Antcin C from Antrodia cinnamomea Protects Liver Cells Against Free Radical-Induced Oxidative Stress and Apoptosis In Vitro and In Vivo through Nrf2-Dependent Mechanism

Protective effect of bioactive components from Rubi fructus against oxidative damage in human ovarian granulosa cells induced by 2,2-azobis (2-methylpropionamidine) dihydrochloride

BACKGROUND

Diminished ovarian reserve has a serious impact on female reproduction with an increasing incidence every year. An important cause of this is oxidative stress. Rubi fructus, a traditional medicinal and edible plant, has shown therapeutic effects against gynecological diseases. Vanillic acid, isoquercitrin, kaempferol-3-O-rutinoside, kaempferol-3-O-sophoroside, oleanolic acid, tormentic acid, tiliroside, and ellagic acid are the major bioactive components in R. fructus. However, studies involved in the effectiveness and mechanism of these components in oxidative stress-induced ovarian dysfunction are scarce.

RESULTS

In this study, the protective mechanisms of the bioactive components were evaluated in human ovarian granulosa cells. Isoquercitrin was significantly superior to other bioactive components in relieving damage in human ovarian granulosa cells induced by 2,2-azobis (2-methylpropionamidine) dihydrochloride, considering enhanced cell viability, reduced reactive oxygen species accumulation, and improved mitochondrial membrane potential level. Isoquercitrin protected human ovarian granulosa cells from oxidative stress by regulating the enzyme activity of glutathione peroxidase, inhibiting cell apoptosis, improving the expression of genes related to oxidative stress, and ameliorating heme oxygenase 1 protein expression.

CONCLUSION

Isoquercitrin, a bioactive component in R. fructus, has a significant protective effect on oxidative damage induced by 2,2-azobis (2-methylpropionamidine) dihydrochloride in human ovarian granulosa cells, providing evidence for its potential application in protecting ovarian function. © 2024 Society of Chemical Industry.

Aerobic Exercise Ameliorates Liver Injury in Db/Db Mice by Attenuating Oxidative Stress, Apoptosis and Inflammation Through the Nrf2 and JAK2/STAT3 Signalling Pathways

Objective

Diabetes mellitus (DM) implicates oxidative stress, apoptosis, and inflammation, all of which may contribute liver injury. Aerobic exercise is assured to positively regulate metabolism in the liver. This project was designed to investigate whether and how aerobic exercise improves DM-induced liver injury.

Methods

Seven-week-old male db/db mice and age-matched m/m mice were randomly divided into a rest control group or a group that received 12 weeks of aerobic exercise by treadmill training (10 m/min). Haematoxylin and eosin (HE) staining, electron microscopy, Oil Red O staining and TUNEL assays were used to evaluate the histopathological changes in mouse liver. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TRIG), cholesterol (CHOL) were analyzed by serum biochemical analysis. Interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and tissue levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were analyzed via ELISA. Nuclear factor E2-associated factor-2 (Nrf2), nuclear factor κB (NF-κB) and JAK2/STAT3 pathway-related proteins were measured by immunofluorescence, Western blotting and q-PCR. F4/80 expression in liver tissues was assessed by immunohistochemistry.

Results

In diabetic mice, exercise training significantly decreased the levels of serum TRIG, CHOL, IL-6, TNF-α, ALT and AST; prevented weight gain, hyperglycaemia, and impaired glucose and insulin tolerance. Morphologically, exercise mitigated the diabetes-induced increase in liver tissue microvesicles, inflammatory cells, F4/80 (macrophage marker) levels, and TUNEL-positive cells. In addition, exercise reduced the apoptosis index, which is consistent with the results for caspase-3 and Bax. Additionally, exercise significantly increased SOD activity, decreased MDA levels, activated Nrf2 and decreased the expression of NF-kB, phosphorylated JAK2 and STAT3 proteins in the livers of diabetic mice.

Conclusion

This study demonstrated that aerobic exercise reversed liver dysfunction in db/db mice with T2DM by reducing oxidative stress, apoptosis and inflammation, possibly by enhancing Nrf2 expression and inhibiting the JAK2/STAT3 cascade response.

Structural basis of Nrf2 activation by flavonolignans from silymarin

Several properties of silymarin (SM) extract have been attributed to their three major flavonolignans (silybin, silychristin, and silydianin) and their 2,3-dehydro derivatives (2,3-dehydrosilybin, 2,3-dehydrosilychristin, and 2,3-dehydrosilydianin). Experimental findings have suggested that the antioxidative and protective activities of these compounds could be due to their ability to activate nuclear factor erythroid 2-related factor 2 (Nrf2). The mechanism by which SM compounds exert their effect has been suggested to be by disrupting the complex between Nrf2 and Kelch-like ECH-associated protein 1 (Keap1). However, information about the structural and energetic basis of the inhibitory mechanism of SM compounds on the Nrf2-Keap1 pathway is lacking. We evaluated the binding properties of SM compounds because experimental findings have pointed to them as potential activators of Nrf2. Our study combined docking and molecular dynamics (MD) simulations with the Poisson-Boltzmann and generalized Born and surface area (MMPBSA and MMGBSA) methods and quantum mechanics-molecular mechanics (QMMM) calculations to investigate Keap1-ligand interactions. Our results predicted that silybin_A and 2,3-dehydrosilybin bind to Keap1, forming interactions with the same pockets as those observed for the cocrystallized Keap1-Cpd16 complex but with more favorable binding free energies. These findings indicate that both natural compounds are potential activators of Nrf2.

Chemical Composition and Chronic Toxicity of Disc-Cultured Antrodia cinnamomea Fruiting Bodies

Antrodia cinnamomea (AC) is a popular fungus for use as folk medicine in health maintenance and disease prevention and treatment. Disc culture is a novel technique for producing AC fruiting bodies. This study aimed to investigate the bioactive components and toxicological properties of disc-cultured AC fruiting body powders (ACP) in rats. The HPLC technique was used to quantify the composition of bioactive triterpenoids in ACP. Toxicological properties were evaluated on male and female Sprague-Dawley rats receiving ACP orally at 200, 600, and 1000 mg/kg body weight for 90 days; the control group received only distilled water. The results show that ACP contained seven important AC index compounds, namely antcins A, B, C, K, and H, dehydrosulphurenic acid, and dehydroeburicoic acid. At the tested doses, oral ACP administration for 90 days caused no mortality, adverse effects on general health, body and organ weights, and food intake. Furthermore, no significant variations were observed in hematological and biochemical parameters among either sex of ACP-treated and control animals. An histopathological examination of vital organs showed no significant structural changes in organs, even in high-dose ACP-treated animals. This study indicated that ACP contained the major bioactive triterpenoids of AC fruiting bodies, and its no-observed-adverse-effect level (NOAEL) was 1000 mg/kg/day, about 20 times the recommended daily intake.

