Emodin prevents intrahepatic fat accumulation, inflammation and redox status imbalance during diet-induced hepatosteatosis in rats

Pathophysiological Features of Rat Models of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is caused by various factors, including genetic and/or environmental factors, and has complicated pathophysiological features during the development of the disease. NAFLD/NASH is recognized as an unmet medical need, and NAFLD/NASH animal models are essential tools for developing new therapies, including potential drugs and biomarkers. In this review, we describe the pathological features of the NAFLD/NASH rat models, focusing on the histopathology of hepatic fibrosis. NAFLD/NASH rat models are divided into three categories: diet-induced, genetic, and combined models based on diet, chemicals, and genetics. Rat models of NASH with hepatic fibrosis are especially expected to contribute to the development of new therapies, such as drugs and biomarkers.

A Review on Bioactive Anthraquinone and Derivatives as the Regulators for ROS

Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development and utilization of anthraquinones as reactive oxygen species (ROS) regulators. In this review, a deep discussion was carried out on their antioxidant activities and the structure-activity relationships. The antioxidant mechanisms and the chemistry behind the antioxidant activities of both natural and synthesized compounds were furtherly explored and demonstrated. Due to the specific chemical activity of ROS, antioxidants are essential for human health. Therefore, the development of reagents that regulate the imbalance between ROS formation and elimination should be more extensive and rational, and the exploration of antioxidant mechanisms of anthraquinones may provide new therapeutic tools and ideas for various diseases mediated by ROS.

Emodin ameliorates matrix degradation and apoptosis in nucleus pulposus cells and attenuates intervertebral disc degeneration through LRP1 in vitro and in vivo

Low back pain (LBP) is the leading cause of disability worldwide, with a strong correlation to intervertebral disc degeneration (IDD). Inflammation-induced extracellular matrix (ECM) degradation plays a major role in IDD's progression. Emodin, known for its anti-inflammatory effects and ability to inhibit ECM degradation in osteoarthritis, but its role in IDD is unclear. Our study aimed to explore emodin's role and mechanisms on IDD both in vivo and in vitro. We discovered that emodin positively regulated anabolic markers (COL2A1, aggrecan) and negatively impacted catabolic markers (MMP3, MMP13) in nucleus pulposus cells, while also inhibiting cell apoptosis under inflammation environment. We revealed that emodin inhibits inflammation-induced NF-ĸB activation by suppressing the degradation of LRP1 via the proteasome pathway. Additionally, LRP1 was validated as essential to emodin's regulation of ECM metabolism and apoptosis, both in vitro and in vivo. Ultimately, we demonstrated that emodin effectively alleviates IDD in a rat model. Our findings uncover the novel pathway of emodin inhibiting ECM degradation and apoptosis through the inhibition of NF-κB via LRP1, thus alleviating IDD. This study not only broadens our understanding of emodin's role and mechanism in IDD treatment but also guides future therapeutic interventions.

Ex Vivo Model to Evaluate the Antibacterial and Anti-Inflammatory Effects of Gelatin-Tricalcium Phosphate Composite Incorporated with Emodin and Lumbrokinase for Bone Regeneration

Tricalcium phosphate (TCP) has gained attention due to its interconnected porous structures which promote fibrovascular invasion and bony replacement. Moreover, when gelatin is added and crosslinked with genipin (GGT), TCP exhibits robust biocompatibility and stability, making it an excellent bone substitute. In this study, we incorporated emodin and lumbrokinase (LK) into GGT to develop an antibacterial biomaterial. Emodin, derived from various plants, possesses antibacterial and anti-inflammatory properties. LK comprises proteolytic enzymes extracted from the earthworm Lumbricus rubellus and exhibits fibrinolytic activity, enabling it to dissolve biofilms. Additionally, LK stimulates osteoblast activity while inhibiting osteoclast differentiation. GGT was combined with emodin and lumbrokinase to produce the GGTELK composite. The biomedical effects of GGTELK were assessed through in vitro assays and an ex vivo bone defect model. The GGTELK composite demonstrated antibacterial properties, inhibiting the growth of S. aureus and reducing biofilm formation. Moreover, it exhibited anti-inflammatory effects by reducing the secretion of IL-6 in both in vivo cell experiments and the ex vivo model. Therefore, the GGTELK composite, with its stability, efficient degradation, biocompatibility, and anti-inflammatory function, is expected to serve as an ideal bone substitute.

Emodin Alleviates Lupus Nephritis in Rats by Regulating M1/M2 Macrophage Polarization

Lupus nephritis (LN) is one of the most common clinical manifestations of systemic lupus erythematosus (SLE), causing death and disability. The current research study explored whether there was any improvement effect on LN after emodin administration. Network pharmacology was used to screen the target genes of emodin for the treatment of LN. LPS and IL-4 were employed for RAW264.7 macrophage M1/M2 polarization induction, and 0.1% HgCl2 was used for the LN rat model’s establishment. Flow cytometry was performed to detect the effect of 20, 40, and 80 µM emodin on RAW264.7 macrophage polarization. HE and PAS staining were subsequently conducted to detect 70 mg/kg emodin action on renal injury in LN rats. The effect of emodin on the content of urinary proteins and dsDNA antibodies was also determined. The results indicated that peroxisome proliferators-activated receptors gamma (PPARG) may be a target gene of emodin in LN, and emodin had no significant toxicity to macrophages at different concentrations. Compared with the control, emodin significantly inhibited LPS-induced polarization in M1 macrophages and improved that of IL-4-induced M2 macrophages. Besides, emodin alleviated kidney injury and markedly reduced the levels of urinary protein and dsDNA antibodies in rats. Moreover, after targeting interference with the PPARG expression, the improvement effect of emodin on LN is significantly reduced, indicating that emodin may relieve the symptoms of LN by activating the PPARG expression. Our study revealed that PPARG may be applied as a new therapy for LN.

Emerging pharmaceutical therapeutics and delivery technologies for osteoarthritis therapy

Osteoarthritis (OA) is one of the most common joint degenerative diseases in the world. At present, the management of OA depends on the lifestyle modification and joint replacement surgery, with the lifespan of prosthesis quite limited yet. Effective drug treatment of OA is essential. However, the current drugs, such as the non-steroidal anti-inflammatory drugs and acetaminophen, as well as glucosamine, chondroitin sulfate, hyaluronic acid, are accompanied by obvious side effects, with the therapeutic efficacy to be enhanced. Recently, novel reagents such as IL-1 antagonists and nerve growth factor inhibitors have entered clinical trials. Moreover, increasing evidence demonstrated that active ingredients of natural plants have great potential for treating OA. Meanwhile, the use of novel drug delivery strategies may overcome the shortcomings of conventional preparations and enhance the bioavailability of drugs, as well as decrease the side effects significantly. This review therefore summarizes the pathological mechanisms, management strategies, and research progress in the drug molecules including the newly identified active ingredient derived from medicinal plants for OA therapy, with the drug delivery technologies also summarized, with the expectation to provide the summary and outlook for developing the next generation of drugs and preparations for OA therapy.

