Protective effects of bergenin, the major constituent of Mallotus japonicus, on D-galactosamine-intoxicated rat hepatocytes

The traditional uses, phytochemistry, pharmacology and toxicology of Bergenia purparescens: A review comments and suggestions

Bergenia purpurascens (B. purpurascens, Saxifragaceae) has been used to treat several diseases in different countries, such as lung diseases, stomach problems, rheumatic pains, boosting immunity etc. However, the information on phytochemistry, pharmacology and toxicology of this plant has rarely been comprehensively and critically reported. This paper aims to study and evaluate its therapeutic potential, including the traditional uses and all the latest information of phytochemistry, pharmacology and toxicology. The main components of this plant are phenols compounds and the characteristic substance is bergenin.The results about modern pharmacology have shown that its pharmacological effects include antibacterial, antiviral, cough relieving, anti-inflammatory and so on. In addition, it could inhibit diabetic neuropathy, restore insulin secretion, treat cancer, protect liver and prevent Alzheimer's disease (AD). Thus, its therapeutic fields may be cancer, diabetic and AD in the future. The information will help to further update and study pharmacologic effect and action mechanism of this herb, which is more widely, effectively, and safely used in clinic.

Bergenin - a biologically active scaffold: Nanotechnological perspectives

Bergenin, 4-O-methyl gallic acid glucoside, is a bioactive compound present in various plants belonging to different families. The present work compiles scattered information on pharmacology, structure activity relationship and nanotechnological aspects of bergenin, collected from various electronic databases such as Sci Finder, PubMed, Google scholar, etc. Bergenin has been reported to exhibit hepatoprotective, anti-inflammatory, anticancer, neuroprotective, antiviral and antimicrobial activities. Molecular docking studies have shown that isocoumarin pharmacophore of bergenin is essential for its bioactivities. Bergenin holds a great potential to be used as lead molecule and also as a therapeutic agent for development of more efficacious and safer semisynthetic derivatives. Nanotechnological concepts can be employed to overcome poor bioavailability of bergenin. Finally, it is concluded that bergenin can be emerged as clinically potential medicine in modern therapeutics.

Bergenin impedes the generation of extracellular matrix in glomerular mesangial cells and ameliorates diabetic nephropathy in mice by inhibiting oxidative stress via the mTOR/β-TrcP/Nrf2 pathway

Bergenin, a plant polyphenol, has been reported to lower the blood glucose level and ameliorate kidney function in streptozotocin (STZ)-induced diabetic rats. Herein, its protective effect on diabetic nephropathy (DN) was explored in view of extracellular matrix (ECM) generation in glomerular mesangial cells. Glomerular mesangial cells were treated with high glucose, and Q-PCR as well as western blot were used to determine the expression of ECM. To establish the participation and role of mammalian target of rapamycin (mTOR) and nuclear factor erythroid-derived 2-related factor 2 (Nrf2) in ECM generation, a combination of l-leucine (activator of mTOR) and Nrf2 shRNA transfection were performed, respectively. Moreover, a DN model was established in mice using high-glucose/high-fat diet and STZ. Bergenin impeded the generation of TGF-β1 and ECM, decreased the levels of intracellular superoxide anion and hydrogen peroxide, and increased the activity of antioxidant enzymes in the glomerular mesangial cells (HBZY-1 and HRMC cells) treated with high glucose. The inhibition of ECM generation by bergenin was dependent on the down-regulation of oxidative stress as confirmed via a superoxide overexpression system. The activation of Nrf2 was required for bergenin to inhibit the oxidative stress and ECM generation. Moreover, bergenin was found to inhibit the phosphorylation of mTOR, which is located at the upstream of Nrf2. Bergenin did not interfere with the expression of Nrf2 mRNA and Keap1 (the classic degradation control factor of Nrf2), but markedly inhibited the protein expression of the β-TrcP, an effect which could be abolished by l-leucine. In DN model mice, l-leucine diminished the ability of bergenin to reduce the levels of superoxide anion, hydrogen peroxide and ECM, which contributed to the eradication of the ameliorative effect of bergenin on nephropathy. Bergenin can inhibit glucose-induced ECM production in glomerular mesangial cells through the down-regulation of oxidative stress via the mTOR/β-TrcP/Nrf2 pathway, and it might be a candidate drug for the prevention and treatment of DN.