Review of Bioactivity, Isolation, and Identification of Active Compounds from Antrodia cinnamomea

Antrodia cinnamomea is a precious and popular edible and medicinal mushroom. It has attracted increasing attention due to its various and excellent bioactivities, such as hepatoprotection, hypoglycemic, antioxidant, antitumor, anticancer, anti-inflammatory, immunomodulation, and gut microbiota regulation properties. To elucidate its bioactivities and develop novel functional foods or medicines, numerous studies have focused on the isolation and identification of the bioactive compounds of A. cinnamomea. In this review, the recent advances in bioactivity, isolation, purification, and identification methods of active compounds from A. cinnamomea were summarized. The present work is beneficial to the further isolation and discovery of new active compounds from A. cinnamomea.

Honokiol Protects the Kidney from Renal Ischemia and Reperfusion Injury by Upregulating the Glutathione Biosynthetic Enzymes

Glutathione (GSH) is an endogenous antioxidant found in plants, animals, fungi, and some microorganisms that protects cells by neutralizing hydrogen peroxide. Honokiol, an active ingredient of Magnolia officinalis, is known for antioxidant, anti-inflammatory, and anti-bacterial properties. We investigated the protective mechanism of honokiol through regulating cellular GSH in renal proximal tubules against acute kidney injury (AKI). First, we measured cellular GSH levels and correlated them with the expression of GSH biosynthetic enzymes after honokiol treatment in human kidney-2 (HK-2) cells. Second, we used pharmacological inhibitors or siRNA-mediated gene silencing approach to determine the signaling pathway induced by honokiol. Third, the protective effect of honokiol via de novo GSH biosynthesis was investigated in renal ischemia-reperfusion (IR) mice. Honokiol significantly increased cellular GSH levels by upregulating the subunits of glutamate-cysteine ligase (Gcl)—Gclc and Gclm. These increases were mediated by activation of nuclear factor erythroid 2-related factor 2, via PI3K/Akt and protein kinase C signaling. Consistently, honokiol treatment reduced the plasma creatinine, tubular cell death, neutrophil infiltration and lipid peroxidation in IR mice and the effect was correlated with upregulation of Gclc and Gclm. Conclusively, honokiol may benefit to patients with AKI by increasing antioxidant GSH via transcriptional activation of the biosynthetic enzymes.

Terpenoids from the medicinal mushroom Antrodia camphorata: chemistry and medicinal potential

Covering: up to February 2020Antrodia camphorata is a medicinal mushroom endemic to Taiwan for the treatment of intoxication, liver injury, cancer, and inflammation. Owing to its rare occurrence and potent pharmacological activities, efforts have been devoted to identify its bioactive constituents, especially terpenoids. Since 1995, a total of 162 terpenoids including triterpenoids, meroterpenoids, sesquiterpenoids, diterpenoids, and steroids have been characterized. The ergostane-type triterpenoids (antcins) and meroterpenoids (antroquinonols) are characteristic constituents of A. camphorata. The terpenoids show anti-cancer, hepatoprotective, anti-inflammatory, anti-diabetic, and neuroprotective activities. This review summarizes the research progress on terpenoids in A. camphorata during 1995-2020, including structural diversity, resources, biosynthesis, pharmacological activities, metabolism, and toxicity. The medicinal potential of the terpenoids is also discussed.

A Pilot Study to Assess Food Safety and Potential Cholesterol-Lowering Efficacy of Antrodia cinnamomea Solid-State Cultivated Mycelium in Healthy Adults

Antrodia cinnamomea is a Taiwanese medicinal mushroom with multiple pharmacological activities. Antrodia cinnamomea solid-state cultivated mycelium (LAC) exerts health-related effects in animal and cell models, but clinical data is limited. This study aimed to determine the safety and effects of LAC on human physiological functions. In an open-label, single-arm study, 32 healthy men and women ingested LAC capsules for three months. The subjects were monitored during the study and one month after the study end-point. LAC consumption did not significantly change fasting blood glucose, blood pressure, and triglyceride levels or liver and renal function indices. No adverse events occurred during the trial. Moreover, a significant change from baseline in total cholesterol levels was observed; men and women had decreases of 5.7% and 5.3%, respectively. Based on these, the ingestion of LAC-capsule has a considerable degree of safety and has the potential to reduce total cholesterol in healthy adults.

Combination of cut-log cultivated fruiting body and solid-state cultured mycelia of Taiwanofungus camphoratus ameliorates CCl4-induced liver injury in rats

Taiwanofungus camphoratus, a medicinal mushroom indigenous to Taiwan, possesses various pharmacological functions. The most recognized ethnopharmacological relevance of T. camphoratus is hepatoprotection since it was traditionally used for treating liver disorders by Taiwan aborigines. The aim of this study is to evaluate the hepatoprotective effect of the combination of fruiting body and solid-state cultured mycelia of T. camphoratus (LDAC) on carbon tetrachloride (CCl₄)-induced chronic liver damage in rats. We treated Wistar rats daily with low, medium and high [87.5, 175 and 437.5 mg/kg body weight (bw), respectively] doses of LDAC for 9 weeks. After the first week of treatment, rats were administered 20% CCl₄ (0.5 mL/0.3 kg bw) twice a week to induce liver damage until the treatment ended. The results showed that administration of LDAC by oral gavage significantly reduced the absolute weight of the liver and the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in CCl₄-treated rats_. The activities of the antioxidant enzymes glutathione peroxidase (GPx), glutathione reductase (GRd) and catalase (CAT) were increased by LDAC treatment. Moreover, LDAC improved CCl₄-induced hepatic vacuolization, necrosis and fibrosis in a dose-dependent manner, and no adverse effects were observed in the LDAC-treated groups. Based on the results, LDAC is a promising hepatoprotective agent for preventing and ameliorating CCl₄-induced chronic liver injury, and this effect might be exerted through activation of the antioxidant defense system.

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Combining cut-log fruiting body and solid-state mycelia of T. camphoratus is an efficient production.

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The HPLC fingerprint shows the index compounds in the combination (LDAC).