Identification and action mechanism of lipid regulating components from Rhei Radix et rhizoma

ETHNOPHARMACOLOGICAL RELEVANCE

Rhei Radix et Rhizoma is widely used in Traditional Chinese Medicine to attack stagnation, clear damp heat, relieve fire, cool blood, remove blood stasis and detoxify recorded in Chinese Pharmacopoeia. Modern pharmacological research has showed the extract of Rhei Radix et Rhizoma has the effect of lowering blood lipids, but the main active components and their mechanisms are still not clear.

AIM OF THE STUDY

To reveal the lipid regulating components from Rhei Radix et Rhizoma and preliminarily explore their related action mechanisms.

MATERIALS AND METHODS

A rat model of dyslipidemia was established by administration of a high-fat emulsion via gavage, and the intervention effect of different polar fractions of Rhei Radix et Rhizoma on rat blood lipids as well as their related action mechanisms were preliminarily investigated. The effective components were inferred based on the above tests and identified by high performance liquid chromatography in comparison with reference substances, their UV absorption and high resolution mass spectra characteristics.

RESULTS

The extract with dichloromethane fraction (DF) containing rhubarb free anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion) significantly regulated the disordered blood lipids, lowered TC and LDLC, reversed TG and increased HDLC level in dyslipidemic rats and also showed lipid-lowering effect on lipid abnormalities in HepG2 cells. DF could alter the signaling pathways such as PPARα and AMPK implicated in lipid metabolism, and it down-regulated the mRNA expression of liver APOA2, SCD-1, HMGCR, SREBP-2 and PCSK9, but up-regulated the expressions of liver APOE, LPL and intestinal ABCG8. Besides, it could change the composition of Firmicutes, Bacteroidetes and Proteobacteria in dyslipidemic rat feces samples.

CONCLUSIONS

Rhubarb free anthraquinones have a significant regulating effect on the levels of serum TC, LDLC and HDLC, and probably possess a bidirectional regulatory effect on TG level in dyslipidemic rats. These effects may be achieved by regulating the expressions of the liver PPARα and SREBP target genes, PCSK9 and the intestinal ABCG8 genes, which are involved in blood cholesterol transport, liver lipid metabolism and intestinal cholesterol excretion. Rhubarb free anthraquinones may also affect energy metabolism by changing the composition of gut microflora related to lipid metabolism in dyslipidemic rats.

Strategies for Biomaterial-Based Spinal Cord Injury Repair via the TLR4-NF-κB Signaling Pathway

The repair and motor functional recovery after spinal cord injury (SCI) has remained a clinical challenge. Injury-induced gliosis and inflammation lead to a physical barrier and an extremely inhibitory microenvironment, which in turn hinders the recovery of SCI. TLR4-NF-κB is a classic implant-related innate immunomodulation signaling pathway and part of numerous biomaterial-based treatment strategies for SCI. Numerous experimental studies have demonstrated that the regulation of TLR4-NF-κB signaling pathway plays an important role in the alleviation of inflammatory responses, the modulation of autophagy, apoptosis and ferroptosis, and the enhancement of anti-oxidative effect post-SCI. An increasing number of novel biomaterials have been fabricated as scaffolds and carriers, loaded with phytochemicals and drugs, to inhibit the progression of SCI through regulation of TLR4-NF-κB. This review summarizes the empirical strategies for the recovery after SCI through individual or composite biomaterials that mediate the TLR4-NF-κB signaling pathway.

Time-Dependent Changes in Hepatic Sphingolipid Accumulation and PI3K/Akt/mTOR Signaling Pathway in a Rat Model of NAFLD

Increased lipid bioavailability in a diet favors lipid accumulation, enhancing hepatic lipotoxicity and contributing to insulin resistance (IR) development. The aim of our study was to examine time-dependent alterations in the intrahepatic content of sphingolipids and insulin signaling pathway in rats fed a high-fat diet (HFD). The experiment was conducted on male Wistar rats receiving a standard diet or HFD for five weeks. At the end of each experimental feeding week, liver sphingolipids were determined using high-performance liquid chromatography. The expression of proteins from the sphingolipid pathway and glucose transporter expression were assessed by Western blot. The content of phosphorylated form of proteins from the insulin pathway was detected by a multiplex assay kit. Our results revealed that HFD enhanced hepatic ceramide deposition by increasing the expression of selected proteins from sphingomyelin and salvage pathways in the last two weeks. Importantly, we observed a significant inhibition of Akt phosphorylation in the first week of HFD and stimulation of PTEN and mTOR phosphorylation at the end of HFD. These changes worsened the PI3K/Akt/mTOR signaling pathway. We may postulate that HFD-induced reduction in the insulin action in the time-dependent matter was exerted by excessive accumulation of sphingosine and sphinganine rather than ceramide.

Emodin - A natural anthraquinone derivative with diverse pharmacological activities

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural anthraquinone derivative that is present in numerous globally renowned herbal medicines. It is recognised as a protein tyrosine kinase inhibitor and as an anticancer drug, active against various tumour cells, including lung, breast, liver, and ovarian cancer cells. Recently, its role in combination chemotherapy with various allopathic medicines, to minimize their toxicity and to enhance their efficacy, has been studied. The use of emodin in these therapies is gaining popularity, due to fewer associated side effects compared with standard anticancer drugs. Emodin has a broad therapeutic window, and in addition to its antineoplastic activity, it displays anti-ulcer, anti-inflammatory, hepatoprotective, neuroprotective, antimicrobial, muscle relaxant, immunosuppressive and antifibrotic activities, in both in vitro and in vivo models. Although reviews on the anticancer activity of emodin have been published, none coherently unite all the pharmacological properties of emodin, particularly the anti-oxidant, antimicrobial, antidiabetic, immunosuppressive and hepatoprotective activities of the compound. Hence, in this review, all of the available data regarding the pharmacological properties of emodin are explored, with particular emphasis on the modes of action of the molecule. In addition, the manuscript details the occurrence, biosynthesis and chemical synthesis of the compound, as well as its toxic effects on biotic systems.

