Effect of silymarin on pyrogallol- and rifampicin-induced hepatotoxicity in mouse

Ehretia laevis mitigates paracetamol- induced hepatotoxicity by attenuating oxidative stress and inflammation in rats

Hepatotoxicity is caused due to intake of drug or any chemical above the therapeutic range or as overdose. Current therapies for the management of hepatotoxicity are associated with several side effects. The present study was envisaged to explore the hepatoprotective potential of Ehretia laevis (E. laevis) in paracetamol (PCM) induced hepatotoxicity. All the plant extracts and fractions were evaluated for antioxidant and antiproliferative potential using various in vitro assays. Hepatotoxicity was induced in rats using a standardized single oral dose of PCM (3 g/kg). The aqueous fraction of E. laevis (AFEL) exhibited significant antioxidant and antiproliferative activity as compared to methanol extract of E. laevis (MEEL) in vitro. Moreover, treatment with AFEL (25, 50 and 100 mg/kg) decreased serum hepatic markers, attenuate the oxidative stress, inflammation and histopathological changes. LC-MS analysis of AFEL showed the presence of rutin, quercetin and kaempferol. Rutin was found to be in higher concentration, therefore it was docked on TNF-α. Its overall binding mode supports its capability to make complex with TNF-α. The finding of the study suggested significant antioxidant, antiproliferative, and hepatoprotective potential of E. laevis in paracetamol induced hepatotoxicity which could be attributed to the presence of various polyphenols.

Oxidative Processes and Xenobiotic Metabolism in Plants: Mechanisms of Defense and Potential Therapeutic Implications

Plants are continuously exposed to environmental challenges, including pollutants, pesticides, and heavy metals, collectively termed xenobiotics. These substances induce oxidative stress by generating reactive oxygen species (ROS), which can damage cellular components such as lipids, proteins, and nucleic acids. To counteract this, plants have evolved complex metabolic pathways to detoxify and process these harmful compounds. Oxidative stress in plants primarily arises from the overproduction of hydrogen peroxide (H2O2), superoxide anions (O2•-), singlet oxygen (1O2), and hydroxyl radicals (•OH), by-products of metabolic activities such as photosynthesis and respiration. The presence of xenobiotics leads to a notable increase in ROS, which can result in cellular damage and metabolic disruption. To combat this, plants have developed a strong antioxidant defense mechanism that includes enzymatic antioxidants that work together to eliminate ROS, thereby reducing their harmful effects. In addition to enzymatic defenses, plants also synthesize various non-enzymatic antioxidants, including flavonoids, phenolic acids, and vitamins. These compounds effectively neutralize ROS and help regenerate other antioxidants, offering extensive protection against oxidative stress. The metabolism of xenobiotic substances in plants occurs in three stages: the first involves modification, which refers to the chemical alteration of xenobiotics to make them less harmful. The second involves conjugation, where the modified xenobiotics are combined with other substances to increase their solubility, facilitating their elimination from the plant. The third stage involves compartmentalization, which is the storage or isolation of conjugated xenobiotics in specific parts of the plant, helping to prevent damage to vital cellular functions. Secondary metabolites found in plants, such as alkaloids, terpenoids, and flavonoids, play a vital role in detoxification and the defense against oxidative stress. Gaining a deeper understanding of the oxidative mechanisms and the pathways of xenobiotic metabolism in plants is essential, as this knowledge can lead to the formulation of plant-derived strategies aimed at alleviating the effects of environmental pollution and enhancing human health by improving detoxification and antioxidant capabilities, as discussed in this review.

Neurotoxic and cardiotoxic effects of pyrogallol on catfish (Clarias gariepinus)

Pyrogallol, a botanical hydrolysable tannin, has diverse medical and industrial applications. Its impact on aquatic ecosystems and fish health has been previously studied, revealing histopathological, immunological, biochemical, and haematological alterations in African catfish (Clarias gariepinus). In this study, the neurotoxic potential of pyrogallol was assessed through a 15-day exposure of catfish to concentrations of 1, 5, or 10 mg/L. Enzyme activities such as acetylcholinesterase (AchE), monoamine oxidase (MAO), aldehyde oxidase (AO), and nitric oxide (NO) were measured in serum and brain, along with histopathological examinations in the brain and heart. Pyrogallol exposure led to decreased AchE activity in the brain and serum, increased serum MAO activity, elevated AO in both brain and serum, and suppressed NO levels. Morphological abnormalities and dose-dependent pathological alterations were observed in the brain and heart, including neuropile deformities, shrunken Purkinje cells, cardiomyocyte degeneration, and increased collagen fibers. This suggests that pyrogallol induces adverse effects in fish.

Immunotoxicological, histopathological, and ultrastructural effects of waterborne pyrogallol exposure on African catfish (Clariasgariepinus)

Pyrogallol is a naturally occurring polyphenol derived from natural plants, such as Acer rubrum and Eucalyptus sp. The current study was designed to evaluated pyrogallol-mediated toxicity at sublethal levels (1, 5, and 10 mg/L), derived from 96 h-LC50 values previously determined for African catfish (Clarias gariepinus). Immunotoxicological indices, histological, histochemical, and ultrastructural alterations in C. gariepinus were evaluated following a 15-day pyrogallol exposure. Pyrogallol decreased immune parameters [lysozyme activity (LYZ), immunoglobulin M (IgM), and phagocytic activity] and increased pro-inflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6) in the serum of C. gariepinus. In addition, histopathology analysis demonstrated that exposure to pyrogallol induced injury in the liver and spleen of fish. Cellular changes in the liver include hepatocyte hydropic degeneration, melanomacrophage, vacuolated hepatocytes, congested blood, severe structural deformation, and hemorrhage. In the spleen, ellipsoid structures, melanomacrophage centers, and infiltration of inflammatory cells were evident. Together, a high frequency of histopathological lesions was scored in both the liver and spleen of C. gariepinus, which showed a dose-dependent relationship between pyrogallol exposure and histopathological indices. Our data suggest that dysfunction in the immune system may be mediated by pyrogallol-induced changes in cytokines.

Oxidative stress, antioxidant defense responses, and histopathology: Biomarkers for monitoring exposure to pyrogallol in Clarias gariepinus

Pyrogallol promotes free radicals leading to oxidative stress and toxicity. There are however a lack of studies on oxidative stress and the antioxidant system of fish following exposure to pyrogallol. This study measured oxidative stress markers, antioxidant responses, and histological changes in catfish exposed to pyrogallol. Fish were divided into one of four experimental groups: control only, or 1, 5 or 10 mg/L pyrogallol. After 15 days, glutathione-S-transferase in the serum was decreased in fish exposed to either 5 or 10 mg/L pyrogallol relative to controls while superoxide dismutase and total antioxidant capacity were decreased significantly in fish exposed to 1, 5, or 10 mg/L pyrogallol. Conversely, catalase was increased in serum of fish exposed to 1, 5, or 10 mg/L pyrogallol compared to controls. The liver of fish treated with 1, 5, or 10 mg/L pyrogallol had significantly higher levels of oxidative stress markers (malondialdehyde, lipid peroxidation, hydroperoxide content, oxidised protein content, and DNA fragmentation %) that varied with concentration. Catfish exposed to either 1, 5, or 10 mg/L pyrogallol presented with notable histological alterations in the intestine, kidney, and muscles with prominent fibrosis, as intense deposition of collagen fibre was observed by Masson's trichrome staining. Overall, endpoints related to oxidative stress and antioxidant defence enzymes in fish may be early biomarkers of pyrogallol exposure and contamination in aquatic ecosystems. Additional studies should characterize oxidative stress indicators for their utility as biomarkers of effect.