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LDAC decreases serum ALT and AST levels and elevates antioxidant activity in CCl₄-treated rats.

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LDAC dramatically improves rat hepatic necrosis and fibrosis induced by CCl₄.

Vitexin protects against ethanol-induced liver injury through Sirt1/p53 signaling pathway

In the present study, we aimed to investigate the therapeutic effect of Vitexin on inhibiting ethanol-induced liver damage and explore the underling mechanism. In vitro, the injury was induced in LO2 cell by 100 mM ethanol. Cell viability, AST, oxidative stress, inflammation, apoptosis rate, and related gene and protein expressions were assessed. Alcoholic liver injury model was made by intragastric infusion of alcohol for 4 weeks on male KM mice. Liver index, AST, ALT, TC, TG, TP, TBIL in serum and liver pathology were evaluated. Meanwhile, the level of SOD, MDA and TNF-α also were detected by Kits. Quantitative RT-PCR and Western blotting analysis the Sirt1/p53 pathway related gene and protein expressions. In vitro, Vitexin restored cytoactive and inhibited the releasing of AST induced by ethanol in LO2 cell. Vitexin treatment significantly suppressed the elevation of aminotransferase, blood lipid, UA in mice. Vitexin ameliorated liver pathological changes induced by ethanol. Vitexin supplement restored the decrease of Sirt1/Bcl-2 expression, restrained the elevation of caspase3, cleaved caspse-3, p53 and ac-p53 expression in vivo and in vitro. Vitexin has a protective effect against ethanol-induced liver damage, and the underlying mechanism is probably through Sirt1/p53 mediated mitochondrial apoptotic pathway.

Silibinin attenuates adipose tissue inflammation and reverses obesity and its complications in diet-induced obesity model in mice

Background

Obesity is a multifactorial chronic disease that comprises several pathological events, such as adipose hypertrophy, fatty liver and insulin resistance. Inflammation is a key contributer to development of these events, and therefore, targeting inflammation is increasingly considered for management of obesity and its complications. The aim of the current study was to investigate therapeutic outcomes of anti-inflammatory activities of the natural compound Silibinin in reversing obesity and its complication in mice.

Methods

C57BL/6 male mice were fed high-fat diet for 8 weeks until development of obesity, and then injected with 50 mg/kg silibinin intraperitoneally twice per week, or vehicle for 8 weeks. Throughout the experiment, mice were continuously checked for body weight and food intake, and glucose tolerance test was performed toward the end of the experiment. Animals were sacrificed and serum and tissues were collected for biochemical, histological, and gene expression analysis to assess silibinin effects on adipose inflammation, fat accumulation, liver adipogenesis and glucose homeostasis.

Results

Silibinin treatment reversed adipose tissue inflammation and adipocyte hypertrophy, and blocked progression in weight gain and obesity development with no significant effects on rates of food intake. Silibinin also reversed fatty liver disease and restored glucose homeostasis in treated animals, and reversed hyperglycemia, hyperinsulinemia and hypertriglyceridemia.

Conclusion

In this study, we demonstrated that silibinin as an anti-inflammatory therapy is a potential alternative to manage obesity, as well as its related complications. Moreover, silibinin-based therapies could further evolve as a novel treatment to manage various inflammation-driven disorders.

Treatment of hepatotoxicity induced by γ-radiation using platelet-rich plasma and/or low molecular weight chitosan in experimental rats

Background and aim: Platelet-rich plasma (PRP) is rich in growth factors and plays an important role in tissue healing and cytoprotection. Also, it has been proved that low molecular weight chitosan (LMC) possesses many outstanding health benefits. The aim of this study was to assess the possibility of using PRP and/or fungal LMC to treat hepatotoxicity induced by γ-radiation in albino rats.Materials and methods: Forty-eight adult male albino rats were randomly divided into eight groups. Group I (control), Group II (PRP alone), Group III (LMC alone), Group IV (PRP + LMC), Group V (γ-irradiated alone), Group VI (γ-irradiated + PRP), Group VII (γ-irradiated + LMC), and Group VIII (γ-irradiated + PRP + LMC). The irradiated rats were whole body exposed to γ-radiation (8 Gy) as fractionated doses (2 Gy) twice a week for 2 consecutive weeks. The treated groups received PRP (0.5 mL/kg body weight, s.c.) and/or LMC (10 mg/kg body weight, s.c.) 2 days a week 1 h after every dose of γ-radiation and continued for another week after the last dose of radiation. Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities, as well as reduced glutathione (GSH) content, malondialdehyde (MDA), total antioxidant capacity (TAC), and nuclear factor erythroid 2-related factor 2 (Nrf2) levels in the liver tissue and relative expression of microRNA-21 (miR-21) in serum were measured, in addition to histopathological examination.Results: Exposure of rats to γ-radiation resulted in a significant increase in serum ALT and AST activities, hepatic MDA levels, and serum miR-21 relative expression, along with a significant decrease in hepatic GSH content, TAC, and Nrf2 levels. Treatment with PRP and/or fungal LMC after exposure to γ-radiation ameliorated these parameters and improved the histopathological changes induced by γ-radiation.Conclusions: The results demonstrated that PRP and/or LMC inhibited γ-radiation-induced hepatotoxicity and using both of them together seems more effective. They can be a candidate to be studied toward the development of a therapeutic strategy for liver diseases.

Diversity of potentially exploitable pharmacological activities of the highly prized edible medicinal fungus Antrodia camphorata

Antrodia camphorata, also known as A. cinnamomea, is a precious medicinal basidiomycete fungus endemic to Taiwan. This article summarizes the recent advances in research on the multifarious pharmacological effects of A. camphorata. The mushroom exhibits anticancer activity toward a large variety of cancers including breast, cervical, ovarian, prostate, bladder, colorectal, pancreatic, liver, and lung cancers; melanoma; leukemia; lymphoma; neuroblastoma; and glioblastoma. Other activities encompass antiinflammatory, antiatopic dermatitis, anticachexia, immunoregulatory, antiobesity, antidiabetic, antihyperlipidemic, antiatherosclerotic, antihypertensive, antiplatelet, antioxidative, antiphotodamaging, hepatoprotective, renoprotective, neuroprotective, testis protecting, antiasthmatic, osteogenic, osteoprotective, antiviral, antibacterial, and wound healing activities. This review aims to provide a reference for further development and utilization of this highly prized mushroom.

