid dispersion formulation using freeze-drying method

This study aimed to develop a solid dispersion formulation of silymarin (Silymarin-SD) using freeze-drying method to enhance its oral bioavailability (BA) by inhibiting the intestinal first-pass effect and increasing its solubility and permeability. Silymarin-SD formulation (i.e., silymarin:tween 80:hydroxypropyl cellulose (HPC) = 1:1:3 (w/w/w) significantly increased silymarin permeability in the duodenum, jejunum, and ileum by decreasing the efflux ratio of silymarin and by inhibiting silymarin-glucuronidation activity, in which tween 80 played a crucial role. As a result, orally administered Silymarin-SD formulation increased plasma silymarin concentrations and decreased silymarin-glucuronide in rats compared with silymarin alone and silymmarin:D-α-tocopherol polyethylene glycol 1000 succinate (1:1, w/w) formulation. In addition to modulating intestinal first-pass effect, Silymarin-SD formulation showed a significantly higher cumulative dissolution for 120 min compared with that of silymarin from the physical mixture (PM) of the same composition as Silymarin-SD and silymarin alone; the relative BA of silymarin-SD increased to 215% and 589% compared with silymarin-PM and silymarin alone, respectively. This could be attributed to the amorphous status of the Silymarin-SD formulation without chemical interaction with excipients, such as tween 80 and HPC. Moreover, the hepatoprotective effect of Silymarin-SD in acetaminophen-induced acute hepatotoxicity, as estimated from the alanine aminotransferase and aspartate aminotransferase values, was superior to that of silymarin. In conclusion, the increase in the dissolution rate and intestinal permeability of silymarin, and the inhibition of silymarin-glucuronidation by the Silymarin-SD formulation, prepared using tween 80 and HPC, increased its plasma concentration and resulted in a superior hepatoprotective effect compared to silymarin.

Silibinin Ameliorates Formaldehyde-Induced Cognitive Impairment by Inhibiting Oxidative Stress

Silibinin is a flavonoid extracted from the medicinal plant Silybum marianum (milk thistle), traditionally used to treat liver disease. Recent studies have shown that the antioxidative stress and anti-inflammatory effects of milk thistle are used in the treatment of neurological diseases. Silibinin has antioxidative stress and antiapoptotic effects and reduces cognitive impairment in models of Alzheimer's disease (AD). However, the underlying mechanism of silibinin related to improvement of cognition remains poorly understood. In this study, we used the model of lateral ventricle injection of formaldehyde to examine the related mechanism of silibinin in improving cognitive impairment disorders. Oral administration of silibinin for three weeks significantly attenuated the cognitive deficits of formaldehyde-induced mice in a Y-maze test and Morris water maze test. Y-maze results show that silibinin increases the rate of spontaneous response alternation in FA-induced mice. Silibinin increases the target quadrant spending time and decreases escape latency in the Morris water maze test. We examined the effect of silibinin on the NRF2 signaling pathway, and silibinin promoted the nuclear transfer of NRF2 and increased the expression of HO-1 but did not significantly increase the protein expression of NRF2 in the hippocampus. Well, silibinin reduces the content of DHE and decreases the levels of apoptosis of mature neuron cells. We investigated the effect of silibinin on the content of formaldehyde degrading enzymes; biochemical analyses revealed that silibinin increased GSH and ALDH2 in formaldehyde-induced mice. In addition, as one of the pathological changes of AD, TAU protein is also hyperphosphorylated in FA model mice. Silibinin inhibits the expression of GSK-3β in model mice, thereby reducing the phosphorylation of TAU proteins ser396 and ser404 mediated by GSK3β. Based on our findings, we verified that the mechanism of silibinin improving cognitive impairment may be antioxidative stress, and silibinin is one of the potentially promising drugs to prevent formaldehyde-induced cognitive impairment.

Role of silymarin (Silybum marianum) in the prevention of colistin-induced acute nephrotoxicity in rats

Silymarin (Silybum marianum) has some protective effects against drug toxicity (cisplatin, acetaminophen, adriamycin, gentamicin etc.). Colistin is a strong antimicrobial, which is frequently used in the treatment of resistant gram-negative bacterial infections in recent years although it has nephrotoxic potential. This study was aimed to determine the role of silymarin against colistin-induced acute nephrotoxicity (CIN). Rats were randomly divided into four groups. The control group was treated with tap water whereas groups 2 and 3 received silymarin (orally, 100 mg/kg/day) and colistin (intraperitoneally, 750.000 IU/kg/day) for seven days, respectively. Group 4 received both 750,000 IU/kg/day colistin and 100 mg/kg/day silymarin for seven days. After euthanasia, histopathological and biochemical examinations were completed for the kidney tissue specimens and blood samples. All parameters of the control and silymarin groups were similar. Severe weight loss was seen in the groups receiving colistin (groups 3 and 4). Silymarin significantly increased glutathione peroxidase and superoxide dismutase levels when administered with colistin in group 4 only. Acute tubular injury, tubular necrosis, meduller congestion, interstitial inflammation and apoptotic indices of colistin group were significantly higher than the control group. The administration of colistin with silymarin (group 4) was able to make some improvements in tubular necrosis and significant increase in antioxidant capacity. Silymarin increased antioxidant enzyme activity only when used in combination with colistin. The effects of silymarin may become more pronounced when used at higher doses or with a longer duration of treatment and may prevent nephrotoxicity.