Drug-induced liver injury and anti-hepatotoxic effect of herbal compounds: a metabolic mechanism perspective

BACKGROUND

Drug-induced liver injury (DILI) is the most challenging and thought-provoking liver problem for hepatologists owing to unregulated medication usage in medical practices, nutritional supplements, and botanicals. Due to underreporting, analysis, and identification issues, clinically evaluated medication hepatotoxicity is prevalent yet hard to quantify.

PURPOSE

This review's primary objective is to thoroughly compare pharmaceutical drugs and herbal compounds that have undergone clinical trials, focusing on their metabolic mechanisms contributing to the onset of liver illnesses and their hepatoprotective effects.

METHODS

The data was gathered from several online sources, such as PubMed, Scopus, Google Scholar, and Web of Science, using appropriate keywords.

RESULTS

The prevalence of conventional and herbal medicine is rising. A comprehensive understanding of the metabolic mechanism is necessary to mitigate the hepatotoxicity induced by drugs and facilitate the incorporation or substitution of herbal medicine instead of pharmaceuticals. Moreover, pre-clinical pharmacological research has the potential to facilitate the development of natural products as therapeutic agents, displaying promising possibilities for their eventual clinical implementation.

CONCLUSIONS

Acetaminophen, isoniazid, rifampicin, diclofenac, and pyrogallol have been identified as the most often reported synthetic drugs that produce hepatotoxicity by oxidative stress, inflammation, apoptosis, and fibrosis during the last several decades. Due to their ability to downregulate many factors (such as cytokines) and activate several enzyme/enzyme systems, herbal substances (such as Gingko biloba extract, curcumin, resveratrol, and silymarin) provide superior protection against harmful mechanisms which induce hepatotoxicity with fewer adverse effects than their synthetic counterparts.

A new insight into the hepatoprotective effect of sildenafil: The role of H2S

High-calorie diet, alcohol, and multiple drug use increase reactive oxygen species (ROS) and cause liver damage. ROS are crucial in the initiation/progression of liver diseases. Antioxidants have beneficial effects but produce clinically complex results. The hydrogen sulfide (H2S) pathway is considered a promising therapeutic target since it plays role in the pathogenesis/treatment of liver diseases. Sildenafil exerts antioxidant and hepatoprotective effects by increasing specific antioxidants such as superoxide dismutase, glutathione peroxidase, and regulating the Keap1/Nrf2 pathway which are common mechanisms underlying the effects of H2S. We aimed to determine if H2S has a role in the hepatoprotective and antioxidant effects of sildenafil. The effect of sildenafil on endogenous H2S production was elucidated with an H2S microsensor in the presence/absence of pyrogallol-induced oxidative stress and H2S synthesis inhibitor aminoxyacetic acid (AOAA) in the liver. The relation between the antioxidant effect of sildenafil and H2S was determined by luminol and lucigenin chemiluminescence. Sildenafil increased L-cysteine-induced H2S synthesis in the healthy liver and prevented the pyrogallol-induced reduction in H2S production. Sildenafil decreased the ROS production induced by pyrogallol and its protective effect was inhibited by AOAA. These results reveal that H2S is a new pharmacological mechanism of action of sildenafil on the liver. Therefore, sildenafil can be a potential therapeutic agent in treating many liver diseases in which H2S bioavailability is impaired. Additionally, the hepatoprotective effect of sildenafil by increasing endogenous H2S synthesis advances our knowledge in terms of developing H2S-targeting molecules.

Exposure to pyrogallol impacts the hemato-biochemical endpoints in catfish (Clarias gariepinus)

Pyrogallol is widely used in several industrial applications and can subsequently contaminate aquatic ecosystems. Here, we report for the first time the presence of pyrogallol in wastewater in Egypt. Currently, there is a complete lack of toxicity and carcinogenicity data for pyrogallol exposure in fish. To address this gap, both acute and sub-acute toxicity experiments were conducted to determine the toxicity of pyrogallol in catfish (Clarias gariepinus). Behavioral and morphological endpoints were evaluated, in addition to blood hematological endpoints, biochemical indices, electrolyte balance, and the erythron profile (poikilocytosis and nuclear abnormalities). In the acute toxicity assay, it was determined that the 96 h median-lethal concentration (96 h-LC50) of pyrogallol for catfish was 40 mg/L. In sub-acute toxicity experiment, fish divided into four groups; Group 1 was the control group. Group 2 was exposed to 1 mg/L of pyrogallol, Group 3 was exposed to 5 mg/L of pyrogallol, and Group 4 was exposed to 10 mg/L of pyrogallol. Fish showed morphological changes such as erosion of the dorsal and caudal fins, skin ulcers, and discoloration following exposure to pyrogallol for 96 h. Exposure to 1, 5, or 10 mg/L pyrogallol caused a significant decrease in hematological indices, including red blood cells (RBCs), hemoglobin, hematocrit, white blood cells (WBC), thrombocytes, and large and small lymphocytes in a dose-dependent manner. Several biochemical parameters (creatinine, uric acid, liver enzymes, lactate dehydrogenase, and glucose) were altered in a concentration dependent manner with short term exposures to pyrogallol. Pyrogallol exposure also caused a significant concentration-dependent rise in the percentage of poikilocytosis and nuclear abnormalities of RBCs in catfish. In conclusion, our data suggest that pyrogallol should be considered further in environmental risk assessments of aquatic species.

Evaluating Silymarin Extract as a Potent Antioxidant Supplement in Diazinon-Exposed Rainbow Trout: Oxidative Stress and Biochemical Parameter Analysis

This study aimed to investigate the effects of diazinon on fish, focusing on hepatotoxic biomarkers and the potential protective effects of silymarin supplementation. One hundred eighty rainbow trout were randomly assigned to four groups: control, diazinon exposed (0.1 mg L-1), silymarin supplemented (400 mg kg-1), and diazinon + silymarin. Blood samples and liver tissue were collected after 7, 14, and 21 days of exposure to analyze biochemical parameters and oxidative biomarkers. Diazinon exposure in fish resulted in liver damage, as indicated by increased antioxidant enzyme activities in the hepatocytes. Silymarin showed the potential to mitigate this damage by reducing oxidative stress and restoring enzyme activities. Nevertheless, diazinon increased creatine phosphokinase activity, which may not be normalized by silymarin. Exposure to diazinon increased glucose, triglyceride, and cholesterol levels, whereas total protein, albumin, and globulin levels were significantly decreased in fish. However, silymarin controlled and maintained these levels within the normal range. Diazinon increased creatinine, urea, uric acid, and ammonia contents. Silymarin could regulate creatinine, urea, and uric acid levels while having limited effectiveness on ammonia excretion. Furthermore, diazinon increased malondialdehyde in hepatocytes, whereas administration of silymarin could restore normal malondialdehyde levels. Overall, silymarin showed potential as a therapeutic treatment for mitigating oxidative damage induced by diazinon in fish, but its effectiveness on creatine phosphokinase, glutathione reductase, and ammonia may be limited.

Naringenin protects hepato-renal tissues against antituberculosis drugs induced toxic manifestations by modulating interleukin-6, insulin like growth factor-1, biochemical and ultra-structural integrity

BACKGROUND

The antituberculosis drugs (ATDs), isoniazid, rifampicin, pyrazinamide and ethambutol prompt extreme hepatic and renal damage during treatment of tuberculosis. The present study aimed to investigate protective potential of naringenin against ATDs induced hepato-renal injury.