Antrodia cinnamomea Enhances Chemo-Sensitivity of 5-FU and Suppresses Colon Tumorigenesis and Cancer Stemness via Up-Regulation of Tumor Suppressor miR-142-3p

5-Fluorouracil (5-FU) regimen remains the backbone of the first-line agent to treat colon cancer, but often these patients develop resistance. Cancer stem cells (CSC's) are considered as one of the key contributors in the development of drug resistance and tumor recurrence. We aimed to provide preclinical evidence for Antrodia cinnamomea (AC), as a potential in suppressing colon cancer CSC's to overcome 5-FU drug-resistant. In-vitro assays including cell viability, colony formation, AC + 5-FU drug combination index and tumor sphere generation were applied to determine the inhibitory effect of AC. Mouse xenograft models also incorporated to evaluate in vivo effect of AC. AC treatment significantly inhibited the proliferation, colony formation and tumor sphere generation. AC also inhibited the expression of oncogenic markers (NF-κB, and C-myc), EMT/metastasis markers (vimentin and MMP3) and stemness associated markers (β-catenin, SOX-2 and Nanog). Sequential treatment of AC and 5-FU synergized and reduces colon cancer viability both in vivo and in vitro. Mechanistically, AC mediated anti-tumor effect was associated with an increased level of tumor suppressor microRNAs especially, miR142-3p. AC can be a potent synergistic adjuvant, down-regulates cancer stemness genes and enhances the antitumor ability of 5-FU by stimulating apoptosis-associated genes, suppressing inflammation and metastasis genes through miR142-3p in colon cancer.

Anti-EMT properties of CoQ0 attributed to PI3K/AKT/NFKB/MMP-9 signaling pathway through ROS-mediated apoptosis

Background

Breast cancer is the most prevalent cancer among women. In triple-negative breast cancer (TNBC) cells, a novel quinone derivative, coenzyme Q₀ (CoQ₀), promotes apoptosis and cell-cycle arrest. This study explored the anti-epithelial–mesenchymal transition (EMT) and antimetastatic attributes of CoQ₀ in TNBC (MDA-MB-231).

Methods

Invasion, as well as MTT assays were conducted. Lipofectamine RNAiMAX was used to transfect cells with β-catenin siRNA. Through Western blotting and RT-PCR, the major signaling pathways’ protein expressions were examined, and the biopsied tumor tissues underwent immunohistochemical and hematoxylin and eosin staining as well as Western blotting.

Results

CoQ₀ (0.5–2 μM) hindered tumor migration, invasion, and progression. Additionally, it caused MMP-2/− 9, uPA, uPAR, and VEGF downregulation. Furthermore, in highly metastatic MDA-MB-231 cells, TIMP-1/2 expression was subsequently upregulated and MMP-9 expression was downregulated. In addition, CoQ₀ inhibited metastasis and EMT in TGF-β/TNF-α-stimulated non-tumorigenic MCF-10A cells. Bioluminescence imaging of MDA-MB-231 luciferase–injected live mice demonstrated that CoQ₀ significantly inhibited metastasis of the breast cancer to the lungs and inhibited the development of tumors in MDA-MB-231 xenografted nude mice. Silencing of β-catenin with siRNA stimulated CoQ₀-inhibited EMT. Western blotting as well as histological analysis established that CoQ0 reduced xenografted tumor development because apoptosis induction, cell-cycle inhibition, E-cadherin upregulation, β-catenin downregulation, and metastasis and EMT regulatory protein modulation were observed.

Conclusions

CoQ₀ inhibited the progression of metastasis as well as EMT (in vitro and in vivo). The described approach has potential in treating human breast cancer metastasis.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1196-x) contains supplementary material, which is available to authorized users.

Antcins, triterpenoids from Antrodia cinnamomea, as new agonists for peroxisome proliferator-activated receptor α

Peroxisome proliferator-activated receptor α (PPARα) is a nuclear hormone receptor that transcriptionally regulates lipid metabolism and inflammation; therefore, PPARα agonists are promising agents to treat dyslipidemia and metabolic disorders. PPARα full agonists, such as fibrates, are effective anti-hypertriglyceride agents, but their use is limited by adverse side effects. Hence, the aim of this study was to identify small molecules that can activate PPARα while minimizing the adverse effects. Antrodia cinnamomea, a rare medical mushroom, has been used widely in Asian countries for the treatment of various diseases, including liver diseases. Antcin B, H and K (antcins) and ergostatrien-3β-ol (EK100) are bioactive compounds isolated from A. cinnamomea with anti-inflammatory actions. Antcins, ergostane-type triterpenoids, contain the polar head with carboxylate group and the sterol-based body. Here, we showed at the first time that sterol-based compounds, antcins, but not EK100, activate PPARα in a cell-based transactivation study. The in silico docking studies presented several significant molecular interactions of antcins, including Tyr314, and His440 in the ligand-binding domain of PPARα, and these interactions are required for helix 12 (H12) stabilization. We propose that PPARα activation activity of antcins is related to their binding mode which requires conventional H12 stabilization, and that antcins can be developed as safe selective PPARα modulators.

Antrodia cinnamomea extract inhibits the proliferation of tamoxifen-resistant breast cancer cells through apoptosis and skp2/microRNAs pathway

BACKGROUND

Breast cancer is the most common cancer in women and affects 1.38 million women worldwide per year. Antiestrogens such as tamoxifen, a selective estrogen receptor (ER) modulator, are widely used in clinics to treat ER-positive breast tumors. However, remissions of breast cancer are often followed by resistance to tamoxifen and disease relapse. Despite the increasing understanding of the resistance mechanisms, effective regimens for treating tamoxifen-resistant breast cancer are limited. Antrodia cinnamomea is a traditional medicinal mushroom native only to Taiwan. In this study, we aimed to examine in vitro effect of antrodia cinnamomea in the tamoxifen-resistant cancer.

METHODS

Antrodia cinnamomea was studied for its biological activity against proliferation of tamoxifen-resistant breast cancer by XTT assay. Next, the underlying mechanism was studied by flow cytometry, qPCR and Western's blotting assay.

RESULTS

Our results revealed that the ethanol extract of antrodia cinnamomea (AC) can inhibit the growth of breast cancer cells, including MCF-7 cell and tamoxifen-resistant MCF-7 cell lines. Combination treatment with AC and 10- 6 M tamoxifen have the better inhibitory effect on the proliferation of tamoxifen-resistant MCF-7 cells than only AC did. AC can induce apoptosis in these breast cancer cells. Moreover, it can suppress the mRNA expression of skp2 (S-phase kinase-associated protein 2) by increasing the expressions of miR-21-5p, miR-26-5p, and miR-30-5p in MCF-7 and tamoxifen-resistant MCF-7 cells.