Role of Silymarin in Cancer Treatment: Facts, Hypotheses, and Questions

The flavonoid silymarin extracted from the seeds of Sylibum marianum is a mixture of 6 flavolignan isomers. The 3 more important isomers are silybin (or silibinin), silydianin, and silychristin. Silybin is functionally the most active of these compounds. This group of flavonoids has been extensively studied and they have been used as hepato-protective substances for the mushroom Amanita phalloides intoxication and mainly chronic liver diseases such as alcoholic cirrhosis and nonalcoholic fatty liver. Hepatitis C progression is not, or slightly, modified by silymarin. Recently, it has also been proposed for SARS COVID-19 infection therapy. The biochemical and molecular mechanisms of action of these substances in cancer are subjects of ongoing research. Paradoxically, many of its identified actions such as antioxidant, promoter of ribosomal synthesis, and mitochondrial membrane stabilization, may seem protumoral at first sight, however, silymarin compounds have clear anticancer effects. Some of them are: decreasing migration through multiple targeting, decreasing hypoxia inducible factor-1α expression, inducing apoptosis in some malignant cells, and inhibiting promitotic signaling among others. Interestingly, the antitumoral activity of silymarin compounds is limited to malignant cells while the nonmalignant cells seem not to be affected. Furthermore, there is a long history of silymarin use in human diseases without toxicity after prolonged administration. The ample distribution and easy accessibility to milk thistle-the source of silymarin compounds, its over the counter availability, the fact that it is a weed, some controversial issues regarding bioavailability, and being a nutraceutical rather than a drug, has somehow led medical professionals to view its anticancer effects with skepticism. This is a fundamental reason why it never achieved bedside status in cancer treatment. However, in spite of all the antitumoral effects, silymarin actually has dual effects and in some cases such as pancreatic cancer it can promote stemness. This review deals with recent investigations to elucidate the molecular actions of this flavonoid in cancer, and to consider the possibility of repurposing it. Particular attention is dedicated to silymarin's dual role in cancer and to some controversies of its real effectiveness.

Systematic review of pharmacokinetics and potential pharmacokinetic interactions of flavonolignans from silymarin

Silymarin is an extract from the seeds (fruits) of Silybum marianum that contains flavonolignans and flavonoids. Although it is frequently used as a hepatoprotective agent, its application remains somewhat debatable, in particular, due to the low oral bioavailability of flavonolignans. Moreover, there are claims of its potential interactions with concomitantly used drugs. This review aims at a systematic summary and critical assessment of known information on the pharmacokinetics of particular silymarin flavonolignans. There are two known major reasons for poor systemic oral bioavailability of flavonolignans: (1) rapid conjugation in intestinal cells or the liver and (2) efflux of parent flavonolignans or formed conjugates back to the lumen of the gastrointestinal tract by intestinal cells and rapid excretion by the liver into the bile. The metabolism of phase I appears to play a minor role, in contrast to extensive conjugation and indeed the unconjugated flavonolignans reach low plasma levels after common doses. Only about 1%-5% of the administered dose is eliminated by the kidneys. Many in vitro studies tested the inhibitory potential of silymarin and its components toward different enzymes and transporters involved in the absorption, metabolism, and excretion of xenobiotics. In most cases, effective concentrations are too high to be relevant under real biological conditions. Most human studies showed no silymarin-drug interactions explainable by these suggested interferences. More interactions were found in animal studies, likely due to the much higher doses administered.

Enhanced Bioavailability and Efficacy of Silymarin Solid Dispersion in Rats with Acetaminophen-Induced Hepatotoxicity

We evaluated the bioavailability, liver distribution, and efficacy of silymarin-D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) solid dispersion (silymarin-SD) in rats with acetaminophen-induced hepatotoxicity (APAP) compared with silymarin alone. The solubility of silybin, the major and active component of silymarin, in the silymarin-SD group increased 23-fold compared with the silymarin group. The absorptive permeability of silybin increased by 4.6-fold and its efflux ratio decreased from 5.5 to 0.6 in the presence of TPGS. The results suggested that TPGS functioned as a solubilizing agent and permeation enhancer by inhibiting efflux pump. Thus, silybin concentrations in plasma and liver were increased in the silymarin-SD group and liver distribution increased 3.4-fold after repeated oral administration of silymarin-SD (20 mg/kg as silybin) for five consecutive days compared with that of silymarin alone (20 mg/kg as silybin). Based on higher liver silybin concentrations in the silymarin-SD group, the therapeutic effects of silymarin-SD in hepatotoxic rats were evaluated and compared with silymarin administration only. Elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels were significantly decreased by silymarin-SD, silymarin, and TPGS treatments, but these decreases were much higher in silymarin-SD animals than in those treated with silymarin or TPGS. In conclusion, silymarin-SD (20 mg/kg as silybin, three times per day for 5 days) exhibited hepatoprotective properties toward hepatotoxic rats and these properties were superior to silymarin alone, which may be attributed to increased solubility, enhanced intestinal permeability, and increased liver distribution of the silymarin-SD formulation.