Experimental anti-tumor effect of emodin in suspension - in situ hydrogels formed with self-assembling peptide

Lung cancer is a major cause of cancer-related deaths worldwide. Stimulus-sensitive hydrogels, which can be formed by responding to stimuli in the cancer microenvironment, have been widely studied as controlled-release carriers for hydrophobic anticancer drugs. In this study, self-assembling peptide RADA16-I was used to encapsulate the hydrophobic drug emodin (EM) under magnetic stirring to form a colloidal suspension, and the colloidal suspension (RADA16-I-EM) was introduced into environments with physiological pH/ionic strength to form hydrogels in situ. The results showed that RADA16-I had good cell compatibility and the RADA16-I-EM in situ hydrogels can obviously reduce the toxicity of EM to normal cells. In addition, compared with free EM (in water suspensions without peptide) at equivalent concentrations, RADA16-I-EM in situ hydrogels significantly reduced the survival fraction of LLC lung cancer cells, while increased the uptake of EM by the cells, and it also induced apoptosis and cell cycle arrest in the G2/M phase more significantly and reduced the migration, invasion, and clone abilities of the cells in vitro. The RADA16-I-EM in situ hydrogels also showed better cancer growth inhibition effects in cancer models (mice bearing LLC cells xenograft cancer), which induced cell apoptosis in the cancer tissue and reduced the toxic side effects of EM on normal tissues and organs in vivo compared with the free EM. It was revealed that RADA16-I can be exploited as a promising carrier for hydrophobic anticancer drugs and has the potential to improve the administration of anticancer drugs to treat cancer effectively with enhanced chemotherapy.

A Pivotal Role of the Nrf2 Signaling Pathway in Spinal Cord Injury: A Prospective Therapeutics Study

The nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway has a main role against oxidative stress and inflammation. Spinal Cord Injury (SCI) leads to the high secretion of inflammatory cytokines and reactive oxygen species, which disturbs nervous system function and regeneration. Several studies have indicated that the activation of the Nrf2 signaling pathway may be effective against inflammation after SCI. The experimental studies have indicated that many chemical and natural agents act as Nrf2 inducer, which inhibits the SCI progression. Thus, the finding of novel Nrf2- inducer anti-inflammatory agents may be a valuable approach in drug discovery. In the present review, we discussed the Nrf2 signal pathway and crosstalk with the NF-κB pathway and also the impact of this pathway on inflammation in animal models of SCI. Furthermore, we discussed the regulation of Nrf2 by several phytochemicals and drugs, as well as their effects on the SCI inhibition. Therefore, the current study presented a new hypothesis of the development of anti-inflammatory agents that mediate the Nrf2 signaling pathway for treating the SCI outcomes.

Emodin protects knee joint cartilage in rats through anti-matrix degradation pathway: An in vitro and in vivo study

AIMS

Osteoarthritis (OA) is a common joint disease and the main cause of disability. We sought to determine the effective concentration of emodin on chondrocytes and to identify the dosage of emodin that induces a comparable therapeutic effect with the COX-2 inhibitor drug, celecoxib that is currently used to treat OA.

MATERIAL AND METHODS

In vitro experiments induced inflammation of chondrocytes by IL-1β, and an osteoarthritis model was established in vivo by cutting rat anterior cruciate ligament. Western Blot, Real-time PCR, HE staining, Safranin O-green staining and immunohistochemistry were performed to detect MMP-3, MMP-13, ADAMTS-4, iNOS and COL2A1 on the chondrocytes or the tibial plateau. The cytokine activity and content in serum of six groups of rats were measured by kit.

RESULTS

It was found that the surface layer of the cartilage was thicker and smoother after the administration of emodin. Tissue expression of MMP-3, MMP-13, ADAMTS-4 and iNOS were significantly (p < 0.05) decreased in chondrocytes and cartilage treated with different doses of emodin, and the content of COL2A1 was reversed. Emodin also significantly decreased the blood levels of COX-2 and PGE2. The effective emodin in vitro was 5 μmol/L, whereas emodin at 80 mg/kg was equivalent to celecoxib in vivo.

CONCLUSION

Emodin reduces the expression of cartilage matrix degradation biomarkers, thereby reducing the degradation of cartilage matrix and protecting the knee joint cartilage. Emodin at 5 μmol/L shows the best concentration to treat chondrocytes, and the protective effect of emodin at 80 mg/kg is comparable to that of celecoxib.

Emodin attenuates silica-induced lung injury by inhibition of inflammation, apoptosis and epithelial-mesenchymal transition

Silicosis is a fatal pulmonary disease caused by the inhalation of silica dust, and characterized by inflammation and fibrosis of the lung, with no effective treatment to date. Here we investigate the effect of emodin, an anthraquinone derivative isolated from rhubarb using a mouse silicosis model and in vitro cultured human macrophages and alveolar epithelial cells. Results from histological examination indicated that emodin reduced the degree of alveolitis and fibrosis in the lungs of mice exposed to silica particles. We also demonstrated that emodin effectively inhibited the phosphorylation of Smad3 and NF-κB and reduced the levels of inflammatory factors in the lung tissue of mice treated with silica particles. In addition, we found that emodin inhibited apoptosis and demonstrated an anti-fibrotic effect by down-regulating the pro-apoptotic protein Bax and up-regulating the anti-apoptotic protein Bcl-2. Furthermore, emodin increased E-cadherin levels, reduced the expression of Vimentin, α-SMA and Col-I, as well as pro-inflammatory factors TGF-β1, TNF-α and IL-1β in vivo and in vitro. These results suggested that emodin can regulate epithelial-mesenchymal transition (EMT) through the inhibition of the TGF-β1/Smad3 signaling pathway and the NF-κB signaling pathway to prevent alveolar inflammation and apoptotic process. Overall, this study showed that emodin can alleviate pulmonary fibrosis in silicosis through regulating the inflammatory response and fibrotic process at multiple levels.

Emodin protected against synaptic impairment and oxidative stress induced by fluoride in SH-SY5Y cells by modulating ERK1/2/Nrf2/HO-1 pathway

Excessive fluoride exposure contributes to neurotoxic effects. Emodin exhibits antioxidative functions in the central nervous system (CNS); however, its neuroprotective mechanism against fluoride remains to be elucidated. Our aim was to explore the neuroprotective efficacy and the possible mechanisms of emodin. In our study, synaptic proteins and oxidative stress damage were examined after human neuroblastoma SH-SY5Y cells were treated with high doses of NaF for 24 hours. Moreover, pretreatment with emodin was used to shed light on the neuroprotective effects in NaF-induced toxicity in SH-SY5Y cells. We found that NaF significantly lowered the protein expressions of SNAP 25, synaptophysin and PSD 95 in SH-SY5Y cells. In addition, NaF exposure increased the protein expression of p-ERK1/2 and decreased the protein expressions of Nrf2 and HO-1, as well as facilitated increasing ROS, 4-hydroxynonenal (4-HNE), and 8-Hydroxy-2'-deoxyguanosine (8-OHdG). Pretreatment with emodin significantly recovered these alterations caused by NaF. These data implied that the neuroprotective effects of emodin and pointed to the promising utilization for protecting against neurotoxicity induced by fluoride.