CONCLUSIONS

These results suggest that the ethanol extract of antrodia cinnamomea could be a novel anticancer agent in the armamentarium of tamoxifen-resistant breast cancer management. Moreover, we hope to identify additional pure compounds that could serve as promising anti-breast cancer candidates for further clinical trials.

Liraglutide reduces hepatic glucolipotoxicity‑induced liver cell apoptosis through NRF2 signaling in Zucker diabetic fatty rats

The primary aim of the present study was to evaluate the effects of liraglutide on glucolipotoxicity-induced liver cell apoptosis and the underlying mechanisms in Zucker diabetic fatty (ZDF) rats. The results revealed that liraglutide significantly decreased the body weight, hyperglycemia and hyperlipidemia of ZDF rats relative to those of Zucker lean (ZL) rats (P<0.05). Furthermore, the reduced liver cell apoptosis was observed in the ZDF rats following 6 weeks of liraglutide therapy. These data validated the beneficial effects of liraglutide on diabetic and obese ZDF rats. In addition, novel data was obtained that demonstrated that liraglutide treatment increased the expression of the antioxidant transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2), as well as the transcription of downstream target genes, including nicotinamide adenine dinucleotide phosphate quinone dehydrogenase 1 and heme oxygenase-1 (P<0.05). Additionally, serum and hepatic GSH and SOD levels increased following liraglutide therapy (P<0.05). Hence, it was proposed that liraglutide may enhance the antioxidant activity of liver cells by activating the NRF2 signaling pathway, thereby reducing liver cell apoptosis induced by glucolipotoxicity in ZDF rats, which may shed light on the application of liraglutide in the treatment of diabetes- and obesity-induced liver injury.

Kynurenic Acid Restores Nrf2 Levels and Prevents Quinolinic Acid-Induced Toxicity in Rat Striatal Slices

Kynurenic acid (KYNA) and quinolinic acid (QUIN) are metabolites produced in the degradation of tryptophan and have important neurological activities. KYNA/QUIN ratio changes are known to be associated with central nervous system disorders, such Alzheimer, Parkinson, and Huntington diseases. In the present study, we investigate the ability of KYNA in prevent the first events preceding QUIN-induced neurodegeneration in striatal slices of rat. We evaluated the protective effect of KYNA on oxidative status (reactive oxygen species production, antioxidant enzymes activities, lipid peroxidation, nitrite levels, protein and DNA damage, and iNOS immunocontent), mitochondrial function (mitochondrial mass, membrane potential, and respiratory chain enzymes), and Na⁺,K⁺-ATPase in striatal slices of rats treated with QUIN. Since QUIN alters the levels of Nrf2, we evaluated the influence of KYNA protection on this parameter. Striatal slices from 30-day-old Wistar rats were preincubated with KYNA (100 μM) for 15 min, followed by incubation with 100-μM QUIN for 30 min. Results showed that KYNA prevented the increase of ROS production caused by QUIN and restored antioxidant enzyme activities and the protein and lipid damage, as well as the Nrf2 levels. KYNA also prevented the effects of QUIN on mitochondrial mass and mitochondrial membrane potential, as well as the decrease in the activities of complex II, SDH, and Na⁺,K⁺-ATPase. We suggest that KYNA prevents changes in Nrf2 levels, oxidative imbalance, and mitochondrial dysfunction caused by QUIN in striatal slices. This study elucidates some of the protective effects of KYNA against the damage caused by QUIN toxicity.

Amelioration of carbon tetrachloride-induced hepatic injury by emulsified Antrodia extract

Objective(s):

Antrodia cinnamomea (AC) is found with anti-inflammatory and immunomodulatory biological activities. In this study, we investigated the anti-hepatitis effect of the emulsified AC extract from RO water or supercritical fluid CO₂ with ethanol co-solvent extract methods of AC preparations.

Materials and Methods:

Five groups of eight to ten weeks male rats with a count of ten for each group were studied to evaluate the protection of two kinds of AC extract from hepatic injury. Acute liver injury of rats was induced by injecting 40% carbon tetrachloride (CCl₄) 1 mg/kg intraperitoneally. Positive and negative control groups rats were perfused with CCl₄ or isotonic saline, respectively. Experimental groups received oral administration once/day of AC preparations before CCl₄ treatment: water AC extract (WAE group), or emulsified AC extract from supercritical fluid extraction (EAE group) for 5 days, and sacrificed on the 6^th day and the blood and liver samples were collected under chloral hydrate anesthesia. The anti-inflammatory, antioxidant markers, and relevant signaling pathways were measured (AST, ALT, ROS, IL-1, IL-6, NO, and COX-2, MAPKs, and caspase-3).

Results:

EAE at 50 mg/kg significantly decreased the serum AST, ALT, IL-1, IL-6, NO, and ROS levels. Both extracts reduced the activation of p-ERK in the liver samples, but EAE inhibited COX-2 and caspase-3 protein expression better than WAE. The EAE ameliorated CCl₄-induced hepatic injury significantly; as compared with WAE and the positive control.

Conclusion:

The hepatoprotection of EAE could be attributed to the antioxidant and anti-inflammatory effects of Antrodia.

Effects of Taiwanofungus camphoratus on non-specific and specific immune activities in mice

Taiwanofungus camphoratus is a precious medicinal fungus endemic to Taiwan and has been used as traditional medicine for a long time. Many pharmacological studies have revealed that T. camphoratus possessed various biological activities, such as immunomodulatory effects, anticancer activity and liver protective function. The aim of this study is to investigate the non-specific and antigen (ovalbumin [OVA])-specific immunomodulation effects of solid-state cultivated powder of T. camphoratus (Leader Antrodia cinnamomea [LAC]) in BABL/c male mice. In non-specific and antigen-specific immune function studies, 8-week-old mice were orally administered with LAC for 6 and 8 weeks, respectively. The results have shown that the proliferation of splenic immune cells, phagocytic activity of macrophages and cytolytic activity of natural killer cells were enhanced by LAC. Additionally, LAC increased the levels of IL-2, TNF-α, INF-γ, GM-CSF and serum OVA-IgG and OVA-IgM. These findings provided evidences that LAC had the immunomodulation effects on both antigen-specific and non-specific immune responses in mice.