Protective Effect of Bergenin against Cyclophosphamide-Induced Immunosuppression by Immunomodulatory Effect and Antioxidation in Balb/c Mice

In this study, the aim was to investigate the effect of bergenin on immune function and antioxidation in cyclophosphamide (Cy)-induced immunosuppressed mice. Firstly, we estimated its effect on immune organs. Histological analysis and indexes of immune organs showed that cyclophosphamide exhibited spleen and thymus injury compared with the normal control, which was alleviated by bergenin. Secondly, bergenin also enhanced the humoral immune function through increasing the level of IgM and IgG in serum. Thirdly, bergenin also enhanced the cellular immune function. The results indicate that bergenin increased peritoneal macrophage functions, the proliferation of T and B lymphocytes, NK and CTL cell activities, and T (CD4⁺ and CD8⁺) lymphocyte subsets. Besides, bergenin also had the ability to modulate the Th1/Th2 balance. Moreover, bergenin prevented the Cy-induced decrease in numbers of peripheral RBC, WBC and platelets, providing supportive evidence for their anti-leukopenia activities. Finally, bergenin also reversed the Cy-induced decrease in the total antioxidant capacity including activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). In conclusion, bergenin protected against Cy-induced adverse reactions by enhancing humoral and cellular immune functions and augmenting antioxidative activity and could be considered as a potential immunomodulatory agent.

Comparative pharmacokinetics of bergenin, a main active constituent of Saxifraga stolonifera Curt., in normal and hepatic injury rats after oral administration

Bergenin, isolated from the herb of Saxifrage stolonifera Curt. (Hu-Er-Cao) has hepatoprotective, anti-inflammatory, antitussive, and neuroprotective activities. The aim of the present study was to establish a simple, rapid, and sensitive RP-HPLC method for determination of bergenin in rat plasma and compare its oral pharmacokinetic behaviors in normal and CCl₄-induced hepatic injury rats. With norisoboldine as an internal standard, chromatographic separation was performed on a C₁₈ analytical column with acetonitrile and water (11 : 89, V/V) containing 0.1% formic acid as the mobile phase. A good linearity was obtained over the range of 100-10 000 ng·mL^-1. The lower limit of quantification was 50 ng·mL^-1. The developed method was successfully applied to a study of the pharmacokinetic difference of bergenin (100 mg·kg^-1) between normal and hepatic injury rats after oral administration. Marked alterations of pharmacokinetic parameters in hepatic injury rats were observed. Compared to normal rats, the AUC_(0-∞) of bergenin in hepatic injury rats was elevated to 2.11-fold and C_max was increased by 130%, whereas CL value was only 55% of the normal rats, suggesting that the systemic exposure of bergenin was significantly increased under hepatic injury status.

Bergenin Content and Free Radical Scavenging Activity of Bergenia Extracts

Our research was focused on the evaluation of bergenin content and free radical scavenging activity of extracts prepared from three different species of Bergenia - B. crassifolia (L.) Fritsch., B. ciliata (Haw.) Sternb. and B. x ornata Stein. collected during different seasons. Using an HPLC method, the highest total amount of bergenin was revealed in the leaves of B. x ornata and B. crassifolia (4.9 - 5.1 mg.g−1). Free radical scavenging power was determined by two methods - FRAP and NADH. The best free radical scavengers were B. crassifolia (FRAP: 6.7 - 15.9 mg GAE.100g−1; NADH: 20.3 - 50.9%) and B. ornata (FRAP: 13.7 - 15.2 mg GAE.100g−1; NADH: 29.3 - 31.1%). The lowest content of bergenin and the weakest radical scavenger was B. ciliata (bergenin: 3.1 mg.g−1; FRAP: 5.5 - 11.0 mg GAE.100g−1; NADH: 23.2 - 25.6%). The presence of a large percentage of bergenin is responsible for the radical scavenging activity, as shown by the results from the FRAP and NADH assays. Significant, positive correlation was found between bergenin content and radical scavenging activity in both methods.