METHODS

Rats were administered with ATDs (pyrazinamide; 210, ethambutol; 170, isoniazid; 85, rifampicin; 65 mg/kg b.wt) orally for 8 weeks (3 days/week) followed by naringenin at three different doses (10, 20 and 40 mg/kg b.wt) conjointly for 8 weeks (3 days/week alternately to ATDs administration) and silymarin (50 mg/kg b.wt) as positive control.

RESULTS

Exposure to ATDs caused significant increase in interleukin-6 (IL-6), triglycerides, cholesterol, bilirubin whereas depletion in insulin like growth factor-1 (IGF-1), albumin and glucose in serum. Endogenous antioxidant enzymes glutathione reductase (GR), glutathione peroxidase (GPx) and glucose-6-phosphate-dehydrogenase (G-6-PDH) were diminished in liver and kidney tissues with parallel increase in triglycerides, cholesterol, microsomal LPO and aniline hydroxylase (CYP2E1 enzyme). Ultra-structural observations of liver and kidney showed marked deviation in plasma membranes of various cellular and sub-cellular organelles after 8 weeks of exposure to ATDs.

CONCLUSIONS

Conjoint treatment of naringenin counteracted ATDs induced toxic manifestations by regulating IL-6, IGF-1, CYP2E1, biochemical and ultra-structural integrity in a dose dependent manner. Naringenin has excellent potential to protect ATDs induced hepato-renal injury by altering oxidative stress, modulation of antioxidant enzymes, serum cytokines and ultra-structural changes.

Hepatoprotective effect of Physalis divaricata in paracetamol induced hepatotoxicity: In vitro, in silico and in vivo analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Physalis divaricata D. Don. is an erect weed of family Solanaceae. The root extract of this plant is used by the indigenous communities of Sub-Himalayan region of Uttarakhand, India for the treatment of liver disorders.

AIM OF THE STUDY

To evaluate hepatoprotective potential of P. divaricata in paracetamol (PCM) induced hepatotoxicity in rats.

MATERIALS AND METHODS

The dried roots of P. divaricata were subjected to extraction using different solvents. The chloroform extract, methanol extract and bioactive aqueous fraction of methanol extract were evaluated for hepatoprotective effect. After initial in vitro screening, all extracts were screened for hepatoprotective potential in PCM (3 g/kg p.o) induced hepatotoxicity. Following PCM administration, extracts were administered orally for 7 days in increasing dose concentrations. All the animals were euthanized on eighth day, serum and liver tissues were collected and subjected to various biochemical and histopathological analysis. Aqueous fraction of methanol extract was further analyzed using LC- MS analysis.

RESULTS

Methanol extract and its bioactive aqueous fraction exhibited significant and better in vitro antioxidant and antiproliferative activity as compared to chloroform extract. PCM treatment caused hepatotoxicity as assessed by altered levels of various hepatic biomarkers (increase in the levels of ALT, AST, ALP, albumin, triglycerides, cholesterol, TBARS, and AOPPs as well as decrease in GSH and TrxR levels) along with histopathological changes (portal to portal bridging, necrosis, and inflammation). Methanolic extract (200, 400 and 800 mg/kg) and its aqueous fraction treatment (25, 50 and 100 mg/kg) significantly restored elevated hepatic biomarkers, oxidative stress, and protected normal hepato-architecture. LC-MS analysis of aqueous fraction showed presence of rutin and kaempferol. In silico analysis further showed the capability of rutin to make complex with TNF-α and block its interaction with the target site.

CONCLUSION

Aqueous fraction showed maximum hepatoprotective potential as conceived through in vitro and in vivo studies. Presence of rutin may explain hepatoprotective potential of P. divaricata.

Pyrogallol and Fluconazole Interact Synergistically In Vitro against Candida glabrata through an Efflux-Associated Mechanism

Candida glabrata is currently the first or second most commonly encountered non-albicans Candida species worldwide. The potential severity of Candida resistance mandates the discovery of novel antifungal agents, including those that can be used in combination therapies. In this study, we evaluated the in vitro interactions of pyrogallol (PG) and azole drugs against 22 clinical C. glabrata isolates. The potential mechanism underlying the synergism between PG and fluconazole (FLC) was investigated by the rhodamine 6G efflux method and quantitative reverse transcription (qRT)-PCR analysis. In susceptibility tests, PG showed strong synergism with FLC, itraconazole (ITC), and voriconazole (VRC), with fractional inhibitory concentration index values of 0.18 to 0.375 for PG+FLC, 0.250 to 0.750 for PG+ITC, and 0.141 to 0.750 for PG+VRC. Cells grown in the presence of PG+FLC exhibited reduced rhodamine 6G extrusion and significantly downregulated expression of the efflux-related genes CgCDR1, CgCDR2, and CgPDR1 compared with cells grown in the presence of PG or FLC alone. PG did not potentiate FLC when tested against a ΔCgpdr1 strain. Restoration of a functional CgPDR1 allele also restored the synergism. These results indicate that PG is an antifungal agent that synergistically potentiates the activity of azoles. Furthermore, PG appears to exert its effects by inhibiting efflux pumps and downregulating CgCDR1, CgCDR2, and CgPDR1, with CgPDR1 probably playing a crucial role in this process.

Assessment of hepatic functions, hematopoietic cytokines and haematological parameters in people occupationally exposed to volatile petroleum hydrocarbons

Humans are occupationally exposed to volatile petroleum hydrocarbons through inhalation and ingestion. To access the effect of exposure to volatile hydrocarbons, hematopoietic cytokines, haematological parameters and hepatic functions were assayed for in 100 subjects. Male participants showed significant increase (p < 0.05) in erythropoietin, interleukin-3, alanine transaminase (ALT), alkaline phosphatase (ALP), mean cell hemoglobin concentration (MCHC), mean cell volume (MCV) and significant decrease (p < 0.05) in mean cell hemoglobin (MCH). Female participants showed significant increase (p < 0.05) in interleukin-3, ALT, AST, ALP, MCHC, MCV and significant decrease (p < 0.05) in MCH, platelets, hemoglobin and hematocrit compared to their controls. Exposure to volatile petroleum hydrocarbons raised the absolute red blood cell indices and liver enzymes and could stimulate combined increase in the release of erythropoietin and interleukin-3 leading to ineffective hematopoiesis.

Modulation of rifampicin-induced hepatotoxicity using poly(lactic-co-glycolic acid) nanoparticles: a study on rat and cell culture models

Aim: Hepatotoxicity is the most serious adverse effect of rifampicin (RIF). We aimed to investigate the potential hepatoprotective effect of mannose-functionalized poly(lactic-co-glycolic acid)(PLGA)/RIF nanoparticles (NPs) in rats as a possible promising approach to minimize RIF-induced hepatotoxicity. Materials & methods: Mannose-functionalized PLGA/RIF NPs were fabricated and characterized in vitro, then the hepatoprotective effect of optimized NPs was studied on rat and cell culture models. Results: Following intraperitoneal administration of RIF NPs into rats, highly significant differences in levels of serum transaminases and oxidative stress markers, associated with significant differences in expression of Bax and Bcl-2 genes between NP- and free RIF-treated groups, revealing the hepatoprotective potential of NPs. Conclusion: RIF NPs may represent a promising therapeutic approach for tuberculosis via reducing dose frequency and consequently, RIF-induced hepatotoxicity.