Quinones as preventive agents in Alzheimer's diseases: focus on NLRP3 inflammasomes

OBJECTIVES

Alzheimer's disease (AD) is a hidden neurological degenerative disease, which main clinical manifestations are cognitive dysfunction, memory impairment and mental disorders. Neuroinflammation is considered as a basic response of the central nervous system. NLRP3 (Nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3) inflammasome is closely related to the occurrence of neuroinflammation. Activation of the NLRP3 inflammasome results in the release of cytokines, pore formation and ultimately pyroptosis, which has demonstrated one of the critical roles in AD pathogenesis. Inhibition of the activity of NLRP3 is one of the focuses of the research. Therefore, NLRP3 represents an attractive pharmacological target, and discovery compounds with good NLRP3 inhibitory activity are particularly important.

KEY FINDINGS

Quinones have good neuroprotective effects and prevent AD, which may be related to their regulation of inflammatory response. The molecular docking was used to explore 12 quinones with AD prevention and treatment and NLRP3. Docking results showed that the combination of anthraquinones and NLRP3 were the best, and the top two chemical compounds were Purpurin and Rhein, which are the most promising NLRP3 inhibitors.

SUMMARY

These quinones may provide the theoretical basis for finding lead compounds for novel neuroprotective agents.

The effect of emodin on liver disease -- comprehensive advances in molecular mechanisms

Liver injury could be caused by a variety of causes, including alcohol, drug poisoning, autoimmune overreaction, etc. In the period of liver injury, hepatic stellate cells (HSCs) will be activated and produce excessive extracellular matrix (ECM). If injury cannot be suppressed, liver injury will develop into fibrosis, even cirrhosis and liver cancer. It is reported that some monomer components extracted from traditional Chinese medicine have better effects on protecting liver. Emodin, an anthraquinone compound extracted from the traditional Chinese medicine RHEI RADIX ET RHIZOMA, has anti-inflammatory, antioxidant, liver protection and anti-cancer effects, and can prevent liver injury induced by a variety of factors. By searching literatures related to the liver protection of emodin in PUBMED, SINOMED, EBM and CNKI databases, it was found that emodin could inhibit the production and promote the secretion of bile acids, and have a protective effect on intrahepatic cholestasis. Also, emodin reduce collagen synthesis and anti-hepatic fibrosis by inhibiting oxidative stress, TGF-β/Smad pathway and HSCs proliferation, and promoting apoptosis of HSCs. Emodin can also regulate lipid metabolism and regulate the synthesis and oxidation of lipids and cholesterol to protect the nonalcoholic fatty liver. Besides, emodin can induce the apoptosis of hepatocellular carcinoma cells by acting on the death receptor pathway and mitochondrial apoptosis pathway, thus inhibiting the development of hepatocellular carcinoma. Moreover, emodin can modulate immunity and improve immune rejection in liver transplantation animals. In conclusion, emodin has a good effect on liver protection, but further experimental data are needed to verify it.

A Candidate Drug for Nonalcoholic Fatty Liver Disease: A Review of Pharmacological Activities of Polygoni Multiflori Radix

Nonalcoholic fatty liver disease, a type of metabolic syndrome, continues to rise globally. Currently, there is no approved drug for its treatment. Improving lifestyle and exercise can alleviate symptoms, but patients' compliance is poor. More and more studies have shown the potential of Polygoni Multiflori Radix (PMR) in the treatment of NAFLD and metabolic syndrome. Therefore, this paper reviews the pharmacological effects of PMR and its main chemical components (tetrahydroxystilbene glucoside, emodin, and resveratrol) on NAFLD. PMR can inhibit the production of fatty acids and promote the decomposition of triglycerides, reduce inflammation, and inhibit the occurrence of liver fibrosis. At the same time, it maintains an oxidation equilibrium status in the body, to achieve the therapeutic purpose of NAFLD and metabolic syndrome. Although more standardized studies and clinical trials are needed to confirm its efficacy, PMR may be a potential drug for the treatment of NAFLD and its complications. However, the occurrence of adverse reactions of PMR has affected its extensive clinical application. Therefore, it is necessary to further study its toxicity mechanism, enhance efficacy and control toxicity, and even reduce toxicity, which will contribute to the safe clinical use of PMR.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

Emodin ameliorates metabolic and antioxidant capacity inhibited by dietary oxidized fish oil through PPARs and Nrf2-Keap1 signaling in Wuchang bream (Megalobrama amblycephala)

Dietary lipids and fatty acids are involved in cell metabolism and animal physiological regulation. However, oxidized lipids could induce oxidative stress and disorder normal growth and physiological health in fish. A 12-week rearing experiment with 6% fish oil (6F), 6% oxidized fish oil (6OF) and emodin supplemented diets (6F + E, 6OF + E) was conducted to evaluate the protective mechanism of emodin on oxidized fish oil stress in Megalobrama amblycephala. Results indicate that, under oxidized fish oil stress, emodin rescued the growth performance inhibition, improved special growth ratio (SGR), and reduced feed conversion ratio (FCR) and hepatosomatic index (HSI); rescued intestine histological impairment, ameliorated the structural expansion and membrane damage of mitochondria in intestine cells, and increased the length and intensity of intestinal villus. Moreover, emodin enhanced serum immune and antioxidant enzyme activity, increased metabolic activity through PPARs signaling, increased antioxidant capacity through PPARs and Nrf2-Keap1 signaling based on the transcriptional expression of specific genes. These results indicate emodin could be used as an effective immunostimulant to protect organism form oxidative stress induced by dietary oxidized lipid. This may provide insights for oxidized lipid prevention in aquaculture production.

Polygonum cuspidatum extract attenuates fructose-induced liver lipid accumulation through inhibiting Keap1 and activating Nrf2 antioxidant pathway

BACKGROUND

Polygonum cuspidatum has been used in traditional Chinese medicine to treat liver disorders associated with oxidative stress, inflammation and lipid accumulation for centuries in patients.

PURPOSE

The aim of this study was to examine whether P. cuspidatum extract (PCE) prevented against fructose-induced liver lipid accumulation via regulating Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway.

METHOD

PCE was administered orally to male Sprague-Dawley rats given 10% fructose drinking water for 6 weeks at 80 and 160 mg/kg once daily for 11 weeks.

RESULTS

PCE significantly alleviated liver lipid accumulation in fructose-fed rats with metabolic syndrome. It also inhibited Keap1, activated Nrf2 antioxidant pathway, resulting in the suppression of oxidative stress, evidenced by reducing hydrogen peroxide (H₂O₂), malondialdehyde (MDA) and hydroxy radical (OH^•) levels, and increasing glutathione (GSH)/oxidized glutathione (GSSG) ratio as well as superoxidase dismutase (SOD) and catalase (CAT) activity in the liver of fructose-fed rats. Additionally, PCE up-regulated peroxisome proliferator activated receptor-α (PPAR-α), and down-regulated sterol regulatory element binging protein 1 (SREBP-1), fatty acid synthetase (FAS) and stearoyl-CoA desaturase-1 (SCD-1) in this animal model, being consistent with its reduction of triglyceride (TG) levels.

CONCLUSION

These results demonstrate that PCE reduces oxidative stress, and prevent lipid accumulation in the liver of fructose-fed rats possibly by targeting the Keap1/Nrf2 pathway. PCE may be a promising therapeutic strategy for fructose-associated liver lipid accumulation.