Diversity, pharmacology and synthesis of bergenin and its derivatives: potential materials for therapeutic usages

Bergenin, a natural secondary metabolite, has been isolated from different parts of a number of plants. It is one of active ingredients in herbal and Ayurvedic formulations. It exhibits antiviral, antifungal, antitussive, antiplasmodial, antiinflammatory, antihepatotoxic, antiarrhythmic, antitumor, antiulcerogenic, antidiabetic and wound healing properties. It has been analyzed and estimated in different plant extracts, blood and drug samples using chromatographic techniques, and pharmacokinetic studies have been made. Several bergenin derivatives were isolated and/or synthesized and were found to possess pharmacological activities. Total synthesis of bergenin and its derivatives were reported. This review article covers literature on bergenin and its derivatives until 2013. Ethnomedicinal value of bergenin containing plant materials is also highlighted. This comprehensive review provides information on the potentiality of bergenin and its derivatives for therapeutic usages.

ent-Labdane diterpenes from the stems of Mallotus japonicus

Eight new ent-labdane diterpenoids, mallonicusins A-H (1-8), were isolated from the stems of Mallotus japonicus. Their structures, including the absolute configurations, were determined by extensive analyses of spectroscopic data and the ECD spectra of the Pr(FOD)₃ complex of substrates in CCl₄. The absolute configuration of compound 1 was confirmed by single-crystal X-ray crystallography using Cu Kα radiation.

Antioxidant and anti-α-glucosidase compounds from the rhizome of Peltiphyllum peltatum (Torr.) Engl

The antioxidant, anti-α-glucosidase and anticholinesterase effects of the alcohol extract of fresh underground rhizomes of Peltiphyllum peltatum were studied. A potent antioxidant activity accompanied by a selective α-glucosidase effect was observed for the crude extract. Further activity-guided fractionation (petroleum ether, chloroform, ethyl acetate, n-butanol and water) resulted in the identification of the ethyl acetate fraction with the highest antioxidant effect. Gallic acid, methyl-3-O-methyl gallate, catechin, gallocatechin, bergenin and 11-O-galloylbergenin were isolated from the ethyl acetate fraction. While all the isolated compounds did show a variable degree of radical scavenging effect, 11-O-galloylbergenin was identified as the selective α-glucosidase inhibitor. The isolation, structural elucidation and biological effects of these compounds are discussed.

Phytochemical, antioxidant and anti-α-glucosidase activity evaluations of Bergenia cordifolia

The antioxidant, anti-α-glucosidase and anticholinesterase activity of the leaves and rhizomatous extract of Bergenia cordifolia were investigated. The rhizomes extract that showed a higher degree of 1,1-diphenyl-2-picrylhydrazyl radical scavenging and anti-α-glucosidase activity than reference compounds (rutin and acarbose respectively) were subjected to phytochemical analysis. The study revealed that previously unknown minor constituents from the plant, (+)-catechin 3-O-gallate, (+)-catechin 3,5-di-O-gallate and 1,2,4,6-tetra-O-galloyl-β-D-glucopyranoside, were the radical scavenging and anti-α-glucosidase principles. These compounds as well as the crude extracts were weak acetylcholienesterase inhibitors, suggesting a higher degree of selectivity against α-glucosidase enzyme. In comparison with the minor constituents, the previously known major constituents of the plant, bergenin and arbutin, were poor radical scavengers and enzyme inhibitors.

Analgesic and anti-inflammatory activities of 11-O-galloylbergenin

AIMS OF THE STUDY

Current study was designed to explore the analgesic and anti-inflammatory effects of a constituent isolated from Mallotus philippinensis, in order to validate its folk use.

MATERIALS AND METHODS

11-O-galloylbergenin was isolated from ethanolic extract of Mallotus philippinensis. Analgesic and anti-inflammatory activities of the test compound were assessed using formalin test and carrageenan-induced paw edema models.

RESULTS

11-O-galloylbergenin showed significant analgesic activity at doses of 20 and 40 mg/kg against formalin test in rats. Similarly, 11-O-galloylbergenin exhibited significant anti-inflammatory activity in carrageenan-induced paw edema model at doses of 10, 20 and 30 mg/kg.

CONCLUSION

11-O-galloylbergenin has demonstrated its significant potential to be further investigated for its discovery as a new lead compound for management of pain and inflammation.

Determination and pharmacokinetic study of bergenin in rat plasma by RP-HPLC method

A validated reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the determination of bergenin in rat plasma. Bergenin in rat plasma was extracted with methanol, which also acted as a deproteinization agent. Chromatographic separation of bergenin was performed on a C(18) column, with a mobile phase of methanol-water (22:78, v/v) at a flow-rate of 0.8 mL/min and an operating temperature of 40 degrees C, and UV detection was set at 220 nm. The calibration curve was linear over the range 0.25-50 microg/mL (r = 0.9990) in rat plasma. The limit of quantification was 0.25 microg/mL using a plasma sample of 100 microL. The extraction recoveries were 83.40 +/- 6.02, 81.49 +/- 2.40 and 72.51 +/- 2.64% at concentrations of 0.5, 5 and 50 microg/mL, respectively. The intra-day and inter-day precision and accuracy were validated by relative standard deviation (RSD%) and relative error (RE%), which were in the ranges 3.74-9.91 and -1.6-8.0%. After intravenous administration to rats at the dose of 11.25 mg/kg, the plasma concentration-time curve of bergenin was best conformed to a two-compartment open model. The main pharmacokinetic parameters indicated that bergenin exhibited a wide distribution and moderate elimination velocity in rat.