Silymarin and Cancer: A Dual Strategy in Both in Chemoprevention and Chemosensitivity

Silymarin extracted from milk thistle consisting of flavonolignan silybin has shown chemopreventive and chemosensitizing activity against various cancers. The present review summarizes the current knowledge on the potential targets of silymarin against various cancers. Silymarin may play on the system of xenobiotics, metabolizing enzymes (phase I and phase II) to protect normal cells against various toxic molecules or to protect against deleterious effects of chemotherapeutic agents on normal cells. Furthermore, silymarin and its main bioactive compounds inhibit organic anion transporters (OAT) and ATP-binding cassettes (ABC) transporters, thus contributing to counteracting potential chemoresistance. Silymarin and its derivatives play a double role, namely, limiting the progression of cancer cells through different phases of the cycle-thus forcing them to evolve towards a process of cell death-and accumulating cancer cells in a phase of the cell cycle-thus making it possible to target a greater number of tumor cells with a specific anticancer agent. Silymarin exerts a chemopreventive effect by inducing intrinsic and extrinsic pathways and reactivating cell death pathways by modulation of the ratio of proapoptotic/antiapoptotic proteins and synergizing with agonists of death domains receptors. In summary, we highlight how silymarin may act as a chemopreventive agent and a chemosensitizer through multiple pathways.

Medicinal plants: Adjunct treatment to tuberculosis chemotherapy to prevent hepatic damage

The effectiveness of herbs for the management of chemically induced hepatotoxicity has been discussed by many researchers. However, there is a paucity of compressive literature on the significance of hepatoprotective plants for the management of anti-TB drug induced toxicity. Anti-TB drugs have been reported to causes hepatic damage, due to which, many patients across the globe discontinued the treatment. Medicinal plants have multiple therapeutic effects. The assessment of biological activity of plants against Mycobacterium and its use for hepatic recovery provides an effective treatment approach. Traditionally used medicinal plants are the rich source of phytochemicals and secondary metabolites. These compounds can restore normal function, enzymatic activity and structure of hepatic cells against anti-TB drug induced hepatotoxicity. The present review covers comprehensive details on different hepatoprotective and antimycobacterial plants studied during past few decades so that potential adjuvants can be studied for Tuberculosis chemotherapy.

Effects of phenolic compounds from aqueous extract of Trifolium repens against acetaminophen-induced hepatotoxicity in mice

The aqueous extract of Trifolium repens (TR) leaves was analyzed for the phenolic profile using reversed phase HPLC-DAD and administered to mice against acetaminophen-induced hepatoxicity. Twenty-four phenolic compounds were identified and quantified. The highest amounts present were of kaempferol-3-(caffeoyldiglucoside)-7-glucoside (983.7 µg/ml), followed by p-coumaroyl-4-glucoside (905.6 µg/ml) and daidzein-O-sulfate (808.3 µg/ml). The aqueous extract was administered to mice along with acetaminophen at different doses. Acetaminophen was found to significantly alter body weight, serum biochemistry, and hematological indices of mice, which were ameliorated by the co-administration of aqueous extract. Liver histopathological studies revealed that acetaminophen significantly induced toxicity, while TR aqueous extract provides curative functions. Lipid peroxidation and total reduced glutathione in the liver were also normalized by the aqueous extract of TR. The aqueous extract of TR was rich in important phenolic compounds, which can be used as a source of beneficial bioactive compounds with hepato-protective function. PRACTICAL APPLICATIONS: Acetaminophen has been widely used as antipyretic and analgesic. However, the major complication reported is hepatotoxicity. Synthetic or conventional drugs used for hepatic diseases or against hepatotoxicity are insufficient and causes severe side effects. For this purpose, traditional medicinal plants or nutraceuticals are used to decrease in the side effects of different hepatotoxic medicine are demanding. Food and neutraceuticals are rich in important polyphenolic compounds which are the best antioxidants. This study was aimed to evaluate the phenolic composition of aqueous extract of Trifolium repens and its potential protective action against the acetaminophen-induced toxicity in mice. This study showed for the first time that the aqueous extract of TR was protective against the hepatotoxicity induced by acetaminophen.

Microbial metabolites of proanthocyanidins reduce chemical carcinogen-induced DNA damage in human lung epithelial and fetal hepatic cells in vitro

Seven selected microbial metabolites of proanthocyanidins (MMP), 3-phenylpropionic, 4-hydroxyphenyl acetic, 3-(4-hydroxyphenyl) propionic, p-coumaric, benzoic acid, pyrogallol (PG), and pyrocatechol (PC) were evaluated for their ability to reduce chemical carcinogen-induced toxicity in human lung epithelial cells (BEAS-2B) and human fetal hepatic cells (WRL-68). Cells pre-treated with MMP were exposed to a known chemical carcinogen, 4-[(acetoxymethyl) nitrosamino]-1-(3-pyridyl)-1-butanone (NNKOAc) to assess MMP-mediated cytoprotection and reduction of DNA damage. PG in BEAS-2B and PC in WRL-68 cells mitigated the NNKOAc-induced cytotoxicity. Pre-incubation of PG depicted significant protection against NNKOAc-induced DNA damage in BEAS-2B cells. PC in WRL-68 cells showed similar activity. To understand the mechanisms of PG- and PC-mediated DNA damage reduction, the effect on DNA damage response (DDR) proteins, cellular reactive oxygen species (ROS), total antioxidant capacity (TAC), glutathione peroxidase (GPx), and caspase activity were studied. PG and PC alter the DDR and may promote ATR-Chk1 and ATM-Chk2 pathways, respectively. Cellular oxidative stress induced by NNKOAc was mitigated by PG and PC through enhanced GPx expression and TAC. PG and PC suppressed the activation of the extrinsic apoptotic pathway (caspase 3 and 8) provoked by NNKOAc. MMP are beneficial in chemoprevention by reducing cellular DNA damage.

Modulatory and regenerative potential of transplanted bone marrow-derived mesenchymal stem cells on rifampicin-induced kidney toxicity

INTRODUCTION

Anti-tuberculosis agent rifampicin is extensively used for its effectiveness. Possible complications of tuberculosis and prolonged rifampicin treatment include kidney damage; these conditions can lead to reduced efficiency of the affected kidney and consequently to other diseases. Bone marrow-derived mesenchymal stem cells (BMMSCs) can be used in conjunction with rifampicin to avert kidney damage; because of its regenerative and differentiating potentials into kidney cells. This research was designed to assess the modulatory and regenerative potentials of MSCs in averting kidney damage due to rifampicin-induced kidney toxicity in Wistar rats and their progenies. BMMSCs used in this research were characterized according to the guidelines of International Society for Cellular Therapy.

METHODS

The rats (male and female) were divided into three experimental groups, as follows: Group 1: control rats (4 males & 4 females); Group 2: rats treated with rifampicin only (4 males & 4 females); and Group 3: rats treated with rifampicin plus MSCs (4 males & 4 females). Therapeutic doses of rifampicin (9 mg/kg/day for 3-months) and MSCs infusions (twice/month for 3-months) were administered orally and intravenously respectively. At the end of the three months, the animals were bred together to determine if the effects would carry over to the next generation. Following breeding, the rats were sacrificed to harvest serum for biochemical analysis and the kidneys were also harvested for histological analysis and quantification of the glomeruli size, for the adult rats and their progenies.