Activation of Nrf2-mediated anti-oxidant genes by antrodin C prevents hyperglycemia-induced senescence and apoptosis in human endothelial cells

In the present study, we investigated the effects of antrodin C (ADC), a maleimide derivative isolated from mycelia of Antrodia cinnamomea, on high glucose (HG, 30 mM)-accelerated endothelial dysfunction in vitro. HG-induced cytotoxicity in human umbilical vein endothelial cells (HUVECs) was significantly ameliorated by ADC. In addition, treatment with ADC significantly prevented HG-induced senescence, growth arrest at the G₁-S transition phase and apoptosis in HUVECs. Moreover, the increased level of intracellular reactive oxygen species (ROS) under HG condition was significantly ameliorated by ADC. Further analysis revealed that ADC-mediated anti-oxidant effects were due to up-regulation of cellular anti-oxidant genes, such as HO-1 and NQO-1 via promotion of the transcriptional activity of Nrf2, which was further confirmed by the failure of ADC to protect HUVECs from HG-induced dysfunction under HO-1 inhibition or Nrf2 silencing. Furthermore, hyperosmotic glucose (HOG, 60 mM)-induced uncontrolled production of ROS, rapid apoptotic cell death and HUVEC injury were significantly prevented by ADC, whereas these preventive effects were barely observed in HO-1 inhibited or Nrf2 silenced cells. Taken together, these results suggest that ADC may represent a promising intervention in diabetic-associated cardiovascular diseases by activating the Nrf2-dependent cellular anti-oxidant defense system.

Hepatoprotective activities of Antrodia camphorata and its triterpenoid compounds against CCl4-induced liver injury in mice

ETHNOPHARMACOLOGY RELEVANCE

Antrodia camphorata (AC) is a rare and precious fungus indigenous to Taiwan used as a traditional medicine for the treatment of liver injury. Triterpenoids are the major bioactive constituents of A. camphorata and have been reported to possess hepatoprotective activities. To meet the increasing demand, artificial cultivation techniques have been developed.

AIM OF THE STUDY

This study aims to evaluate the hepatoprotective activities of AC samples derived from different cultivation techniques and to dissect the main active triterpenoid compounds.

MATERIALS AND METHODS

The ethanol extracts of five batches of AC samples, including wild growing fruiting bodies, cutting wood culture fruiting bodies, dish cultures, cutting wood culture mycelia, and submerged fermentation mycelia were orally administered (50mg/kg or 200mg/kg) to ICR mice for 7 days. On the last day, CCl₄ (0.2%, 7mL/kg, i.p.) was used to induce liver injury, and the activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined 24h after the injection. Moreover, a HepG2 cell model treated with CCl₄ (0.35%) was used to screen the protective activities of 29 AC triterpenoids. After incubation for 6h, viabilities of the cells were tested using MTS assay. The in vivo hepatoprotective activities of antcin B and antcin K were further studied on the mice model by ALT and AST tests and histopathologic examinations. To elucidate the mechanisms, the mRNA levels of iNOS, COX2, TNF-α and IL-1β, and the protein levels of NF-κB (p65/p-p65), iNOS and COX2 in liver tissues were determined.

RESULTS

The wild growing or cutting wood culture fruiting bodies, and the dish cultures of AC showed more potent activities than the mycelia (P<0.001). At 20μM, 16 of 29 triterpenoids showed significant protective activities, increasing HepG2 cell viability from 46% of the CCl₄ group to >90%. Antcin B and antcin K could dose-dependently (10 or 50mg/kg, 7 days, i.g.) decrease the serum levels of ALT and AST, and decrease the incidence of liver necrosis. The effects of 50mg/kg of antcin K or antcin B were almost identical to those of 100mg/kg silymarin. Furthermore, qRT-PCR and Western blotting analyses revealed they could down-regulate IL-1β, TNF-α, iNOS, COX-2 and NF-κB in liver tissues at both transcriptional and translational levels.

CONCLUSION

The results indicate that cultivation techniques remarkably affect the hepatoprotective activities of AC. Antcin K and antcin B are the major hepatoprotective compounds of A. camphorata, and the mechanism is related with anti-inflammation. Given its high natural abundance and good oral absorption, antcin K could be a promising drug candidate for liver injury.

Evaluation of the Cellular and Animal Models for the Study of Antioxidant Activity: A Review

The mechanisms of antioxidant activities of phytochemicals are highly complex, so various methods to study them have been developed. However, the diverse available methods show inconsistent results. Different stressors, cell models, and animal models have been used to evaluate the antioxidant properties of phytochemicals. However, the literature still lacks a summary of the effects of different stressors, cell models, and animal models on the evaluation of antioxidant activities. Therefore, the mechanisms of action of different oxidative stimuli and the characteristics of the available cell models and animal models are summarized in this review.

Cyanidin 3-O-β-Glucoside Ameliorates Ethanol-Induced Acute Liver Injury by Attenuating Oxidative Stress and Apoptosis: The Role of SIRT1/FOXO1 Signaling

BACKGROUND

The aim of this study was to examine the effects of Cyanidin 3-O-β-glucoside (C3G) on ethanol (EtOH)-induced acute liver injury in mice as well as in cultured hepatic cells exposed to EtOH, with a focus on the involvement of Silent Mating Type Information Regulation 2 Homolog 1 (SIRT1)/Forkhead fox-O-1 (FOXO1) signaling pathway, and to explore the underlying molecular mechanisms.

METHODS

C57BL/6 adolescent male mice were given EtOH via intraperitoneal injection for 2 consecutive days, and the changes in the livers were detected via hematoxylin-eosin staining. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by biochemical methods. Protein expression of SIRT1, FOXO1, acetylated FOXO1 (ac-FOXO1), GRP78, p-eukaryotic initiation factor-2 (eIF2α), and apoptosis (p-JNK, p-c-Jun, and Bax) parameters was determined by Western blot. Reactive oxygen species (ROS) was detected by flow cytometry. Human hepatocytes Chang cell line was used to assay cell apoptosis by Annexin V and propidium iodide. In addition, mRNA levels of SIRT1, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and monocyte chemoattractant protein 1 in liver tissues were detected by real-time polymerase chain reaction.