Pharmacological properties of Rheum turkestanicum Janisch

Medicinal herbs have been increasingly used worldwide for diseases prevention and treatment. Rheum turkestanicum Janisch. is a perennial shrub of the Polygonaceae family. Genus Rheum includes more than 60 species growing around the world which are used in foods and traditional medicines. R. turkestanicum is believed to be able to improve different kinds of disorders including diabetes, hypertension, jaundice and cancer. In recent years, this medicinal plant has been a subject of many experimental studies to document its health-beneficial properties. These studies have revealed antidiabetic, anticancer, nephroprotective, cardioprotective, and hepatoprotective properties of R. turkestanicum. The presence of flavonoids (e.g. epicatechin and quercetin) and anthraquinones (e.g. chrysophanol, physcion, and emodin) in R. turkestanicum justifies its health-beneficial effects. Nevertheless, possible therapeutic applications and safety of this plant still need to be elucidated in further clinical studies.

Health functions and structure-activity relationships of natural anthraquinones from plants

Anthraquinone compounds with the anthraquinone ring structure are widely found in traditional Chinese medicines and they are attracting a lot of attention due to their good pharmacological activity. Diversities of anthraquinones depend on their chemical structures, such as the number of anthraquinone rings and the substituents; what's more, the difference in chemical structure determines the difference in physiological activity. Based on results of previous studies, this review summarizes several natural anthraquinones identified from Chinese herbal medicines and their physiological activities including anti-cancer, anti-pathogenic microorganisms, anti-inflammatory, anti-oxidation, anti-osteoporosis, anti-depression, and anti-constipation. The source, effect, model, and action mechanism of the active anthraquinones are described in detail, from which their structure-activity relationship is summarized. By analyzing the relationship between anthraquinone structure and function, we found that, on the whole structure, the anthraquinone ring and anthraquinone glycosides have significant anticancer activity and anti-constipation activity, while for their substituents, anthraquinones substituted by alizarin have significant antioxidant activity and the polarity of the substituents is closely related to their antibacterial activities.

A Cell-Based Metabonomics Approach to Investigate the Varied Influences of Chrysophanol-8-O-β-D-Glucoside With Different Concentrations on L-02 Cells

In this study, the effects of different concentrations of chrysophanol-8-O-β-D-glucoside (C-8-O-β-D-glu) on L-02 liver cells were analyzed by high content analysis (HCA) and metabonomics to explore the potential mechanism involved. The results showed that low concentrations (12 and 24 μM) of C-8-O-β-D-glu increased the cells viability significantly, while high concentration (96 μM) showed significant cytotoxicity on L-02 cells. HCA was applied to analyze the changes of nuclei and mitochondria after the cells being exposed to C-8-O-β-D-glu for 24 h. The results showed high concentration (96 μM) of C-8-O-β-D-glu significantly reduced the number of living cells, increased average nucleus area, DNA content and mitochondrial membrane potential (MMP). Then non-target metabonomics was carried out to identify potential biomarkers and metabolic pathways of L-02 cells impacted by C-8-O-β-D-glu. Eleven important potential biomarkers associated with four metabolic pathways were identified in this analysis. Dysregulation of alanine, aspartate and glutamate metabolism were observed in both LCG and HCG. In addition, low concentration (24 μM) of C-8-O-β-D-glu would impact arginine and proline metabolism. High concentration (96 μM) of C-8-O-β-D-glu would impact phenylalanine metabolism and beta-alanine metabolism. Alanine, aspartate and glutamate metabolism, arginine and proline metabolism, phenylalanine metabolism, beta-alanine metabolism were involved in different effects of C-8-O-β-D-glu on L-02 cells.

Emodin ameliorates cartilage degradation in osteoarthritis by inhibiting NF-κB and Wnt/β-catenin signaling in-vitro and in-vivo

The overproduction of MMPs (matrix metalloproteinases) and members of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) protein family plays an important role in the pathogenesis of osteoarthritis (OA). The potential of selective MMPs or ADAMTS inhibitors as chemopreventive agents for OA has been demonstrated in several studies. In this study, we investigated the protective effects of emodin (1,3,8-trihydroxy-6-methylanthaquinone), isolated from the root of Rheum palmatum L., in the inhibition of MMP and ADAMTS expression in both rat chondrocytes and an animal model of OA. The expression of MMP-3, MMP-13, ADAMTS-4, ADAMTS-5, aggrecan, and collagen II mRNA and protein in interleukin-1beta (IL-1β)-induced rat chondrocytes was followed by quantitative real-time PCR and western blot. The activation of the NF-κB and Wnt/β-catenin pathways by IL-1β was assessed by western blot. The in vivo effects of emodin were evaluated by intra-articular injection in rats in an experimental model of OA induced by anterior cruciate ligament transection. Emodin dose-dependently down-regulated the expression of MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 at both the mRNA and protein level in IL-1β-stimulated rat chondrocytes. In addition, the IL-1β-induced activation of NF-κB and Wnt signals was attenuated by emodin, as determined by western blotting. The intra-articular injection of emodin in a rat OA model ameliorated OA progression, as determined in morphological and histological analyses in vivo. Taken together, our findings demonstrate that emodin is a promising therapeutic agent for the prevention and treatment of OA.

Emodin extends lifespan of Caenorhabditis elegans through insulin/IGF-1 signaling pathway depending on DAF-16 and SIR-2.1

The naturally occurring anthraquinone emodin has been serving primarily as an anti-bacterial and anti-inflammatory agent. However, little is known about its potential on anti-aging. This investigation examined the effect of emodin on lifespan and focused on its physiological molecular mechanisms in vivo. Using Caenorhabditis elegans (C. elegans) as an animal model, we found emodin could extend lifespan of worms and improve their antioxidant capacity. Our mechanistic studies revealed that emodin might function via insulin/IGF-1 signaling (IIS) pathway involving, specifically the core transcription factor DAF-16. Quantitative RT-PCR results illustrated that emodin up-regulated transcription of DAF-16 target genes which express antioxidants to promote antioxidant capacity and lifespan of worms. In addition, attenuated effect in sir-2.1 mutants suggests that emodin likely functioned in a SIR-2.1-dependent manner. Our study uncovers a novel role of emodin in prolonging lifespan and supports the understanding of emodin being a beneficial dietary supplement.

ROS/p38/p53/Puma signaling pathway is involved in emodin-induced apoptosis of human colorectal cancer cells

AIM

Emodin was found effective in suppressing proliferation of cancer cells including colorectal cancer (CRC), but the mechanisms were still unclear. This study was aimed to investigate the possible mechanism of emodin's anti-CRC effects.