Therapeutic Applications of Curcumin and its Novel Formulations in the Treatment of Bladder Cancer: A Review of Current Evidence

Bladder cancer, a life-threatening serious disease, is responsible for thousands of cancer-associated deaths worldwide. Similar to other malignancies, standard treatments of bladder cancer, such as Chemoradiotherapy, are not efficient enough in the affected patients. It means that, according to recent reports in the case of life quality as well as the survival time of bladder cancer patients, there is a critical requirement for exploring effective treatments. Recently, numerous investigations have been carried out to search for appropriate complementary treatments or adjuvants for bladder cancer therapy. Curcumin, a phenolic component with a wide spectrum of biological activities, has recently been introduced as a potential anti-cancer agent. It has been shown that this agent exerts its therapeutic effects via targeting a wide range of cellular and molecular pathways involved in bladder cancer. Herein, the current data on curcumin therapy for bladder cancer are summarized.

Silibinin-hydroxypropyl-β-cyclodextrin (SLB-HP-β-CD) complex prevents apoptosis in liver and kidney after hepatic ischemia-reperfusion injury

BACKGROUND

We investigated the protective effect of silibinin on rat liver and kidney after hepatic inschemia/reperfusion (I/R) injury.

METHODS AND MATERIALS

Sixty three male Wistar-type rats (median age 13 weeks; average weight 314 g) were subjected to I/R injury of the liver. They were randomly divided into three groups: Sham (n = 7), Control (C, n = 28) and Silibinin (Si, n = 28). The last group received intravenously silibinin. The C and Si groups were each subdivided in four subgroups according to euthanasia times (i.e., 60, 120, 180, 240 min). We assessed expression of caspase-3 and TUNEL assay, and biochemical and histological parameters.

RESULTS

At 240 min, expression of caspase-3 and TUNEL assay were statistically significantly lower in the Si compared to the C group for both liver and kidney. SGOT and SGPT were also statistically significantly lower in the Si than in the C group at all time points. Histological parameters of the liver were also improved in the Si group.

CONCLUSION

Silibinin was found to exhibit a protective effect on liver and kidney after hepatic I/R injury. The present results are encouraging for further studies and future clinical application.

Trehalose Conjugates of Silybin as Prodrugs for Targeting Toxic Aβ Aggregates

Alzheimer's disease (AD) is linked to the abnormal accumulation of amyloid β peptide (Aβ) aggregates in the brain. Silybin B, a natural compound extracted from milk thistle (Silybum marianum), has been shown to significantly inhibit Aβ aggregation in vitro and to exert neuroprotective properties in vivo. However, further explorations of silybin B's clinical potential are currently limited by three main factors: (a) poor solubility, (b) instability in blood serum, and (c) only partial knowledge of silybin's mechanism of action. Here, we address these three limitations. We demonstrate that conjugation of a trehalose moiety to silybin significantly increases both water solubility and stability in blood serum without significantly compromising its antiaggregation properties. Furthermore, using a combination of biophysical techniques with different spatial resolution, that is, TEM, ThT fluorescence, CD, and NMR spectroscopy, we profile the interactions of the trehalose conjugate with both Aβ monomers and oligomers and evidence that silybin may shield the "toxic" surfaces formed by the N-terminal and central hydrophobic regions of Aβ. Finally, comparative analysis with silybin A, a less active diastereoisomer of silybin B, revealed how even subtle differences in chemical structure may entail different effects on amyloid inhibition. The resulting insight on the mechanism of action of silybins as aggregation inhibitors is anticipated to facilitate the future investigation of silybin's therapeutic potential.

Silymarin as Supportive Treatment in Liver Diseases: A Narrative Review

Silymarin, an extract from milk thistle seeds, has been used for centuries to treat hepatic conditions. Preclinical data indicate that silymarin can reduce oxidative stress and consequent cytotoxicity, thereby protecting intact liver cells or cells not yet irreversibly damaged. Eurosil 85® is a proprietary formulation developed to maximize the oral bioavailability of silymarin. Most of the clinical research on silymarin has used this formulation. Silymarin acts as a free radical scavenger and modulates enzymes associated with the development of cellular damage, fibrosis and cirrhosis. These hepatoprotective effects were observed in clinical studies in patients with alcoholic or non-alcoholic fatty liver disease, including patients with cirrhosis. In a pooled analysis of trials in patients with cirrhosis, silymarin treatment was associated with a significant reduction in liver-related deaths. Moreover, in patients with diabetes and alcoholic cirrhosis, silymarin was also able to improve glycemic parameters. Patients with drug-induced liver injuries were also successfully treated with silymarin. Silymarin is generally very well tolerated, with a low incidence of adverse events and no treatment-related serious adverse events or deaths reported in clinical trials. For maximum benefit, treatment with silymarin should be initiated as early as possible in patients with fatty liver disease and other distinct liver disease manifestations such as acute liver failure, when the regenerative potential of the liver is still high and when removal of oxidative stress, the cause of cytotoxicity, can achieve the best results.