RESULTS

This study demonstrated that C3G (10 mg/kg) administration diminished EtOH-induced acute liver injury compared to control group, as evidenced by the significant decreases in ALT and AST levels. Pretreatment with C3G exerted anti-inflammatory effects as indicated by the decreased TNF-α and IL-6 levels, as well as decreased inflammatory foci and ballooning cells in liver tissue. The lessened hepatic injury was associated with enhanced SIRT1 protein expression and activity by C3G in vitro and in vivo. C3G treatment also provoked significant attenuation of endoplasmic reticulum stress parameters (GRP78, p-eIF2α), which was consistent with reduced levels of both p-c-Jun and Bax. Interestingly, EX527 inhibitor did not affect the protective function of C3G on alcohol-induced cell apoptosis. Moreover, alcohol exposure increased ROS level and decreased ac-FOXO1, while C3G intervention reversed this abnormality, and this may be related to SIRT1 activity by C3G.

CONCLUSIONS

Anthocyanin C3G has significant potency in antioxidant, anti-inflammatory, and anti-apoptotic effects on hepatocytes exposed to EtOH by modulating the SIRT1/FOXO1 signaling pathway. Our findings illustrate a novel and definitive therapeutic action of C3G and represent an economically feasible therapeutic intervention to treat alcoholic liver disease.

Naturally Occurring Nrf2 Activators: Potential in Treatment of Liver Injury

Oxidative stress plays a major role in acute and chronic liver injury. In hepatocytes, oxidative stress frequently triggers antioxidant response by activating nuclear erythroid 2-related factor 2 (Nrf2), a transcription factor, which upregulates various cytoprotective genes. Thus, Nrf2 is considered a potential therapeutic target to halt liver injury. Several studies indicate that activation of Nrf2 signaling pathway ameliorates liver injury. The hepatoprotective potential of naturally occurring compounds has been investigated in various models of liver injuries. In this review, we comprehensively appraise various phytochemicals that have been assessed for their potential to halt acute and chronic liver injury by enhancing the activation of Nrf2 and have the potential for use in humans.

A steroid like phytochemical Antcin M is an anti-aging reagent that eliminates hyperglycemia-accelerated premature senescence in dermal fibroblasts by direct activation of Nrf2 and SIRT-1

The present study revealed the anti-aging properties of antcin M (ANM) and elucidated the molecular mechanism underlying the effects. We found that exposure of human normal dermal fibroblasts (HNDFs) to high-glucose (HG, 30 mM) for 3 days, accelerated G0/G1 phase arrest and senescence. Indeed, co-treatment with ANM (10 µM) significantly attenuated HG-induced growth arrest and promoted cell proliferation. Further molecular analysis revealed that ANM blocked the HG-induced reduction in G1-S transition regulatory proteins such as cyclin D, cyclin E, CDK4, CDK6, CDK2 and protein retinoblastoma (pRb). In addition, treatment with ANM eliminated HG-induced reactive oxygen species (ROS) through the induction of anti-oxidant genes, HO-1 and NQO-1 via transcriptional activation of Nrf2. Moreover, treatment with ANM abolished HG-induced SIPS as evidenced by reduced senescence-associated β-galactosidase (SA-β-gal) activity. This effect was further confirmed by reduction in senescence-associated marker proteins including, p21CIP1, p16INK4A, and p53/FoxO1 acetylation. Also, the HG-induced decline in aging-related marker protein SMP30 was rescued by ANM. Furthermore, treatment with ANM increased SIRT-1 expression, and prevented SIRT-1 depletion. This protection was consistent with inhibition of SIRT-1 phosphorylation at Ser47 followed by blocking its upstream kinases, p38 MAPK and JNK/SAPK. Further analysis revealed that ANM partially protected HG-induced senescence in SIRT-1 silenced cells. A similar effect was also observed in Nrf2 silenced cells. However, a complete loss of protection was observed in both Nrf2 and SIRT-1 knockdown cells suggesting that both induction of Nrf2-mediated anti-oxidant defense and SIRT-1-mediated deacetylation activity contribute to the anti-aging properties of ANM in vitro. Result of in vivo studies shows that ANM-treated C. elegens exhibits an increased survival rate during HG-induced oxidative stress insult. Furthermore, ANM significantly extended the life span of C. elegans. Taken together, our results suggest the potential application of ANM in age-related diseases or as a preventive reagent against aging process.

Antrodia cinnamomea alleviates cisplatin-induced hepatotoxicity and enhances chemo-sensitivity of line-1 lung carcinoma xenografted in BALB/cByJ mice

Whereas cisplatin (cis-diamminedichloroplatinum II) is a first-line medicine to treat solid cancerous tumors, it often causes serious side effects. New medicines that have an equivalent or even better therapeutic effect but with free or less side effects than cisplatin are highly anticipated in cancer therapy. Recent reports revealed that Antrodia cinnamomea (AC) possesses hepatoprotective activity in addition to anticancer. In this study, we wanted to know whether AC enhances chemo-sensitivity of cisplatin and/or alleviates cisplatin-induced hepatotoxicity, as well as the underlying mechanisms thereof. Our results indicated that AC inhibited proliferation of line-1 lung carcinoma cells and rescued hepatic HepG2 cells from cisplatin-induced cell death in vitro. The fact is that AC and cisplatin synergized to constrain growth of line-1 lung carcinoma cells in BALB/cByJ mice. Quantitative real-time PCR further revealed that AC promoted expression of apoptosis-related genes, while it decreased expression of NF-κB and VEGF in tumor tissues. In liver, AC reduced cisplatin-induced liver dysfunctions, liver inflammation and hepatic apoptosis in addition to body weight restoration. In summary, AC is able to increase cisplatin efficacy by triggering expression of apoptosis-related genes in line-1 lung cancer cells as well as to protect liver from tissue damage by avoiding cisplatin-induced hepatic inflammation and cell death.