METHODS

Two most frequently used CRC cell lines, SW480 and SW620, were investigated in this study. Serially diluted emodin solutions were used to incubate CRC cells. siRNAs were used to silence the expressions of p38 and Puma respectively. Intracellular ROS production was detected by DCFH-DA staining; proliferation and apoptosis of CRC cells were assessed by MTT assay and Hoechst staining respectively. Western blotting was applied to evaluate the activation of p38/p53/Puma signaling.

RESULTS

Both in SW480 and SW620 cells, emodin inhibited proliferation by inducing ROS-mediated apoptosis in a concentration-dependent manner. The p38/p53/Puma signaling was also activated after emodin incubation in a concentration-dependent manner. The ROS scavenger NAC, p38 silencing and Puma silencing impaired the anti-proliferation and apoptosis- inducing effects of emodin.

CONCLUSIONS

emodin inhibited proliferation of human CRC cells by inducing cell apoptosis by activating ROS/p38/p53/Puma signaling.

Anti-inflammatory effect of emodin on lipopolysaccharide-induced keratitis in Wistar rats

Emodin, a major bioactive extract of several Chinese herbs, has been shown to have a number of biological activities including antiviral, anti-inflammatory, anti-tumor, anti-fibrosis etc. In the present study, we investigated the effects of emodin as an anti-inflammatory agent on lipopolysaccharide (LPS) induced keratitis in Wistar rats. Clinical score, slit-lamp microscope were used to determine corneal inflammatory response. Corneal structure was observed by hematoxylin-eosin staining and transmission electron microscopy. Messenger ribonucleic acid levels of tight junction protein and cytokines were determined by reverse transcription- polymerase chain reaction. The activation of nuclear factor-kappa B (NF-κB) was detected with Western blot. We found that disorganized corneal tissue and cellular structures were observed in keratitis rats and emodin could deduce inflammatory response and improve corneal structure. Pretreated with emodin could up-regulate and down-regulate the mRNA expression of occludin and Interleukin-6. The activation of NF-κB could be inhibited partly after emodin treatment. In conclusion, emodin reduced corneal inflammation in LPS-induced keratitis in Wistar rats due to its capability of inhibition in NF-κB activation.

11β-HSD1 modulates LPS-induced innate immune responses in adipocytes by altering expression of PTEN

Inhibition of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) represents a therapeutic target for treating hyperglycemia in type 2 diabetes. Here, we investigate the effects of 11β-HSD1 on the innate immune response of adipocytes to produce proinflammatory cytokines. The 11β-HSD1 inhibitor emodin, or 11β-HSD1-targeted small interfering RNA, dose dependently suppressed IL-6, IL-1β, and TNF-α expression in lipopolysaccharide-treated 3T3-L1 adipocytes. Inhibiting 11β-HSD1 also reduced phosphatase and tensin homologue (PTEN) expression, a negative regulator of phosphatidylinositol 3-kinase effects, whereas 1pM cortisone or dexamethasone induced IL-6 and PTEN levels. PTEN-targeted small interfering RNA decreased IL-6, IL-1β, and TNF-α without affecting 11β-HSD1 levels. Correspondingly, emodin increased phosphorylated protein kinase B (p-PKB) (Ser473) to PKB ratio but not p-PKB (Thr308) to PKB ratio. Emodin did not increase the p-PKB (Ser473) to PKB ratio when the rapamycin-insensitive companion of mTOR was depleted, further supporting the involvement of mammalian target of rapamycin complex 2 in PKB phosphorylation. Moreover, emodin suppressed phosphorylated inhibitor of κB α (p-IκBα) to IκBα ratio and reduced nuclear factor κ B subunit p50 in the nuclear fraction. In contrast, 1pM cortisone or dexamethasone decreased p-PKB (Ser473) to PKB ratio, increased p-IκBα to IκBα ratio, and increased nuclear NF-κB subunit p50. Additionally, wortmannin had similar effects on IL-6, p-PKB (Ser473) to PKB ratio, and p-IκBα to IκBα ratio as 1pM cortisone or dexamethasone. Finally, emodin treatment of streptozotocin diabetic rats on a high-fat diet reduced levels of IL-6, PTEN, Cluster of Differentiation 68, and the ratio of p-IκBα to IκBα in visceral fat, indicating that our findings in vitro may also apply to visceral fat in vivo. Together, these results suggest that inhibiting 11β-HSD1 reduces lipopolysaccharide-induced proinflammatory innate immune responses in adipocytes by down-regulating PTEN expression, leading to activation of the PI3K/PKB pathway.

Emodin protects against diabetic cardiomyopathy by regulating the AKT/GSK-3β signaling pathway in the rat model

Diabetes mellitus (DM) has been recognized as a major health problem. Emodin (Emo) has been reported to exhibit protective effects against diabetic nephropathy. However, little has been known about the effect of Emo on diabetic cardiomyopathy (DCM). A type 2 DM model was induced in rats by low dose streptozotocin (STZ) combined with high energy intake. We found that Emo-treated groups displayed significantly higher body weight (BW) and lower heart weight (HW)/BW. Furthermore, Emo could significantly decrease blood glucose, total cholesterol (TG) levels, and triglyceride (TC) levels in diabetic rats. Moreover, the Emo-treated group showed a marked increase in heart rate (HR) and showed lower left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular posterior wall thickness (LWPWT), and interventricular septal diastolic wall thickness (IVSD). Emo induced a significant increase in phosphorylation of Akt and GSK-3β in myocardium. These results suggest that Emo may have great therapeutic potential in the treatment of DCM by Akt/GSK-3β signaling pathway.

Emodin ameliorated lipopolysaccharide-induced fulminant hepatic failure by blockade of TLR4/MD2 complex expression in D-galactosamine-sensitized mice

Emodin has been reported to possess anti-inflammatory and anti-oxidant activities. The aim of this study was to explore the effect and mechanism of emodin on lipopolysaccharide (LPS)-induced fulminant hepatic failure (FHF) in D-galactosamine (D-GalN)-sensitized mice. Our results showed that pretreatment with emodin inhibited the elevation of plasma aminotransferases, alleviated the hepatic histopathological abnormalities and improved the survival rate of LPS/D-GalN-primed mice. Moreover, emodin markedly attenuated the increased serum and hepatic tumor necrosis factor-α (TNF-α) production, and activated hepatic p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signal pathways in LPS/D-GalN-challenged mice. Furthermore, using an in vitro experiment, we found that emodin dose-dependently suppressed TNF-α production, dampened AP-1 and NF-κB activation, and blocked toll-like receptor (TLR) 4/myeloid differentiation factor (MD) 2 complex expression in LPS-elicited RAW264.7 mouse macrophage cells. Taken together, these data suggested that emodin could effectively prevent LPS-induced FHF, which might be mediated by inhibition of TNF-α production, deactivation of MAPKs and NF-κB, and blockade of TLR4/MD2 complex expression.