Protective effects of acetylbergenin against carbon tetrachloride-induced hepatotoxicity in rats

The present study was undertaken to investigate whether or not the hepatoprotective activity of acetylbergenin was superior to bergenin in carbon tetrachloride (CCl4)-intoxicated rat. Acetylbergenin was synthesized by acetylating bergenin, which was isolated from Mallotus japonicus. The hepatoprotective effects of acetylbergenin were examined against CCl4-induced liver damage in rats by means of serum and liver biochemical indices. Acetylbergenin was administered orally once daily for 7 successive days, then a 0.5 ml/kg mixture of CCl4 in olive oil (1:1) was intraperitoneally injected at 12 h and 36 h after the final administration of acetylbergenin. Pretreatment with acetylbergenin reduced the elevated serum enzymatic activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and gamma-glutamyltransferase in a dose dependent fashion. Acetylbergenin also prevented the elevation of hepatic malondialdehyde formation and depletion of glutathione content dose dependently in CCl4-intoxicated rats. In addition, the decreased activities of glutathione S-transferase and glutathione reductase were restored to almost normal levels. The results of this study strongly suggest that acetylbergenin has potent hepatoprotective activity against CCl4-induced hepatic damage in rats by glutathione-mediated detoxification as well as having free radical scavenging activity. In addition, acetylbergenin doses of 50 mg/kg showed almost the same levels of hepatoprotective activity as 100 mg/kg of bergenin, indicating that lipophilic acetylbergenin is more active against the antihepatotoxic effects of CCl4 than those of the much less lipophilic bergenin.

Effects of acetylbergenin against D -galactosamine-induced hepatotoxicity in rats

The hepatoprotective effects of acetylbergenin were examined against D -galactosamine (GalN)-induced liver damage in rats, compared with that of bergenin reported previously. Acetylbergenin was synthesized from acetylation of bergenin, isolated from Mallotus japonicus, to increase lipophilic and physiological activities. Acetylbergenin was administered orally once daily for 7 days and then GalN (400 mg kg(-1), i.p.) was injected at 24 h and 96 h after the final administration of acetylbergenin. Acetylbergenin reduced the elevated serum enzyme activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and gamma -glutamyltransferase and the formation of hepatic malondialdehyde induced by GalN. Acetylbergenin also significantly restored towards normalization the decreased levels of glutathione and the decreased activities of glutathione S-transferase and glutathione reductase induced by GalN. Therefore, these results suggest that acetylbergenin has hepatoprotective effects against GalN-induced hepatotoxicity by inhibiting lipid peroxidation and maintaining an adequate level of GSH for the detoxification of xenobiotics as underlying hepatoprotective mechanisms. In addition, lipophilic acetylbergenin showed more activity in the hepatoprotection than that of the much less lipophilic bergenin reported previously.

Hepatoprotective effects of bergenin, a major constituent of Mallotus japonicus, on carbon tetrachloride-intoxicated rats

The hepatoprotective effects of bergenin, a major constituent of Mallotus japonicus, were evaluated against carbon tetrachloride (CCl(4))-induced liver damage in rats. Bergenin at a dose of 50, 100 or 200 mg/kg was administered orally once daily for successive 7 days and then a mixture of 0.5 ml/kg (ip) of CCl(4) in olive oil (1:1) was injected two times each at 12 and 36 h after the final administration of bergenin. The substantially elevated serum enzymatic activities of alanine/aspartate aminotransferase, sorbitol dehydrogenase and gamma-glutamyltransferase due to CCl(4) treatment were dose dependently restored towards normalization. Meanwhile, the decreased activities of glutathione S-transferase and glutathione reductase were restored towards normalization. In addition, bergenin also significantly prevented the elevation of hepatic malondialdehyde formation and depletion of reduced glutathione content in the liver of CCl(4)-intoxicated rats in a dose dependent fashion. The results of this study clearly indicate that bergenin has a potent hepatoprotective action against CCl(4)-induced hepatic damage in rats.