Antioxidant Levels In Liver Research Articles

Epigallocatechin gallate effectively ameliorates fluoride-induced oxidative stress and DNA damage in the liver of rats

Environmental exposure to sodium fluoride (NaF) compounds is a worldwide health concern. Epigallocatechin gallate (EGCG) is a green tea catechin found in a variety of green tea preparations. The intention of this study was to investigate the hepatoprotective role of EGCG in NaF-intoxicated rats. Rats were orally treated with NaF alone (25 mg·(kg body mass)(-1)·day(-1)) or plus EGCG at different doses (20, 40, and 80 mg·(kg body mass)(-1)·day(-1)) for 4 weeks. Hepatotoxicity of NaF was determined by increased levels of serum hepatospecific markers and total bilirubin, along with increased levels of thiobarbituric acid reactive substances, lipid hydroperoxides, protein carbonyl content, and conjugated dienes. The hepatotoxic nature of NaF was further evidenced by the decreased activity of enzymatic and nonenzymatic antioxidant levels in liver. NaF-treated rats also showed increased DNA damage and fragmentation in hepatocytes. Administration of EGCG (40 mg·(kg body mass)(-1)) to NaF-intoxicated rats significantly recuperated the distorted biochemical indices, DNA damage, and pathological changes in the liver tissue. Thus, the results of the present study clearly demonstrate that EGCG has strong free radical scavenging, antioxidant, and antigenotoxic properties that protect against NaF-induced oxidative hepatic injury in rats.

High levels of liver antioxidants are associated with life-history strategies characteristic of slow growth and high survival rates in birds

Antioxidants have a large potential to coevolve with life-histories because of their capacity to counteract the negative effects of free radicals on fitness. However, only a few studies have explored the association between antioxidant levels and life-history strategies comparing a large number of species. Here we used an extensive dataset of 125 species of birds to investigate the association between concentrations of antioxidants (carotenoids and vitamin E) in the liver, which is the main storage organ for fat-soluble antioxidants, and life-history and morphology. We found that high liver antioxidant concentrations were associated with life-history strategies characterized by "live slow, die old", in clear contrast to previous studies reporting a relationship between high plasma antioxidants and life-histories characterized by "live fast, die young". Thus, high carotenoid concentrations were present in species with large body, brain and egg sizes, high absolute metabolic rate and a resident lifestyle, while high vitamin E concentrations were present in species with large brain size and long life span and incubation period. Our results indicate that antioxidants and life-histories coevolve, and that this may be mediated by positive fitness consequences of the accumulation of liver antioxidants, as species with higher antioxidant levels live longer.

Hepatoprotective activity of Tribulus terrestris extract against acetaminophen-induced toxicity in a freshwater fish (Oreochromis mossambicus)

The potential protective role of Tribulus terrestris in acetaminophen-induced hepatotoxicity in Oreochromis mossambicus was investigated. The effect of oral exposure of acetaminophen (500 mg/kg) in O. mossambicus at 24-h duration was evaluated. The plant extract (250 mg/kg) showed a remarkable hepatoprotective activity against acetaminophen-induced hepatotoxicity. It was judged from the tissue-damaging level and antioxidant levels in liver, gill, muscle and kidney tissues. Further acetaminophen impact induced a significant rise in the tissue-damaging level, and the antioxidant level was discernible from the enzyme activity modulations such as glutamate oxaloacetic transaminase, glutamate pyruvic transaminase, alkaline phosphatase, acid phosphatase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, lipid peroxidase and reduced glutathione. The levels of all these enzymes have significantly (p < 0.05) increased in acetaminophen-treated fish tissues. The elevated levels of these enzymes were significantly controlled by the treatment of T. terrestris extract (250 kg/mg). Histopathological changes of liver, gill and muscle samples were compared with respective controls. The results of the present study specify the hepatoprotective and antioxidant properties of T. terrestris against acetaminophen-induced toxicity in freshwater fish, O. mossambicus.