RESULTS

The results showed some level of alterations in the biochemical indicators and histopathological damage in the rats that received rifampicin treatment alone, while the control and stem cells treated group showed apparently normal to nearly normal levels of both bio-indicators and normal histological architecture.

CONCLUSIONS

Intravenous administration of MSCs yielded sensible development, as seen from biochemical indicators, histology and the quantitative cell analysis, hence implying the modulatory and regenerative properties of MSCs.

Selected hepatoprotective herbal medicines: Evidence from ethnomedicinal applications, animal models, and possible mechanism of actions

Insight into the hepatoprotective effects of medicinally important plants is important, both for physicians and researchers. Main reasons for the use of herbal medicine include their lesser cost compared with conventional drugs, lesser undesirable drug reactions and thus high safety, and reduced side effects. The present review focuses on the composition, pharmacology, and results of experimental trials of selected medicinal plants: Silybum marianum (L.) Gaertn., Glycyrrhiza glabra, Phyllanthus amarus Schumach. & Thonn., Salvia miltiorrhiza Bunge., Astragalus membranaceus (Fisch.) Bunge, Capparis spinosa (L.), Cichorium intybus (L.), Solanum nigrum (L.), Sapindus mukorossi Gaertn., Ginkgo biloba (L.), Woodfordia fruticosa (L.) Kurz, Vitex trifolia (L.), Schisandra chinensis (Turcz.) Baill., Cuscuta chinensis (Lam.), Lycium barbarum, Angelica sinensis (Oliv.) Diels, and Litsea coreana (H. Lev.). The probable modes of action of these plants include immunomodulation, stimulation of hepatic DNA synthesis, simulation of superoxide dismutase and glutathione reductase to inhibit oxidation in hepatocytes, reduction of intracellular reactive oxygen species by enhancing levels of antioxidants, suppression of ethanol-induced lipid accumulation, inhibition of nucleic acid polymerases to downregulate viral mRNA transcription and translation, free radical scavenging and reduction of hepatic fibrosis by decreasing the levels of transforming growth factor beta-1, and collagen synthesis in hepatic cells. However, further research is needed to identify, characterize, and standardize the active ingredients, useful compounds, and their preparations for the treatment of liver diseases.

Prevalence of chromosomal aberrations in Argentinean agricultural workers

Little is known about biosecurity measures and toxic effects during pesticide application in the province of Jujuy, Argentina, particularly concerning the protective measures and mixture of pesticides used by rural workers. We carried out an observational study of agricultural workers from Jujuy (76 exposed subjects and 53 controls) to investigate the prevalence of chromosomal aberrations (CAs) in human lymphocytes as well as the activity level of acetylcholinesterase (AChE) in red blood cell erythrocytes. Whole blood samples (5 mL) were collected in heparinized Vacutainer tubes for cytogenetic analysis and erythrocyte cholinesterase activity determination according to Ellman's method. Cytogenetic results showed a significant CA increase in pesticide-exposed individuals as compared with controls (4.20 ± 0.15 vs. 1.00 ± 0.05, respectively; p < 0.001), suggesting that pesticides are clastogenic agents causing DNA damage. Erythrocyte cholinesterase activity was significantly lower in exposed individuals, evidencing the possible occurrence of perturbations in blood as well as neurotoxicity in pesticide sprayers. These results suggest the need for periodic biomonitoring of these biomarkers together with education and training of occupational workers for the safe application of potentially harmful pesticides.

Comparison of efficacy of folic acid and silymarin in the management of antiepileptic drug induced liver injury: a randomized clinical trial

BACKGROUND

Liver injury associated with antiepileptic drugs accounts for a large proportion of drug-induced liver injuries (DILI) in children. Although withdrawal of the causative agent is the only proved treatment for DILI, in some clinical situations it is not possible. Recent studies have reported promising results of using hepatoprotective drugs with antioxidant actions for the management of DILI. This study aimed to evaluate the efficacy of folic acid versus silymarin treatment in relation to decreasing liver enzymes in patients with DILI due to antiepileptic therapy.

METHODS

This randomized, open-label, clinical trial evaluated 55 children with epilepsy who were on antiepileptic treatment and experienced DILI. The children were randomized to receive either silymarin (5 mg/kg per day) or folic acid (1 mg per day) for one month and were followed up for three months.

RESULTS

Liver enzymes significantly decreased in both groups. The decrease trend in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were stronger in the folic acid group compared to silymarin group (P=0.04 and P=0.007, respectively). At the end of the study patients in the folic acid group had significantly lower ALT (P=0.04), AST (P=0.02), and gamma-glutamyl transferase (GGT) (P<0.001) levels and also higher percentage of normal ALT (30.7% vs 3.4%, P=0.009) and AST (42.3% vs 0%, P<0.001), and GGT (23.1% vs 0%, P=0.008) values compared to the patients in the silymarin group. No rebound elevations in ALT, AST and GGT levels or adverse reactions were noted in neither of the study groups.

CONCLUSION

Although both treatments were safe and effective in decreasing liver enzymes, folic acid seems to be superior to silymarin in the management of DILI.

Aronia melanocarpa Extract Ameliorates Hepatic Lipid Metabolism through PPARγ2 Downregulation

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Studies have demonstrated that anthocyanin-rich foods may improve hyperlipidemia and ameliorate hepatic steatosis. Here, effects of Aronia melanocarpa (AM), known to be rich of anthocyanins, on hepatic lipid metabolism and adipogenic genes were determined. AM was treated to C57BL/6N mice fed with high fat diet (HFD) or to FL83B cells treated with free fatty acid (FFA). Changes in levels of lipids, enzymes and hormones were observed, and expressions of adipogenic genes involved in hepatic lipid metabolism were detected by PCR, Western blotting and luciferase assay. In mice, AM significantly reduced the body and liver weight, lipid accumulation in the liver, and levels of biochemical markers such as fatty acid synthase, hepatic triglyceride and leptin. Serum transaminases, indicators for hepatocyte injury, were also suppressed, while superoxide dismutase activity and liver antioxidant capacity were significantly increased. In FL83B cells, AM significantly reduced FFA-induced lipid droplet accumulation. Protein synthesis of an adipogenic transcription factor, peroxisome proliferator-activated receptor γ2 (PPARγ2) was inhibited in vivo. Furthermore, transcriptional activity of PPARγ2 was down-regulated in vitro, and mRNA expression of PPARγ2 and its downstream target genes, adipocyte protein 2 and lipoprotein lipase were down-regulated by AM both in vitro and in vivo. These results show beneficial effects of AM against hepatic lipid accumulation through the inhibition of PPARγ2 expression along with improvements in body weight, liver functions, lipid profiles and antioxidant capacity suggesting the potential therapeutic efficacy of AM on NAFLD.