Preventing non-alcoholic fatty liver disease through Lactobacillus johnsonii BS15 by attenuating inflammation and mitochondrial injury and improving gut environment in obese mice

The increasing prevalence of obesity worldwide is associated with a parallel increase in non-alcoholic fatty liver disease (NAFLD). To investigate the effect of Lactobacillus johnsonii BS15 on NAFLD, 120 male ICR mice were randomly divided into four groups and administrated with BS15 (2 × 10(7) cfu/0.2 mL or 2 × 10(8) cfu/0.2 mL) or phosphate buffered saline (PBS) throughout a 17-week experimental period. The mice were fed with normal chow diet (NCD) 5 weeks before the experimental period. Afterward, with the exception of the PBS group, NCD was changed into high-fat diet (HFD) for the remaining experimental period. Results showed that BS15-treated HFD mice were protected from hepatic steatosis and hepatocyte apoptosis. BS15 exhibited a positive effect on liver lipid peroxidation through an anti-oxidative stress activity by enhancing the liver antioxidant defense system. In addition, BS15 inhibited the insulin resistance; decreased the mRNA levels of acetyl-CoA carboxylase 1, fatty acid synthase, and peroxisome proliferator-activated receptor γ; and increased the expression of the fasting-induced adipose factor in livers. Meanwhile, BS15 attenuated mitochondria abnormalities when the content of uncoupling protein-2 decreased and cytochrome c increased in NAFLD mice. BS15 also reduced the level of serum lipopolysaccharide in NAFLD mice by lowering the intestinal permeability and adjusting gut flora, followed by the downregulation of the TNFα mRNA level in liver and the serum level of C-reactive protein. These findings suggest that BS15 may be effective in preventing NAFLD induced by HFD.

Emodin attenuates systemic and liver inflammation in hyperlipidemic mice administrated with lipopolysaccharides

Non-alcoholic fatty liver disease (NAFLD) is a major epidemics of the modern societies and has an inflammatory component in the pathogenesis. However, approved anti-inflammatory therapies are not currently available for the prevention of the transition from simple steatosis to non-alcoholic steatohepatitis (NASH). We aimed to test if a Chinese herb-derived compound, emodin could halt the simple steatosis to NASH transition. LDLR^-/- mice were fed a western-type diet for 10 weeks; and during the last four weeks, the mice were intra-peritoneally injected daily with LPS with or without emodin. Systemic inflammation was evaluated by measurement of serum levels of cytokines and chemokines and flow cytometric analysis of spleen leukocytes. Liver inflammation was determined by histology, immunocytochemistry and flow cytometry. Quantitative real-time PCR and Western blot were performed to examine the effects of emodin on LPS-induced inflammatory responses in macrophages. Our data showed that emodin ameliorated systemic inflammation, reduced inflammatory cell infiltration in the liver, and attenuated liver function impairment. In vitro experiments showed emodin inhibited LPS-induced expression of proinflammatory cytokines in macrophages through suppressing Erk1/2 and p38 signaling. In conclusion, emodin inhibited the transition from simple steatosis to NASH in hyperlipidemic mice challenged with LPS through suppressing systemic and macrophage inflammation. Emodin may be developed as a therapy for NAFLD by the virtue of its anti-inflammatory effects.

Emodin Isolated from Polygoni cuspidati Radix Inhibits TNF-α and IL-6 Release by Blockading NF-κB and MAP Kinase Pathways in Mast Cells Stimulated with PMA Plus A23187

Emodin, a naturally occurring anthraquinone derivative isolated from Polygoni cuspidati radix, has several beneficial pharmacologic effects, which include anti-cancer, anti-diabetic, and anti-inflammatory activities. In this study, the authors examined the effect of emodin on the production of proinflammatory cytokines, such as, tumor necrosis factor (TNF)-α and interleukin (IL)-6, in mouse bone marrow-derived mast cells (BMMCs) stimulated with phorbol 12-myristate 13-acetate (PMA) plus the calcium ionophore A23187. To investigate the mechanism responsible for the regulation of pro-inflammatory cytokine production by emodin, the authors assessed its effects on the activations of transcriptional factor nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). Emodin attenuated the nuclear translocation of (NF)-κB p65 and its DNA-binding activity by reducing the phosphorylation and degradation of IκBα and the phosphorylation of IκB kinase B (IKK). Furthermore, emodin dose-dependently attenuated the phosphorylations of MAPKs, such as, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAP kinase, and the stress-activated protein kinases (SAPK)/c-Jun-N-terminal kinase (JNK). Taken together, the findings of this study suggest that the anti-inflammatory effects of emodin on PMA plus A23187-stimulated BMMCs are mediated via the inhibition of NF-κB activation and of the MAPK pathway.

EZH2 down-regulation exacerbates lipid accumulation and inflammation in in vitro and in vivo NAFLD

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent, chronic liver diseases, worldwide. It is a multifactorial disease caused by complex interactions between genetic, epigenetic and environmental factors. Recently, several microRNAs, some of which epigenetically regulated, have been found to be up- and/or down-regulated during NAFLD development. However, in NAFLD, the essential role of the Polycomb Group protein Enhancer of Zeste Homolog 2 (EZH2), which controls the epigenetic silencing of specific genes and/or microRNAs by trimethylating Lys27 on histone H3, still remains unknown. In this study, we demonstrate that the nuclear expression/activity of the EZH2 protein is down-regulated both in livers from NAFLD rats and in the free fatty acid-treated HepG2. The drop in EZH2 is inversely correlated with: (i) lipid accumulation; (ii) the expression of pro-inflammatory markers including TNF-α and TGF-β; and (iii) the expression of miR-200b and miR-155. Consistently, the pharmacological inhibition of EZH2 by 3-Deazaneplanocin A (DZNep) significantly reduces EZH2 expression/activity, while it increases lipid accumulation, inflammatory molecules and microRNAs. In conclusion, the results of this study suggest that the defective activity of EZH2 can enhance the NAFLD development by favouring steatosis and the de-repression of the inflammatory genes and that of specific microRNAs.

Activation of transsulfuration pathway by salvianolic acid a treatment: a homocysteine-lowering approach with beneficial effects on redox homeostasis in high-fat diet-induced hyperlipidemic rats

Background

Elevated homocysteine is a cardiovascular risk factor in hyperlipidemia. Transsulfuration pathway provides an endogenous pathway for homocysteine conversion to antioxidant glutathione (GSH). Salvianolic acid A (Sal A) contains two molecules of caffeic acid and one molecule of danshensu that is capable of enhancing homocysteine transsulfuration, which led to the hypothesis that Sal A has activatory effect on transsulfuration pathway and this effect may have beneficial effects on both homocysteine and redox status in hyperlipidemia.