Silymarin Attenuates the Severity of Cerulein-Induced Acute Pancreatitis

OBJECTIVES

In this study, we investigated the anti-inflammatory effects of silymarin on cerulein-induced acute pancreatitis (AP) in mice.

METHODS

Cerulein (50 μg/kg) was injected intraperitoneally once hourly for 6 hours to induce AP. To investigate the prophylactic effects of silymarin, dimethyl sulfoxide or silymarin (25, 50, and 100 mg/kg) was injected intraperitoneally 1 hour before cerulein injection. To investigate the therapeutic effects of silymarin, dimethyl sulfoxide or silymarin (100 mg/kg) was injected intraperitoneally 1, 3, or 5 hours after the first cerulein injection. Blood, pancreas, and lungs were harvested 6 hours after the last cerulein injection.

RESULTS

Pre- and posttreatment with silymarin decreased the pancreas weight/body weight ratio and serum amylase activity. Furthermore, silymarin treatment inhibited pancreas and lung injury and neutrophil infiltration during cerulein-induced AP. In addition, silymarin inhibited increased secretion of proinflammatory cytokines such as interleukin 1β, interleukin 6, and tumor necrosis factor α. Finally, mitogen-activated protein kinases (MAPKs) and nuclear factor-κB were activated by cerulein, and only p38 in MAPK was inhibited by silymarin.

CONCLUSIONS

These findings suggest that silymarin attenuates the severity of AP through inhibition of p38 MAPKs and that silymarin could be a potential prophylactic and therapeutic agent for the treatment of AP.

Formulation of Nanomicelles to Improve the Solubility and the Oral Absorption of Silymarin

Two novel nanomicellar formulations were developed to improve the poor aqueous solubility and the oral absorption of silymarin. Polymeric nanomicelles made of Soluplus and mixed nanomicelles combining Soluplus with d-α-tocopherol polyethylene glycol 1000 succinate (vitamin E TPGS) were prepared using the thin film method. Physicochemical parameters were investigated, in particular the average diameter, the homogeneity (expressed as polydispersity index), the zeta potential, the morphology, the encapsulation efficiency, the drug loading, the critical micellar concentration and the cloud point. The sizes of ~60 nm, the narrow size distribution (polydispersity index ≤0.1) and the encapsulation efficiency >92% indicated the high affinity between silymarin and the core of the nanomicelles. Solubility studies demonstrated that the solubility of silymarin increased by ~6-fold when loaded into nanomicelles. Furthermore, the physical and chemical parameters of SLM-loaded formulations stored at room temperature and in refrigerated conditions (4 °C) were monitored over three months. In vitro stability and release studies in media miming the physiological conditions were also performed. In addition, both formulations did not alter the antioxidant properties of silymarin as evidenced by the 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH) assay. The potential of the nanomicelles to increase the intestinal absorption of silymarin was firstly investigated by the parallel artificial membrane permeability assay. Subsequently, transport studies employing Caco-2 cell line demonstrated that mixed nanomicelles statistically enhanced the permeability of silymarin compared to polymeric nanomicelles and unformulated extract. Finally, the uptake studies indicated that both nanomicellar formulations entered into Caco-2 cells via energy-dependent mechanisms.

Evaluation of the Cytotoxicity and Genotoxicity of Flavonolignans in Different Cellular Models

Flavonolignans are the main components of silymarin, which represents 1.5-3% of the dry fruit weight of Milk thistle (Silybum marianum L. Gaernt.). In ancient Greece and Romania, physicians and herbalists used the Silybum marianum to treat a range of liver diseases. Besides their hepatoprotective action, silymarin flavonolignans have many other healthy properties, such as anti-platelet and anti-inflammatory actions. The aim of this study was to evaluate the toxic effect of flavonolignans on blood platelets, peripheral blood mononuclear cells (PBMCs) and human lung cancer cell line-A549-using different molecular techniques. We established that three major flavonolignans: silybin, silychristin and silydianin, in concentrations of up to 100 µM, have neither a cytotoxic nor genotoxic effect on blood platelets, PMBCs and A549. We also saw that silybin and silychristin have a protective effect on cellular mitochondria, observed as a reduction of spontaneous mitochondrial DNA (mtDNA) damage in A549, measured as mtDNA copies, and mtDNA lesions in ND1 and ND5 genes. Additionally, we observed that flavonolignans increase the blood platelets' mitochondrial membrane potential and reduce the generation of reactive oxygen species in blood platelets. Our current findings show for the first time that the three major flavonolignans, silybin, silychristin and silydianin, do not have any cytotoxicity and genotoxicity in various cellular models, and that they actually protect cellular mitochondria. This proves that the antiplatelet and anti-inflammatory effect of these compounds is part of our molecular health mechanisms.