NQO1 and CYP450 reductase decrease the systemic exposure of rifampicin-quinone and mediate its redox cycle in rats

Rifampicin (RIF) is used in regimens for infections caused by Mycobacteria accompanied by serious adverse reactions. Rifampicin-quinone (RIF-Q) is a major autoxidation product of RIF. It is not clear whether RIF-Q plays a role in RIF induced adverse reactions. Investigation of the systemic exposure of RIF-Q is helpful to better understand the role of RIF-Q in RIF induced adverse reactions. In this study, a simple and reproducible high performance liquid chromatography-mass spectrometry (LC-MS) method involving a procedure to prevent the RIF from oxidation for simultaneous quantification of RIF and RIF-Q in rat plasma has been developed and validated, and applied to elucidate the systemic exposure of RIF-Q in rats. The pharmacokinetics data showed that the systemic exposure of RIF-Q was very low (0.67% of RIF, AUC_0-24) in rats after oral administration of RIF. However, RIF-Q may undergo the redox cycle in vivo by the evidence that the majority of RIF-Q was reduced to RIF after an oral dose of RIF-Q. Pretreatment with the NAD(P)H: quinone oxidoreductase 1 (NQO1) specific inhibitor dicoumarol and/or cytochrome P450 reductase (CPR) inhibitor diphenyleneiodonium suppressed the redox cycle and significantly increased the systemic exposure of RIF-Q. The inhibitors also attenuated the redox cycle induced reactive oxygen species formation and cytotoxicity in RIF-Q-treated HepG2 cells. These results indicate that NQO1 and CPR play an important role in redox cycle of RIF-Q and may thus contribute to RIF-induced adverse reactions.

Drug-Induced Liver Toxicity and Prevention by Herbal Antioxidants: An Overview

The liver is the center for drug and xenobiotic metabolism, which is influenced most with medication/xenobiotic-mediated toxic activity. Drug-induced hepatotoxicity is common and its actual frequency is hard to determine due to underreporting, difficulties in detection or diagnosis, and incomplete observation of exposure. The death rate is high, up to about 10% for drug-induced liver damage. Endorsed medications represented >50% of instances of intense liver failure in a study from the Acute Liver Failure Study Group of the patients admitted in 17 US healing facilities. Albeit different studies are accessible uncovering the mechanistic aspects of medication prompted hepatotoxicity, we are in the dilemma about the virtual story. The expanding prevalence and effectiveness of Ayurveda and natural products in the treatment of various disorders led the investigators to look into their potential in countering drug-induced liver toxicity. Several natural products have been reported to date to mitigate the drug-induced toxicity. The dietary nature and less adverse reactions of the natural products provide them an extra edge over other candidates of supplementary medication. In this paper, we have discussed the mechanism involved in drug-induced liver toxicity and the potential of herbal antioxidants as supplementary medication.

A Review on Hepatoprotective and Immunomodulatory Herbal Plants

The liver is the most important organ that plays an important role in maintaining various physiological processes in the body. Hepatitis is an inflammation of the liver and is characterized by the presence of inflammatory cells in the tissue of the organ. There are five main viruses, referred to as types A, B, C, D, and E. These five types are of the greatest concern because of the burden of illness and death. Liver injury or liver dysfunction is a major health problem that challenges not only health care professionals but also the drug regulatory agencies and the pharmaceutical industry. Herbal medicines have been used in the treatment of liver disease for a long time. The immune system is the part of body that diagnoses the pathogen by using a specific receptor to reveal immediate response by the activation of immune components cells, chemokines, and cytokines, and also the release of the inflammatory mediator. They potentiate and modulate the immune system. The plant-derived phytoconstituents (polysaccharides, proteins and flavanoids, lignans, rotenoids, etc.) stimulate the immune system and maintained hepatic diseases. There are a number of hepatoprotective and immunomodulatory herbs that have been reported. The present review is aimed at compiling data on promising phytochemicals from hepatoprotective and immunomodulatory herbs.

Expression of hepatic cytochrome P450s and UDP-glucuronosyltransferases in PXR and CAR double humanized mice treated with rifampicin

Nuclear receptor humanized mice models have been developed to predict regulation of drug metabolizing enzyme by xenobiotics. However, limited information is available concerning xenobiotic-induced regulation of drug metabolizing enzymes in multiple nuclear receptor humanized mice. The present study investigated the hepatic regulation of cytochrome P450s (CYPs) and UDP-glucuronosyltransferases (UGTs) in the pregnane X receptor (PXR) and the constitutive androstane receptor double humanized mice treated with rifampicin (RIF; 10mg/kg) for 4 days. RIF increased hepatic microsomal protein and total CYP contents, and CYP reductase activity in the humanized mice, but not in normal mice. Moreover, hepatic induction of Cyp2b10, Cyp2c, and Cyp3a11 were observed only in the RIF-treated humanized mice, suggesting that the humanized mice are sensitive to RIF with respect to the regulation of the hepatic CYP system. Hepatic UGT activities using estradiol, serotonin, and mefenamic acid, but not chenodeoxycholic acid as substrates, increased in the RIF-treated humanized mice, and the glucuronidation activities of estradiol and chenodeoxycholic acid increased in RIF-treated normal mice. These results raise the possibility that a PXR-independent mechanism may be involved in hepatic regulation of UGTs by RIF.

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.

Nicotine-encapsulated poly(lactic-co-glycolic) acid nanoparticles improve neuroprotective efficacy against MPTP-induced parkinsonism

For some instances of Parkinson disease (PD), current evidence in the literature is consistent with reactive oxygen species being involved in the etiology of the disease. The management of PD is still challenging owing to its ambiguous etiology and lack of permanent cure. Because nicotine offers neuroprotection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonism, the neuroprotective efficacy of nicotine-encapsulated poly(lactic-co-glycolic) acid (PLGA) nanoparticles and the underlying mechanism of improved efficacy, if any, over bulk nicotine were assessed in this study. The selected indicators of oxidative stress, dopaminergic neurodegeneration and apoptosis, were measured in both in vitro and rodent models of parkinsonism in the presence or absence of "nanotized" or bulk nicotine. The levels of dopamine and its metabolites were measured in the striatum, nicotine and its metabolite in the nigrostriatal tissues while the immunoreactivities of tyrosine hydroxylase (TH), metallothionein-III (MT-III), inducible nitric oxide synthase (iNOS) and microglial activation were checked in the substantia nigra of controls and treated mice. GSTA4-4, heme oxygenase (HO)-1, tumor suppressor protein 53 (p53), caspase-3, lipid peroxidation (LPO), and nitrite levels were measured in the nigrostriatal tissues. Nicotine-encapsulated PLGA nanoparticles improved the endurance of TH-immunoreactive neurons and the number of fiber outgrowths and increased the mRNA expression of TH, neuronal cell adhesion molecule, and growth-associated protein-43 over bulk against 1-methyl-4-phenyl pyridinium ion-induced degeneration in the in vitro model. MPTP reduced TH immunoreactivity and levels of dopamine and its metabolites and increased microglial activation, expression of GSTA4-4, iNOS, MT-III, HO-1, p53, and caspase-3, and levels of nitrite and LPO. Whereas both bulk nicotine and nicotine-encapsulated PLGA nanoparticles modulated the changes toward controls, the modulation was more pronounced in nicotine-encapsulated PLGA nanoparticle-treated parkinsonian mice. The levels of nicotine and cotinine were elevated in nicotine-encapsulated PLGA nanoparticle-treated PD mouse brain compared with bulk. The results obtained from this study demonstrate that nanotization of nicotine improves neuroprotective efficacy by enhancing its bioavailability and subsequent modulation in the indicators of oxidative stress and apoptosis.