Hepatoprotective Effect of Wheat-Based Solid-State Fermented Antrodia cinnamomea in Carbon Tetrachloride-Induced Liver Injury in Rat

Antrodia cinnamomea (A. cinnamomea) is an indigenous medical fungus in Taiwan and has multiple biological functions, including hepatoprotective and immune-modulatory effects. Currently, the commercially available A. cinnamomea are mainly liquid- and solid-state fermented A. cinnamomea. However, the hepatoprotective effect of solid-state fermented A. cinnamomea has never been reported. Here we evaluate the ability of air-dried, ground and non-extracted wheat-based solid-state fermented A. cinnamomea (WFAC) to protect against carbon tetrachloride (CCl4)-induced hepatic injury in vivo. The results showed that oral administration of WFAC dose dependently (180, 540 and 1080 mg/kg) ameliorated the increase in plasma aspartate aminotransferase and alanine aminotransferase levels caused by chronic repeated CCl4 intoxication in rats. WFAC significantly reduced the CCl4-induced increase in hepatic lipid peroxidation levels and hydroxyproline contents, as well as reducing the spleen weight and water content of the liver. WFAC also restored the hepatic soluble protein synthesis and plasma albumin concentration in CCl4-intoxicated rats, but it did not affect the activities of superoxide dismutase, catalase, or glutathione peroxidase. In addition, a hepatic morphological analysis showed that the hepatic fibrosis and necrosis induced by CCl4 were significantly ameliorated by WFAC. Furthermore, the body weights of control rats and WFAC-administered rats were not significantly different, and no adverse effects were observed in WFAC-administered rats. These results indicate that WFAC is a nontoxic hepatoprotective agent against chronic CCl4-induced hepatic injury.

Lico A Enhances Nrf2-Mediated Defense Mechanisms against t-BHP-Induced Oxidative Stress and Cell Death via Akt and ERK Activation in RAW 264.7 Cells

Licochalcone A (Lico A) exhibits various biological properties, including anti-inflammatory and antioxidant activities. In this study, we investigated the antioxidative potential and mechanisms of Lico A against tert-butyl hydroperoxide- (t-BHP-) induced oxidative damage in RAW 264.7 cells. Our results indicated that Lico A significantly inhibited t-BHP-induced cytotoxicity, apoptosis, and reactive oxygen species (ROS) generation and reduced glutathione (GSH) depletion but increased the glutamate-cysteine ligase modifier (GCLM) subunit and the glutamate-cysteine ligase catalytic (GCLC) subunit genes expression. Additionally, Lico A dramatically upregulated the antioxidant enzyme heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2), which were associated with inducing Nrf2 nuclear translocation, decreasing Keap1 protein expression and increasing antioxidant response element (ARE) promoter activity. Lico A also obviously induced the activation of serine/threonine kinase (Akt) and extracellular signal-regulated kinase (ERK), but PI3K/Akt and ERK inhibitors treatment displayed clearly decreased levels of LicoA-induced Nrf2 nuclear translocation and HO-1 expression, respectively. Furthermore, Lico A treatment markedly attenuated t-BHP-induced oxidative damage, which was reduced by treatment with PI3K/Akt, ERK, and HO-1 inhibitors. Therefore, Lico A might have a protective role against t-BHP-induced cytotoxicity by modulating HO-1 and by scavenging ROS via the activation of the PI3K/Akt and ERK/Nrf2 signaling pathways.

2,3,5-Trimethoxy-4-cresol, an anti-metastatic constituent from the solid-state cultured mycelium of Antrodia cinnamomea and its mechanism

Antrodia cinnamomea is a valuable and unique edible fungus originating from the forests of Taiwan. In this study, an anti-metastatic compound, 2,3,5-trimethoxy-4-cresol (TMC), was isolated from the solid-state cultured mycelium of A. cinnamomea. According to the results obtained from cell wound healing, cell migration and invasion assays, TMC effectively suppressed movement, migration and invasion of lung cancer cells at the dosage of 5-40 μM, which was non-toxic to A549 cells. In addition, TMC reduced protein expression of Akt, MMP-2 and MMP-9 and enhanced E-cadherin and TIMP-1 protein expression, which are known to regulate cell adhesion, migration and invasion. Taken together, TMC effectively suppresses movement, migration and invasion of lung cancer cells, and achieves an anti-cancer metastasis effect.

Silymarin as a Natural Antioxidant: An Overview of the Current Evidence and Perspectives

Silymarin (SM), an extract from the Silybum marianum (milk thistle) plant containing various flavonolignans (with silybin being the major one), has received a tremendous amount of attention over the last decade as a herbal remedy for liver treatment. In many cases, the antioxidant properties of SM are considered to be responsible for its protective actions. Possible antioxidant mechanisms of SM are evaluated in this review. (1) Direct scavenging free radicals and chelating free Fe and Cu are mainly effective in the gut. (2) Preventing free radical formation by inhibiting specific ROS-producing enzymes, or improving an integrity of mitochondria in stress conditions, are of great importance. (3) Maintaining an optimal redox balance in the cell by activating a range of antioxidant enzymes and non-enzymatic antioxidants, mainly via Nrf2 activation is probably the main driving force of antioxidant (AO)  action of SM. (4) Decreasing inflammatory responses by inhibiting NF-κB pathways is an emerging mechanism of SM protective effects in liver toxicity and various liver diseases. (5) Activating vitagenes, responsible for synthesis of protective molecules, including heat shock proteins (HSPs), thioredoxin and sirtuins and providing additional protection in stress conditions deserves more attention. (6) Affecting the microenvironment of the gut, including SM-bacteria interactions, awaits future investigations. (7) In animal nutrition and disease prevention strategy, SM alone, or in combination with other hepatho-active compounds (carnitine, betaine, vitamin B₁₂, etc.), might have similar hepatoprotective effects as described in human nutrition.

Chitooligosaccharides inhibit ethanol-induced oxidative stress via activation of Nrf2 and reduction of MAPK phosphorylation

Chitooligosaccharides (COS) are hydrolyzed products of chitosan and have been proven to exhibit various biological functions. The aims of this study were to investigate the mechanisms underlying the hepatoprotective effects of COS against ethanol-induced oxidative stress in vitro. Human L02 normal liver cells were pretreated with COS (0.25, 0.5 and 1.0 mg/ml) and then hepatotoxicity was stimulated by the addition of ethanol (80 mM). Pretreatment with COS protected L02 cells from ethanol-induced cell cytotoxicity through inhibition of reactive oxygen species generation. Furthermore, ethanol-induced lipid peroxidation and glutathione depletion was inhibited by COS. The antioxidant potential of COS was correlated with the induction of antioxidant genes including HO-1, NQO1 and SOD via the transcriptional activation of nuclear factor erythroid-2‑related factor-2 (Nrf2). Additionally, the protective effects of COS against ethanol were blocked by Nrf2 knockdown. Moreover, signal transduction studies showed that COS was able to suppress the ethanol-induced phosphorylation of p38 MAPK, JNK and ERK. In conclusion, the COS-mediated activation of Nrf2 and reduction of MAPK phosphorylation may be important for its hepatoprotective action.