Silybin, a Major Bioactive Component of Milk Thistle (Silybum marianum L. Gaernt.)-Chemistry, Bioavailability, and Metabolism

Milk thistle (Silybum marianum) is a medicinal plant that has been used for thousands of years as a remedy for a variety of ailments. The main component of S. marianum fruit extract (silymarin) is a flavonolignan called silybin, which is not only the major silymarin element but is also the most active ingredient of this extract, which has been confirmed in various studies. This compound belongs to the flavonoid group known as flavonolignans. Silybin's structure consists in two main units. The first is based on a taxifolin, the second a phenyllpropanoid unit, which in this case is conyferil alcohol. These two units are linked together into one structure by an oxeran ring. Since the 1970s, silybin has been regarded in official medicine as a substance with hepatoprotective properties. There is a large body of research that demonstrates silybin's many other healthy properties, but there are still a lack of papers focused on its molecular structure, chemistry, metabolism, and novel form of administration. Therefore, the aim of this paper is a literature review presenting and systematizing our knowledge of the silybin molecule, with particular emphasis on its structure, chemistry, bioavailability, and metabolism.

Phytosomal curcumin: A review of pharmacokinetic, experimental and clinical studies

Curcumin, a hydrophobic polyphenol, is the principal constituent extracted from dried rhizomes of Curcuma longa L. (turmeric). Curcumin is known as a strong anti-oxidant and anti-inflammatory agent that has different pharmacological effects. In addition, several studies have demonstrated that curcumin is safe even at dosages as high as 8g per day; however, instability at physiological pH, low solubility in water and rapid metabolism results in a low oral bioavailability of curcumin. The phytosomal formulation of curcumin (a complex of curcumin with phosphatidylcholine) has been shown to improve curcumin bioavailability. Existence of phospholipids in phytosomes leads to specific physicochemical properties such as amphiphilic nature that allows dispersion in both hydrophilic and lipophilic media. The efficacy and safety of curcumin phytosomes have been shown against several human diseases including cancer, osteoarthritis, diabetic microangiopathy and retinopathy, and inflammatory diseases. This review focuses on the pharmacokinetics as well as pharmacological and clinical effects of phytosomal curcumin.

Size restricted silymarin suspension evokes integrated adaptive response against acute hypoxia exposure in rat lung

Despite its extraordinary antioxidant capacity, the clinical usage of silymarin has remained restricted to amelioration of hepatic pathology. Perhaps its low bioavailability and uneven bio-distribution, owing to its poor aqueous solubility, are two main causes that have dampened the clinical applicability and scope of this preparation. We took these two challenges and suggested an unexplored application of silymarin. Apart from liver, two of the most susceptible vital organs at the highest risk of oxidative stress are brain and lung, especially during reduced oxygen saturation (hypoxia) at anatomical level. Hypoxia causes excess generation of radicals primarily in the lungs as it is the first organ at the interphase of atmosphere and organism making it the most prone and vulnerable to oxidative stress and the first responder against hypobaric hypoxia. As our first objective, we improved the silymarin formulation by restricting its size to the lower threshold and then successfully tested the prophylactic and therapeutic action in rat lung challenged with simulated hypobaric hypoxia. After dose optimization, we observed that 50mg/kg BW silymarin as size restricted and homogenous aqueous suspension successfully minimized the reactive oxygen species and augmented the antioxidant defense by significant upregulation of catalase and superoxide dismutase and reduced glutathione. Moreover, the well-established hypoxia markers and proteins related to hypoxia adaptability, hif1a and VEGF were differentially regulated conferring significant reduction in the inflammation caused by hypobaric hypoxia. We therefore report,the unexplored potential benefits of silymarin for preventing high altitude associated pathophysiology further paving its road to clinical trials.

Silymarin and Its Role in Chronic Diseases

Silymarin is the active constituent of Silybum marianum (milk thistle) which is a C-25 containing flavonolignan. Milk thistle has a lot of traditional values, being used as a vegetable, as salad, as bitter tonic, and as galactogogue in nursing mothers and in various ailments such as liver complications, depression, dyspepsia, spleenic congestions, varicose veins, diabetes, amenorrhea, uterine hemorrhage, and menstrual problems. In this present chapter, a comprehensive attempt has been made to discuss the potential of silymarin in chronic disorders. An insight into modulation of cellular signaling by silymarin and its implication in various disorders such as liver disorders, inflammatory disorders, cancer, neurological disorders, skin diseases, and hypercholesterolemia is being provided.

Preparation and characterization of magnetic nanoparticles and their impact on anticancer drug binding and release processes moderated through a 1sttier dendrimer

MNPs show superparamagnetic character which moderates the structural ability of TTDMM to bind silibinin (SB) and methotrexate (MTX) anticancer drugs for their potential use in drug delivery systems.