Protective effects of metallothionein on isoniazid and rifampicin-induced hepatotoxicity in mice

Isoniazid (INH) and Rifampicin (RFP) are widely used in the world for the treatment of tuberculosis, but the hepatotoxicity is a major concern during clinical therapy. Previous studies showed that these drugs induced oxidative stress in liver, and several antioxidants abated this effect. Metallothionein (MT), a member of cysteine-rich protein, has been proposed as a potent antioxidant. This study attempts to determine whether endogenous expression of MT protects against INH and RFP-induced hepatic oxidative stress in mice. Wild type (MT+/+) and MT-null (MT−/−) mice were treated intragastrically with INH (150 mg/kg), RFP (300 mg/kg), or the combination (150 mg/kg INH +300 mg/kg RFP) for 21 days. The results showed that MT−/− mice were more sensitive than MT+/+ mice to INH and RFP-induced hepatic injuries as evidenced by hepatic histopathological alterations, increased serum AST levels and liver index, and hepatic oxidative stress as evidenced by the increase of MDA production and the change of liver antioxidant status. Furthermore, INH increased the protein expression of hepatic CYP2E1 and INH/RFP (alone or in combination) decreased the expression of hepatic CYP1A2. These findings clearly demonstrate that basal MT provides protection against INH and RFP-induced toxicity in hepatocytes. The CYP2E1 and CYP1A2 were involved in the pathogenesis of INH and RFP-induced hepatotoxicity.

Hepatoprotective effect of ethanolic extract of Curcuma longa on thioacetamide induced liver cirrhosis in rats

Background

Hepatology research has focused on developing traditional therapies as pharmacological medicines to treat liver cirrhosis. Thus, this study evaluated mechanisms of the hepatoprotective activity of Curcuma longa rhizome ethanolic extract (CLRE) on thioacetamide-induced liver cirrhosis in rats.

Methods

The hepatoprotective effect of CLRE was measured in a rat model of thioacetamide-induced liver cirrhosis over 8 weeks. Hepatic cytochrome P450 2E1 and serum levels of TGF-β1 and TNF-α were evaluated. Oxidative stress was measured by malondialdehyde, urinary 8-hydroxyguanosine and nitrotyrosine levels. The protective activity of CLRE free-radical scavenging mechanisms were evaluated through antioxidant enzymes. Protein expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins in animal blood sera was studied and confirmed by immunohistochemistry of Bax, Bcl2 proteins and proliferating cell nuclear antigen.

Results

Histopathology, immunohistochemistry and liver biochemistry were significantly lower in the Curcuma longa-treated groups compared with controls. CLRE induced apoptosis, inhibited hepatocytes proliferation but had no effect on hepatic CYP2E1 levels.

Conclusion

The progression of liver cirrhosis could be inhibited by the antioxidant and anti-inflammatory activities of CLRE and the normal status of the liver could be preserved.

Pesticides-induced biochemical alterations in occupational North Indian suburban population

Pesticides are used in agriculture to protect crops from insects–pests. Most of the field workers of North Indian population are exposed to commonly used insecticides. In the present study, pesticides induced oxidative stress as well as alterations in the level of acetylcholinesterase (AChE) in a total of 70 male healthy agricultural sprayers, exposed to pesticides for about 5 years, were studied and the results were compared with 70 controls. The levels of antioxidant enzymes (superoxide dismutase, CAT, glutathione- S-transferase and glutathione peroxidase), AChE, lipid peroxidation and glutathione (GSH) contents were determined in their blood erythrocytes (red blood cells (RBCs)). The results indicated significant increase in the levels of malondialdehyde as well as the activities of antioxidant enzymes in pesticide-exposed individuals. The levels of GSH, RBC-AChE activity and plasma antioxidant potential were sharply decreased when compared with control subjects. The ferric-reducing ability of plasma (FRAP) assay was carried out to evaluate the antioxidant potential of pesticide in exposed as well as healthy controls. A significant positive correlation was observed between plasma FRAP value and the activity of AChE from RBCs in pesticides sprayers. Furthermore, these results were supported by enhanced messenger RNA expressions of cytochrome P450 isoform 2E1 (CYP2E1) and gutathione- S-transferase isoform pi (GST-pi) in the white blood cells of the randomly selected pesticide-exposed individuals. The decreased GSH level in human red blood cells accompanied by increase in the levels of the activities of antioxidative enzymes and over expressions of CYP2E1 and GST-pi is an indicative of oxidative stress in pesticides-exposed individuals. The reduced activity of AChE indicates possible occurrence of perturbations in blood as well as neurotoxicity in pesticide sprayers.

Resveratrol ameliorates methotrexate-induced hepatotoxicity in rats via inhibition of lipid peroxidation

Hepatotoxicity is one of the major complications of methotrexate (MTX) therapy. This study was carried out to evaluate the possible protective effect of resveratrol (trans-3,5,4'-trihydroxystilbene, RVT) against MTX-induced hepatotoxicity. Rats were randomly divided into four groups as control, MTX treated (7 mg/kg/day, intraperitoneally (i.p.), once daily for 3 consecutive days), MTX + RVT treated (20 mg/kg/day, i.p.), and RVT treated. First dose of RVT was administrated 3 days before the MTX injection and continued for 3 days. Histopathology of liver was evaluated by light microscopy. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) were used as biochemical markers of MTX-induced hepatic injury. The levels of thiobarbituric acid reactive substances (TBARS, a marker of lipid peroxidation) and activities of hepatic antioxidant enzymes such as catalase (CAT) and glutathione-S-transferase (GST) were used to analyze the oxidative stress-mediated lipid peroxidation in liver sections. Our results showed that MTX administration significantly increased ALT, ASP, and ALP levels. TBARS, CAT, and GST levels were also markedly increased in liver after MTX administration. RVT treatment significantly prevented MTX-induced hepatotoxicity, as indicated by AST, ALT, and ALP levels and liver histopathology. Moreover, administration of RVT significantly decreased the elevated levels of TBARS and activities of CAT and GST in the liver compared to MTX-treated group. These results revealed that RVT may have a protective effect against MTX-induced hepatotoxicity by inhibiting oxidative stress-mediated lipid peroxidation. Consequently, RVT treatment might be a promising strategy against MTX-induced hepatotoxicity.

Biochemical and molecular mechanisms of N-acetyl cysteine and silymarin-mediated protection against maneb- and paraquat-induced hepatotoxicity in rats

Oxidative stress is one of the major players in the pathogenesis of maneb (MB) and paraquat (PQ)-induced disorders. N-acetyl cysteine (NAC), a glutathione (GSH) precursor and silymarin (SIL), a naturally occurring antioxidant, encounter oxidative stress-mediated cellular damage. The present study was aimed to investigate the effects of NAC and SIL against MB and/or PQ-induced hepatotoxicity in rats. The levels of hepatotoxicity markers - alanine aminotransaminase (ALT), aspartate aminotransaminase (AST) and total bilirubin, histological changes, oxidative stress indices, phase I and phase II xenobiotic metabolizing enzymes - cytochrome P450 (CYP) and glutathione S-transferase (GST) and pro-inflammatory molecules - inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured in animals treated with MB and/or PQ in the presence or absence of NAC and SIL. MB and/or PQ augmented ALT, AST, total bilirubin, lipid peroxidation and nitrite contents and catalytic activities of superoxide dismutase and glutathione peroxidase however, the GSH content was attenuated. NAC and SIL restored the above-mentioned alterations towards basal levels but the restorations were more pronounced in SIL treated groups. Similarly, MB and/or PQ-mediated histopathological symptoms and changes in the catalytic activities/expressions of CYP1A2, CYP2E1, iNOS, TNF-α, and IL-1β were alleviated by NAC and SIL. Conversely, MB and/or PQ-induced GSTA4-4 expression/activity was further increased by NAC/SIL and glutathione reductase activity was also increased. The results obtained thus suggest that NAC and SIL protect MB and/or PQ-induced hepatotoxicity by reducing oxidative stress, inflammation and by modulating xenobitic metabolizing machinery and SIL seems to be more effective.