Methods and results

To test this hypothesis, we developed a rat model of hyperlipidemia induced by high-fat diet for 16 weeks, during which rats were treated with 1 mg/kg salvianolic acid A (Sal A) for the final 4 weeks. Activities of key enzymes and metabolite profiling in the transsulfuration pathway revealed that hyperlipidemia led to elevated plasma homocysteine levels after 16-week dietary treatment, which was associated with reduced activities of homocysteine transsulfuration enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). The impaired transsulfuration pathway prevented homocysteine transsulfuration to cysteine, resulting in cysteine deficiency and subsequent reduction in GSH pool size. The redox status was altered in the setting of hyperlipidemia as indicated by GSH/GSSG ratio. Sal A treatment increased hepatic CBS and CSE activities, which was associated with reduced accumulation in circulating homocysteine levels and attenuated decline in hepatic cysteine content in hyperlipidemic rats. Sal A also led to an increase in GSH pool size, which subsequently caused a restored GSH/GSSG ratio. The activatory effect of Sal A on CBS was also observed in normal rats and in in vitro experiment.

Conclusion

Our results suggest that activation of transsulfuration pathway by Sal A is a promising homocysteine-lowering approach that has beneficial effects on redox homeostasis in hyperlipidemic settings.

Polyphenols from aerial parts of Polygonum bellardii and their biological activities

CONTEXT

Polygonum species have been used in the treatment of several types of inflammatory disorders and cancer. Nevertheless, there are no reports related to the anti-inflammatory and anti-proliferative activities of Polygonum bellardii All. (Polygonaceae).

OBJECTIVE

This study investigated the chemical composition of the methanol extract of P. bellardii. The anti-inflammatory and cytotoxic activities of methanol, n-butanol, ethyl acetate extracts and isolated polyphenols were determined.

MATERIALS AND METHODS

The chemical structure of the isolated compounds was elucidated using different spectral techniques. MTT assay was used to evaluate the anti-proliferative activity in HeLa, MCF-7 and HepG-2 cells. Inhibition of 5-lipoxygenase (5-LOX) activity and prostaglandin E2 (PGE2) production in stimulated HepG-2 cells were used to assess the anti-inflammatory activity.

RESULTS

The present study resulted in isolation of five compounds (new for the species). They were identified as gallic acid (1), quercetin (2), myricetin (3), quercetin-3-O-β-D-glucopyranoside (5) and myricetin-3-O-α-arabinofuranoside (7). Additionally, a couple of previously isolated compounds such as quercetin-3-O-(5″-acetyl-α-arabinofuranoside) (4) and myricetin-3-O-(5″-acetyl-α-arabinofuranoside) (6) were detected. The n-butanol extract has the highest cytotoxicity in HeLa, MCF-7 and HepG-2 cells, with IC₅₀ values of 15.26, 50.66 and 30.09 µg/ml, respectively. Compound 6 exhibited a marked cytotoxicity in HeLa (IC₅₀ 75.04 µg/ml) and HepG-2 (IC₅₀ 41.03 µg/ml) cells. Crude extracts and pure compounds inhibited the 5-LOX activity and PGE2 production in a dose-dependent manner (0.1-250 µg/ml).

DISCUSSION AND CONCLUSION

These results explain the traditional uses of P. bellardii and indicate that polyphenols, despite structural similarity, have different cytotoxic and anti-inflammatory effects.

Emodin regulating excision repair cross-complementation group 1 through fibroblast growth factor receptor 2 signaling

AIM: To investigate the molecular mechanisms underlying the reversal effect of emodin on platinum resistance in hepatocellular carcinoma.

METHODS: After the addition of 10 μmol/L emodin to HepG2/oxaliplatin (OXA) cells, the inhibition rate (IR), 50% inhibitory concentration (IC₅₀) and reversal index (IC₅₀ in experimental group/IC₅₀ in control group) were calculated. For HepG2, HepG2/OXA, HepG2/OXA/T, each cell line was divided into a control group, OXA group, OXA + fibroblast growth factor 7 (FGF7) group and OXA + emodin group, and the final concentrations of FGF7, emodin and OXA in each group were 5 ng/mL, 10 μg/mL and 10 μmol/L, respectively. Single-cell gel electrophoresis was conducted to detect DNA damage, and the fibroblast growth factor receptor 2 (FGFR2), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) and excision repair cross-complementing gene 1 (ERCC1) protein expression levels in each group were examined by Western blotting.

RESULTS: Compared with the IC₅₀ of 120.78 μmol/L in HepG2/OXA cells, the IC₅₀ decreased to 39.65 μmol/L after treatment with 10 μmol/L emodin; thus, the reversal index was 3.05. Compared with the control group, the tail length and Olive tail length in the OXA group, OXA + FGF7 group and OXA + emodin group were significantly increased, and the differences were statistically significant (P < 0.01). The tail length and Olive tail length were lower in the OXA + FGF7 group than in the OXA group, and this difference was also statistically significant. Compared with the OXA + FGF7 group, the tail extent, the Olive tail moment and the percentage of tail DNA were significantly increased in the OXA + emodin group, and these differences were statistically significant (P < 0.01). In comparison with its parental cell line HepG2, the HepG2/OXA cells demonstrated significantly increased FGFR2, p-ERK1/2 and ERCC1 expression levels, whereas the expression of all three molecules was significantly inhibited in HepG2/OXA/T cells, in which FGFR2 was silenced by FGFR2 shRNA. In the examined HepG2 cells, the FGFR2, p-ERK1/2 and ERCC1 expression levels demonstrated increasing trends in the OXA group and OXA + FGF7 group. Compared with the OXA group and OXA + FGF7 group, the FGFR2, p-ERK1/2, and ERCC1 expression levels were significantly lower in the OXA + emodin group, and these differences were statistically significant. In the HepG2/OXA/T cell line that was transfected with FGFR2 shRNA, the FGFR2, p-ERK1/2 and ERCC1 expression levels were significantly inhibited, but there were no significant differences in these expression levels among the OXA, OXA + FGF7 and OXA + emodin groups.

CONCLUSION: Emodin markedly reversed OXA resistance by enhancing OXA DNA damage in HepG2/OXA cells, and the molecular mechanism was related to the inhibitory effect on ERCC1 expression being mediated by the FGFR2/ERK1/2 signaling pathway.

Rapid and simple method for the determination of emodin in tartary buckwheat (Fagopyrum tataricum) by high-performance liquid chromatography coupled to a diode array detector

A simple and rapid method for determining emodin, an active factor presented in tartary buckwheat (Fagopyrum tataricum), by high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD) has been developed. Emodin was separated from an extract of buckwheat on a Kromasil-ODS C(18) (250 mm × 4.6 mm × 5 μm) column. The separation is achieved within 15 min on the ODS column. Emodin can be quantified using an external standard method detecting at 436 nm. Good linearity is obtained with a correlation coefficient exceeding 0.9992. The limit of detection and the limit of quantification are 5.7 and 19 μg/L, respectively. This method shows good reproducibility for the quantification of the emodin with a relative standard deviation value of 4.3%. Under optimized extraction conditions, the recovery of emodin was calculated as >90%. The validated method is successfully applied to quantify the emodin in tartary buckwheat and its products.