Positive Effects of Different Drug Forms of Silybin in the Treatment of Metabolic Syndrome

Silymarin and silybin are widely used for their hepatoprotective properties. Our previous studies confirm positive effect of silymarin on lipoprotein profile and lipid homeostasis. Advanced drug forms may improve the bioavailability of these compounds. In this study, we investigate the effects of silybin in different drug forms (standardized silybin, micronized silybin, and silybin in form of phytosomes) on dyslipidemia and glucose metabolism in hereditary hypertriglyceridemic (HHTg) rats. Male HHTg rats were divided into four groups of seven animals and were fed by experimental diets. Silybin significantly decreased serum level of triglycerides in groups of rats fed by standardized silybin and silybin in form of phytosomes compared to control group. Results show that silybin did not affect the total cholesterol level, but significantly increased the levels of HDL cholesterol in all groups of animals. Silybin in a standardized form had the highest hypotriglyceridemic effect. On the other hand, the micronized form has caused the highest increase of protective HDL and most significantly decreased glucose and insulin levels. Our results suggest that silybin is probably responsible for some positive properties of silymarin. Subsequent dose-dependent studies of silybin action may reveal the intensity of its positive effects on lipid and glucose parameters.

Serum and tissue pharmacokinetics of silibinin after per os and i.v. administration to mice as a HP-β-CD lyophilized product

Silibinin, the main active component of Silybum marianum is a hepatoprotective and antioxidant agent with antitumor effect, exhibiting very low aqueous solubility and oral bioavailability limiting its use in therapeutics. We characterized serum and tissue pharmacokinetics of SLB, calculated its absolute bioavailability and developed an open loop physiologically based pharmacokinetic (PBPK) model, after oral (per os, p.o) and intravenous (i.v.) administration in mice as water-soluble silibinin-hydroxypropyl-beta-cyclodextrin (SLB-HP-β-CD) lyophilized product. 60 C57Bl/6J mice were divided into groups of 5, each group representing one sampling time point. SLB-HP-β-CD lyophilized product was administered orally (50mg/kg) and i.v. (20mg/kg) after reconstitution with water for injection. Blood and tissue samples were collected at selected time points after animal sacrificed, properly treated and analyzed with HPLC-PDA for non-metabolized and total SLB. NONMEM pharmacokinetic analysis revealed a 2-compartment PK model to describe serum SLB pharmacokinetics, with zero order absorption after oral administration and was applied as forcing function to an open loop PBPK model incorporating heart, liver, kidneys and lungs. Tissue/plasma Kp values were estimated using i.v. data and can be used to predict tissue SLB distribution after oral administration. Absolute oral bioavailability of SLB from the lyophilized SLB-HP-β-CD product was 10 times higher than after administration of pure SLB.

Silibinin meglumine, a water-soluble form of milk thistle silymarin, is an orally active anti-cancer agent that impedes the epithelial-to-mesenchymal transition (EMT) in EGFR-mutant non-small-cell lung carcinoma cells

Silibinin is the primary active constituent of a crude extract (silymarin) from milk thistle plant (Silybum marianum) seeds. We explored the ability of an oral milk thistle extract formulation that was enriched with a water-soluble form of silibinin complexed with the amino-sugar meglumine to inhibit the growth of non-small-cell lung carcinoma (NSCLC) mouse xenografts. As a single agent, oral silibinin meglumine notably decreased the overall volumes of NSCLC tumors as efficiently as did the EGFR tyrosine kinase inhibitor (TKI) gefitinib. Concurrent treatment with silibinin meglumine impeded the regrowth of gefitinib-unresponsive tumors, resulting in drastic tumor growth prevention. Because the epithelial-to-mesenchymal transition (EMT) is required by a multiplicity of mechanisms of resistance to EGFR TKIs, we evaluated the ability of silibinin meglumine to impede the EMT in vitro and in vivo. Silibinin-meglumine efficiently prevented the loss of markers associated with a polarized epithelial phenotype as well as the de novo synthesis of proteins associated with the mesenchymal morphology of transitioning cells. Our current findings with this non-toxic, orally active, and water-soluble silibinin formulation might facilitate the design of clinical trials to test the administration of silibinin meglumine-containing injections, granules, or beverages in combination with EGFR TKIs in patients with EGFR-mutated NSCLC.

Site-specific inhibitory mechanism for amyloid β42 aggregation by catechol-type flavonoids targeting the Lys residues

The aggregation of the 42-residue amyloid β-protein (Aβ42) is involved in the pathogenesis of Alzheimer disease (AD). Numerous flavonoids exhibit inhibitory activity against Aβ42 aggregation, but their mechanism remains unclear in the molecular level. Here we propose the site-specific inhibitory mechanism of (+)-taxifolin, a catechol-type flavonoid, whose 3',4'-dihydroxyl groups of the B-ring plays a critical role. Addition of sodium periodate, an oxidant, strengthened suppression of Aβ42 aggregation by (+)-taxifolin, whereas no inhibition was observed under anaerobic conditions, suggesting the inhibition to be associated with the oxidation to form o-quinone. Because formation of the Aβ42-taxifolin adduct was suggested by mass spectrometry, Aβ42 mutants substituted at Arg(5), Lys(16), and/or Lys(28) with norleucine (Nle) were prepared to identify the residues involved in the conjugate formation. (+)-Taxifolin did not suppress the aggregation of Aβ42 mutants at Lys(16) and/or Lys(28) except for the mutant at Arg(5). In addition, the aggregation of Aβ42 was inhibited by other catechol-type flavonoids, whereas that of K16Nle-Aβ42 was not. In contrast, some non-catechol-type flavonoids suppressed the aggregation of K16Nle-Aβ42 as well as Aβ42. Furthermore, interaction of (+)-taxifolin with the β-sheet region in Aβ42 was not observed using solid-state NMR unlike curcumin of the non-catechol-type. These results demonstrate that catechol-type flavonoids could specifically suppress Aβ42 aggregation by targeting Lys residues. Although the anti-AD activity of flavonoids has been ascribed to their antioxidative activity, the mechanism that the o-quinone reacts with Lys residues of Aβ42 might be more intrinsic. The Lys residues could be targets for Alzheimer disease therapy.