Extract of the plant Cotinus coggygria Scop. attenuates pyrogallol-induced hepatic oxidative stress in Wistar rats

To examine the protective potential of the Cotinus coggygria Scop. methanol extract, Wistar rats were treated with the hepatotoxic compound pyrogallol, which possesses a potent ability to generate free radicals and induce oxidative stress. The ability of the extract to counteract the oxidative stress was examined in rats that were injected with the extract intraperitoneally (500 mg·(kg body weight)(-1)) either 2 or 12 h before the pyrogallol treatment. The extract possesses a reducing activity in vitro and an ability to chelate the ferrous ion both in vivo and in vitro. Application of the extract prior to pyrogallol treatment led to a decrease in the levels of thiobarbituric acid-reactive substances, aspartate aminotransferase, and alanine aminotransferase, increased activities of antioxidant enzymes and attenuation of DNA damage, as well as increased Akt activity and inhibition of NF-κB protein expression. Treatment with the extract 12 h prior to pyrogallol administration was more effective in suppressing pyrogallol-induced oxidative damage than the 2 h pretreatment. Extract administration promoted an increase in acute phase reactants haptoglobin and α(2)-macroglobulin that was short of a full-fledged acute phase response. Administration of the extract considerably improved the markers of oxidative stress, thus revealing a potential hepatoprotective activity. Our results suggest that Akt activation, NF-κB inhibition, and induction of the acute phase play important roles in mediating hepatic protection by the extract. The greater effectiveness of the 12 h pretreatment with extract points to the important role that preconditioning assumes in improving resistance to subsequent exposure to oxidative stress.

Therapeutic efficacy of silymarin and naringenin in reducing arsenic-induced hepatic damage in young rats

We investigated the effects of silymarin and naringenin in counteracting arsenic-induced hepatic oxidative stress post exposure. Male wistar rats were chronically exposed to sodium arsenite for eight months followed by oral treatment with silymarin and naringenin (50 mg/kg each) for 15 consecutive days to evaluate hepatic damage and antioxidant potential. Our results demonstrate a significant decrease in hepatic GSH levels, SOD and catalase activities and an increase in GST and TBARS levels after arsenic administration. Silymarin or naringenin administration increased GSH levels and was beneficial in the recovery of altered SOD and catalase activity besides significantly reducing blood and tissue arsenic concentration. Our results point to the antioxidant potential of these flavonoids, which might be of benefit in the clinical recovery of subject exposed to arsenic. These flavonoids can be incorporated into the diet or co-supplemented during chelation treatment, and thus may afford a protective effect against arsenite-induced cytotoxicity.

Melatonin or silymarin reduces maneb- and paraquat-induced Parkinson's disease phenotype in the mouse

Oxidative stress is reported as one of the most widely accepted mechanisms of maneb (MB)- and paraquat (PQ)-induced nigrostriatal dopaminergic neurodegeneration leading to the Parkinson's disease (PD) phenotype. The study investigated the effects of silymarin, an antioxidant of plant origin, and melatonin, an indoleamine produced in all species, in MB- and PQ-induced mouse model of PD. The mice were treated intraperitoneally daily with silymarin (40mg/kg) or melatonin (30mg/kg) along with respective controls for 9wk. Subsets of these animals were also treated with MB (30mg/kg) and PQ (10mg/kg), twice a week, for 9wk, 2hr after silymarin/melatonin treatment. Locomotor activities along with striatal dopamine content, tyrosine hydroxylase (TH) immunoreactivity, number of degenerating neurons, lipid peroxidation and nitrite content were estimated. Additionally, mRNA expression of vesicular monoamine transporter, cytochrome P-450 2E1 (CYP2E1), and glutathione-S-transferase A4-4 (GSTA4-4), catalytic activities of CYP2E1 and GSTA4-4 and protein expressions of unphosphorylated and phosphorylated p53 (p53 and P-p53), Bax and caspase 9 were measured in control and MB- and PQ-treated mice with either silymarin or melatonin treatments. Silymarin/melatonin significantly offset MB- and PQ-mediated reductions in locomotor activities, dopamine content, TH immunoreactivity, VMAT 2 mRNA expression and the expression of p53 protein. Silymarin/melatonin attenuated the increases in lipid peroxidation, number of degenerating neurons, nitrite content, mRNA expressions of cytochrome P-450 2E1 (CYP2E1) and GSTA4-4, catalytic activities of CYP2E1 and GST and P-p53, Bax and caspase 9 protein expressions. The results demonstrate that silymarin and melatonin offer nigrostriatal dopaminergic neuroprotection against MB- and PQ-induced PD by the modulation of oxidative stress and apoptotic machinery.

Genetic polymorphisms of cytochrome P450 and glutathione S-transferase associated with antituberculosis drug-induced hepatotoxicity in Chinese tuberculosis patients

This study was designed to investigate the association of genetic polymorphisms of cytochrome P450 subtype 2E1 (CYP2E1) and glutathione S-transferase mu 1 (GSTM1) with susceptibility to antituberculosis drug-induced hepatotoxicity (ADIH) in Chinese tuberculosis patients. All patients were treated with a combination of isoniazid, rifampicin, pyrazinamide and ethambutol. Genomic DNA from 104 patients with ADIH and 111 without ADIH was analysed for the frequency of CYP2E1 RsaI and GSTM1 RsaI genotypes by polymerase chain reaction and restriction fragment length polymorphism. The association of polymorphisms with susceptibility to ADIH was calculated using the chi(2)-test and logistic regression analysis. The CYP2E1 RsaI polymorphisms were significantly associated with ADIH and the c1/c1 genotype was an independent risk factor for ADIH. Compared with the GSTM1 RsaI present genotype, the GSTM1 RsaI null genotype tended to increase susceptibility to ADIH, but the association with ADIH was not significant. The results indicate that CYP2E1 RsaI genotype c1/c1 is a potential risk factor for ADIH in the Chinese population. The tendency of the GSTM1 RsaI null genotype to increase susceptibility to ADIH needs further study.

Involvement of multiple molecular events in pyrogallol-induced hepatotoxicity and silymarin-mediated protection: evidence from gene expression profiles

In this study, the involvement of various molecular events in pyrogallol-mediated hepatotoxicity was deciphered by differential mRNA transcription profiles of control and pyrogallol treated mice liver. The modulatory effects of silymarin on pyrogallol-induced differentially expressed transcripts were also looked into. Swiss albino mice were treated with or without pyrogallol. In some set of experiments, mice were also treated with silymarin 2 h prior to pyrogallol. Total RNA was isolated from liver and polyadenylated RNA was reverse-transcribed into Cye 3 or Cye 5 labelled cDNA. Equal amounts of labelled cDNA from two different groups were mixed and hybridized with mouse 15 k array. The hybridized arrays were scanned, analyzed and the expression level of each transcript was calculated. The differential expression was validated by quantitative real time polymerase chain reaction. Comparative transcription pattern showed an alteration in the expression of 183 transcripts (150 up-regulated and 33 down-regulated) associated with oxidative stress, cell cycle, cytoskeletal network, cell-cell adhesion, extra-cellular matrix, inflammation, apoptosis, cell-signaling and intermediary metabolism in pyrogallol-exposed liver and silymarin pre-treatment modulated the expression of many of these transcripts. Results obtained thus suggest that pyrogallol induces multiple molecular events leading to hepatotoxicity and silymarin effectively counteracts pyrogallol-mediated alterations.