Review of natural products with hepatoprotective effects

The liver is one of the most important organs in the body,performing a fundamental role in the regulationof diverse processes,among which the metabolism,secretion,storage,and detoxification of endogenous and exogenous substances are prominent.Due to these functions,hepatic diseases continue to be among the main threats to public health,and they remain problems throughout the world.Despite enormous advances in modern medicine,there are no completely effective drugs that stimulate hepatic function,that offer complete protection of the organ,or that help to regenerate hepatic cells.Thus,it is necessary to identify pharmaceutical alternatives for the treatment of liver diseases,with the aim of these alternatives being more effective and less toxic.The use of some plants and the consumption of different fruits have played basic roles in human health care,and diverse scientific investigations have indicated that,in those plants and fruits so identified,their beneficial effects can be attributed to the presence of chemical compounds that are called phytochemicals.The present review had as its objective the collecting of data based on research conducted into some fruits(grapefruit,cranberries,and grapes)and plants[cactus pear(nopal)and cactus pear fruit,chamomile,silymarin,and spirulina],which are consumed frequently by humans and which have demonstrated hepatoprotective capacity,as well as an analysis of a resin(propolis)and some phytochemicals extracted from fruits,plants,yeasts,and algae,which have been evaluated in different models of hepatotoxicity.

Protective effect of some vitamins against the toxic action of ethanol on liver regeneration induced by partial hepatectomy in rats

AIM: To investigate the effects of vitamins (A, C and E) on liver injury induced by ethanol administration during liver regeneration in rats. METHODS: Male Wistar rats subjected to 70% partial hepatectomy were divided into five groups (groups 1-5). During the experiment, animals of Group 1 drank only water. The other four groups (2-5) drank 30 mL of ethanol/L of water. Group 3 additionally received vitamin A, those of group 4 vitamin C and those of group 5 received vitamin E. Subsequently serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin and bilirubin were measured colorimetrically. Lipid peroxidation (thiobarbituric-acid reactive substances, TBARS) both in plasma and liver was measured, as well as liver mass gain assessment and total DNA. RESULTS: Compared with sham group, serum AST and ALT increased significantly under ethanol treatment (43% and 93%, respectively, with P < 0.05). Vitamin C and vitamin E treatment attenuated the ethanol-induced increases in ALT and AST activity. Ethanol treatment also decreased serum albumin concentration compared to sham group (3.1 ± 0.4 g/dL vs 4.5 ± 0.2 g/dL; P < 0.05). During liver regeneration vitamins C and E significantly ameliorated liver injury for ethanol administration in hepatic lipid peroxidation (4.92 nmol/mg and 4.25 nmol/mg vs 14.78 nmol/mg, respectively, with P < 0.05). In association with hepatic injury, ethanol administration caused a significant increase in both hepatic and plasma lipid peroxidation. Vitamins (C and E) treatment attenuated hepatic and plasma lipid peroxidation. CONCLUSION: Vitamins C and E protect against liver injury and dysfunction, attenuate lipid peroxidation, and thus appear to be significantly more effective than vitamin A against ethanol-mediated toxic effects during liver regeneration.

Hepatoprotective effect of silymarin

The use of medicinal plants in treating illnesses has been reported since ancestral times.In the case of hepatic diseases,several species such as Silybum marianum,Phyllanthus niruri,and Panus giganteus(Berk.)have been shown to ameliorate hepatic lesions.Silymarin is a natural compound derived from the species Silybum marianum,which is commonly known as Milk thistle.This plant contains at least seven flavoligands and the flavonoid taxifolin.The hepatoprotective and antioxidant activity of silymarin is caused by its ability to inhibit the free radicals that are produced from the metabolism of toxic substances such as ethanol,acetaminophen,and carbon tetrachloride.The generation of free radicals is known to damage cellular membranes and cause lipoperoxidation.Silymarin enhances hepatic glutathione and may contribute to the antioxidant defense of the liver.It has also been shown that silymarin increases protein synthesis in hepatocytes by stimulating RNA polymerase I activity.A previous study on humans reported that silymarin treatment caused a slight increase in the survival of patients with cirrhotic alcoholism compared with untreated controls.

Effect of dichloromethylene diphosphonate on liver regeneration following thioacetamide-induced necrosis in rats

AIM: To study the effect of dichloromethylene diphos-phonate (DMDP), a selective Kupffer cell toxicant in reference to liver damage and postnecrotic liver regeneration in rats induced by sublethal dose thioacetamide (TA). METHODS: Rats, intravenously (iv ) pre-treated with a single dose of DMDP (10 mg/kg), were intraperitoneally (ip ) injected with TA 6.6 mmol/kg (per 500 mg/kg body weight). Hepatocytes were isolated from rats at 0, 24, 48 and 72 h following TA intoxication and blood and liver samples were obtained. To evaluate the mecha-nisms involved in the postnecrotic regenerative state, DNA distribution and ploidy time course were assayed in isolated hepatocytes. Circulating cytokine tumor necrosis factor-alpha (TNF-α) was assayed in serum and determined by reverse transcriptase-polymerase chain reaction in liver extract. RESULTS: The effect of DMDP induced noticeable changes in postnecrotic regeneration, causing an increased percentage of hepatocytes in the cell cycle S phase. The increase at 24 h in S1 population in rats pretreated with DMDP + TA was significantly (P < 0.05) different compared with that of the TA group (18.07% vs 8.57%). Hepatocytes increased their proliferation as a result of these changes. Also, TNF-α expression and serum level were increased in rats pre-treated with DMDP. Thus, DMDP pre-treatment reduced TA-induced liver injury and accelerated postnecrotic liver regeneration. CONCLUSION: These results demonstrate that Kupffer cells are involved in TA-induced liver, as well as in post-necrotic proliferative liver states.

Morphological and biochemical effects of weekend alcohol consumption in rats: Role of concentration and gender

AIM To examine the association between weekend alcohol consumption and the biochemical and histological alterations at two different concentrations of alcohol in both genders in rats.METHODS Wistar rats weighing 170-200 g were divided into groups as follows:(1) Control groups; and(2) weekend alcohol-consumption group: 2 d/weekly per 12 wk, at two different concentrations:(1) Group of males or females with a consumption of a solution of alcohol at 40%; and(2) group of males or females with a consumption of a solution of alcohol at 5%. At the end of the experiment, serum and liver samples were obtained. The following enzymes and metabolites were determined in serum: Alanine Aminotransferase(ALT), Aspartate Aminotransferase(AST), Lactate Dehydrogenase, and Gamma-Glutamyltransferase, and glucose, triglycerides, cholesterol, bilirubin, and albumin. Liver samples from each group were employed to analyze morphological abnormalities by light microscopy.RESULTS In all of the weekend alcohol-consumption groups, AST activity presented a significant, 10-fold rise. Regarding ALT activity, the groups with weekend alcohol consumption presented a significant increase that was six times greater. Bilirubin levels increased significantly in both groups of females. We observed a significant increase in the parameters of fatty change and inflammation due to weekend alcohol consumption. Only the group of females that consumed alcohol at 40% presented slight hepatocel ular disorganization CONCLUSION The results obtained herein provide solid evidence that weekend alcohol consumption gives rise to liver damage, demonstrated by biochemical and histological alterations, first manifested acutely, and prolonged weekend alcohol consumption can cause greater, irreversible damage.