Enhanced oral bioavailability and tissue distribution of a new potential anticancer agent, Flammulina velutipes sterols, through liposomal encapsulation

This study innovatively investigated the anticancer effect of Flammulina velutipes sterols (FVSs), the in vivo pharmacokinetics, and the tissue distribution of FVS-loaded liposomes. The FVS consisting of mainly 54.8% ergosterol and 27.9% 22,23-dihydroergosterol exhibited evident in vitro antiproliferative activity (liver HepG-2, IC50 = 9.3 μg mL(-1); lung A549, IC50 = 20.4 μg mL(-1)). To improve the poor solubility of FVS, F. velutipes sterol liposome (FVSL) was originally prepared. The encapsulation efficiency of ergosterol was 71.3 ± 0.1% in FVSL, and the encapsulation efficiency of 22,23-dihydroergosterol was 69.0 ± 0.02% in FVSL. In comparison to its two free sterol counterparts, the relative bioavailability of ergosterol and 22,23-dihydroergosterol in FVSL was 162.9 and 244.2%, respectively. After oral administration in Kunming mice, the results of tissue distribution demonstrated that the liposomal FVS was distributed mostly in liver and spleen. The drug was eliminated rapidly within 4 h. These findings support the fact that FVS, a potential nutraceutical and an effective drug for the treatment of liver cancer, could be encapsulated in liposomes for improved solubility and bioavailability.

Preparation of a nanoscale baohuoside I-phospholipid complex and determination of its absorption: in vivo and in vitro evaluations

Background

Baohuoside I is a potential anticancer drug for a variety of malignancies and has been approved for in vitro use. However, baohuoside I has very poor oral absorption.

Methods

In the present study, we prepared baohuoside I-phospholipid complexes of different diameters and determined their physicochemical properties using transmission electron microscopy, ultraviolet spectroscopy, and differential scanning calorimetry. The in vitro absorption of baohuoside I and baohuoside I-phospholipid complexes of different sizes were compared using the Caco-2 cell culture model, and subsequently, the bioavailability of baohuosidel and its complexes were estimated in vivo.

Results

Compared with the large-sized phospholipid complexes, a nanoscale phospholipid complex improved the oral bioavailability of baohuoside I. In addition, our results suggest that the smaller the particle size, the faster the complexes crossed the Caco-2 monolayer and the faster they were resorbed after oral administration in rats. The relative oral bioavailability of a nanoscale size 81 ± 10 nm baohuoside I-phospholipid complex (area under the concentration-time curve [AUC]^0–∞) was 342%, while that of baohuoside I and a 227.3 ± 65.2 μm baohuoside I-phospholipid complex was 165%.

Conclusion

We enhanced the oral bioavailability of baohuoside I by reducing the particle size of the phospholipid complex to the nanometer range, thereby improving its potential for clinical application.

Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy: a randomized controlled trial

CONTEXT

The botanical product silymarin, an extract of milk thistle, is commonly used by patients to treat chronic liver disease, despite scant and conflicting evidence of its efficacy.

OBJECTIVE

To determine the effect of silymarin on liver disease activity in patients with chronic hepatitis C virus (HCV) infection unsuccessfully treated with interferon-based therapy.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, double-blind, placebo-controlled trial conducted at 4 medical centers in the United States. Participants included 154 persons with chronic HCV infection and serum alanine aminotransferase (ALT) levels of 65 U/L or greater who were previously unsuccessfully treated with interferon-based therapy. Enrollment began in May 2008 and was completed in May 2010, with the last follow-up visit completed in March 2011.

INTERVENTION

Participants were randomly assigned to receive 420-mg silymarin, 700-mg silymarin, or matching placebo administered 3 times per day for 24 weeks.

MAIN OUTCOME MEASURES

The primary outcome measure was serum ALT level of 45 U/L or less (considered within the normal range) or less than 65 U/L, provided this was at least a 50% decline from baseline values. Secondary outcomes included changes in ALT levels, HCV RNA levels, and quality-of-life measures.

RESULTS

After 24 weeks of treatment, only 2 participants in each treatment group (P ≥ .99) met the primary outcome measure (3.8% [95% CI, 0.5% to 13.2%] for placebo, 4.0% [95% CI, 0.5% to 13.7%] for 420-mg silymarin, and 3.8% [95% CI, 0.5% to 13.2%] for 700-mg silymarin). The mean decline in serum ALT activity at the end of treatment did not differ significantly (P = .75) across the 3 treatment groups (mean decline, -4.3 [95% CI, -17.3 to 8.7] U/L for placebo, -14.4 [95% CI, -41.6 to 12.7] U/L for 420-mg silymarin, -11.3 [95% CI, -27.9 to 5.4] U/L for 700-mg silymarin); there likewise were no significant differences in HCV RNA levels (mean change, 0.07 [95% CI, -0.05 to 0.18] log10 IU/mL for placebo, -0.03 [95% CI, -0.18 to 0.12] log10 IU/mL for 420-mg silymarin, 0.04 [95% CI, -0.08 to 0.16] log10 IU/mL for 700-mg silymarin; P = .54) or quality-of-life measures. The adverse event profile of silymarin was comparable with that of placebo.

CONCLUSION

Higher than customary doses of silymarin did not significantly reduce serum ALT levels more than placebo in participants with chronic HCV infection unsuccessfully treated with interferon-based therapy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00680342.

Oral bioavailability of silymarin formulated as a novel 3-day delivery system based on porous silica nanoparticles

The purpose of this study was to develop porous silica nanoparticles (PSNs) as a carrier to improve oral bioavailability of poorly water-soluble drugs, using silymarin as a model. PSNs were synthesized by reverse microemulsion and ultrasonic corrosion methods. A 3-day release formulation consisting of a silymarin solid dispersion, a hydrophilic gel matrix and silymarin-loaded PSNs was prepared. In vitro release studies indicated that both the silymarin-loaded PSNs and the 3-day release formulation showed a typical sustained-release pattern over a long period, about 72 h. The in vivo studies revealed that the 3-day release formulation gave a significantly higher plasma concentration and larger area under the concentration-time curves than commercial tablets when orally administered to beagle dogs. This implies that the prepared 3-day release formulation significantly enhanced the oral bioavailability of silymarin, suggesting that PSNs can be used as promising drug carriers for oral sustained release systems. Thus providing a technically feasible approach for improving the oral bioavailability and long-term efficacy of poorly soluble drugs.

Expressions of P53 and CD68 in mouse liver with Schistosoma mansoni infection and the protective role of silymarin

Schistosomiasis is one of the major human parasitic diseases in many developing countries and is one of the causes of morbidity and mortality in the human population. The present work has been planned to study the histopathological and immunohistochemical expression of P53 and CD68 in mouse liver tissues experimentally infected with Schistosoma mansoni, in addition to the ameliorating role of silymarin. A total of 50 adult male mice were divided into 5 groups (10 animals each). Groups 1 and 2 were the control and silymarin groups, respectively, while group 3 was the infected group in which the mice were infected with S. mansoni live cercariae for 6 weeks. Groups 4 and 5 were the cotreated and posttreated groups, respectively, in which mice were infected with cercariae of S. mansoni and treated with silymarin during and after Schistosoma infection, respectively. The major histopathological lesions were variable numbers of perioval granulomas, diffuse infiltration of inflammatory cells, mainly eosinophils and small mononuclear cells, and fibrosis of portal areas and interlobular septa. Treatment with silymarin led to a significant reduction in granuloma area in all treated infected mice compared with nontreated infected mice. Immunohistochemical observations of the liver tissues showed a significant increase in the apoptotic proteins P53 and CD68 after the infection with the cercariae of Schistosoma, compared with the control group. The expression of the cytoplasmic P53 and CD68 was very low in the control liver sections. A significant decrease in the expression of the cytoplasmic P53 and CD68 was observed after silymarin treatment.

A new approach to enhance oral bioavailability of Silybum Marianum dry extract: association of mechanochemical activation and spray congealing

The aim of the work was to produce a delivery system for Silybum Marianum dry extract with enhanced oral bioavailability by combining two technologies (mechanochemical activation and spray congealing). Initially, the active was coground with sodium croscarmellose in a planetary mill in order to reach an activated state more prone to dissolution. DSC, XRD, FT-IR and LD analyses showed the formation of nanosized particles of dry extract, with reduced degree of crystallinity of the main crystalline flavolignans (silybine A and B). Then, microparticles containing the activated coground and, as comparison, the corresponding physical mixture of extract and polymer and the dry extract alone were produced by spray congealing technology using Gelucire(®) 50/13 as a hydrophilic low m.p. carrier. Microparticles containing the activated coground were produced spherical in shape, achieved satisfactory yield and high encapsulation efficiency. These microparticles, in addition to a favourable in vitro solubilisation kinetic, in a preliminary in vivo study in five rats demonstrated their ability to improve very significantly the oral bioavailability of the main flavolignans of Silybum Marianum dry extract (silybin A and B). These results suggested that the association of mechanochemical activation and spray congealing could be considered an innovative and very useful approach to the oral delivery of Silybum Marianum. Furthermore, for the first time the possibility of successfully applying the spray congealing technology for the preparation of a herbal drug delivery system was shown.