Amelioration of Alcohol-Induced Hepatotoxicity and Oxidative Stress in Rats by Acorus Calamus

ABSTRACTThe protective effect of a methanolic extract (ME) of Acorus calamus against alcohol-induced hepatotoxicity and oxidative stress was studied in rats. The in vitro assays using DPPH and ABTS showed a strong antioxidant activity of the extract with the total polyphenolic content of 156 mg/g. Chronic ethanol administration causes an increase in oxidative stress and tissue injury with decreased antioxidant status. In this study, continuous administration of ethanol (7.9 g/kg body weight/day) for a period of 6 weeks resulted in a significant (p < .001) increase in the levels of serum aspartate aminotransferase, serum alanine aminotransferase, alkaline phospahatase, and bilirubin with the decreased level of total antioxidant status. Moreover, the levels of lipid peroxidation markers (malondialdehyde and hydroperoxides) as well as protein carbonyl content were also increased (p < .001), whereas the levels of non-enzymic antioxidants (glutathione, vitamin C, and vitamin E) decreased significantly in the liver tissues of ethanol-administered control rats. Pretreatment of rats with ME at doses of 300 and 600 g/kg body weight before alcohol administration significantly reduced the hepatic marker enzymes, level of lipid peroxidation, and protein oxidation, and increased the enzymatic and non-enzymatic antioxidant levels in liver. These observations were supplemented by histopathological examination of liver sections. Overall, the present study shows that the administration of ME ameliorates the antioxidant status as well as protects against the toxic effects of ethanol in rats, thereby suggesting its use as an effective botanical supplement for hepatoprotection.

Hepatoprotection by carotenoids in isoniazid–rifampicin induced hepatic injury in rats

This study evaluates the hepatoprotective effect of carotenoids against isoniazid (INH) and rifampicin (RIF). Thirty-six adult rats were divided into the following 4 groups: (1) control group treated with normal saline; (2) INH + RIF group treated with 50mg·(kg body mass)-1·day-1 of INH and RIF each; (3) INH + RIF+ carotenoids group treated with 50mg·(kg body mass)-1·day-1 of INH and RIF each and 10mg·(kg body mass)-1·day-1 of carotenoids; and (4) carotenoids group treated with 10mg·(kg body mass)-1·day-1 of carotenoids for 28days intragastrically. Oxidative stress and antioxidant levels in liver and blood, liver histology and change in transaminases were measured in all the above-mentioned groups. There was an increase in lipid peroxidation with a reduction in thiols, catalase, and superoxide dismutase (SOD) in the liver and blood of rats accompanied by an increase in transaminases, bilirubin, and alkaline phosphatase. Treatment with carotenoids along with INH + RIF partially reversed lipid peroxidation, thiols, catalase, and SOD in the liver and blood of rats. Elevated levels of the enzymes in serum were also reversed partially by this treatment. The degree of necrosis, portal triaditis, and inflammation were also lowered in the carotenoids group. In conclusion, carotenoids supplementation in INH + RIF treated rats showed partial protection.

Hepatoprotective properties of Morinda pubescens J.E. Smith (Morinda tinctoria Roxb.) fruit extract

The present study evaluated the hepatoprotective properties of Morinda pubescens fruit extract against d-galactosamine (d-GalN)-induced liver injury in rats. The fruit extract of M. pubescens was administrated orally at 200 mg/kg of body weight daily once for 21 days and at 21st day, d-GalN (500 mg/kg of body weight) was injected intraperitoneally in rats, to induce liver damage. In d-GalN administrated rats, significant increase in the levels of serum marker enzymes and lipid peroxidation (LPO) in liver and decreased serum and liver antioxidant levels were observed. Pre-treatment with fruit extract to rats reduced the elevated levels of serum marker enzymes and also improves the levels of fucose, ceruloplasmin, and uric acid. Administration of M. pubescens fruit extract prevented increase of LPO and alteration in iron content in experimental animals, besides, considerably increased the levels of glutathione (GSH) and vitamin E when compared to d-GalN intoxicated animals. The present results suggest that the M. pubescens fruit extract has liver-protective property against d-GalN-induced liver injury in rats, which was further confirmed by histopathological studies. The hepatoprotective potentials of fruits of M. pubescens may be due to the presence of phenols and alkaloids, as analyzed by preliminary phytochemical analysis of fruit extract.

Modulatory effect of seabuckthorn leaf extract on oxidative stress parameters in rats during exposure to cold, hypoxia and restraint (C-H-R) stress and post stress recovery

This study was carried out to examine the antioxidative potential, if any, of seabuckthorn leaf aqueous extract, administered orally in rats at a dose of 100 mg kg(-1) both in single and five doses, 30 min before cold (5 degrees C)-hypoxia (428 mm Hg)-restraint (C-H-R) exposure. The effect of the extract was studied on lipid peroxidation and antioxidant parameters in liver and gastrocnemius muscle of rats on attaining the rectal temperature (T(rec)) of 23 degrees C during C-H-R exposure and after recovery (T(rec)37 degrees C) from C-H-R-induced hypothermia. In untreated rats exposed to C-H-R, there was a significant increase in malondialdehyde (MDA) levels in liver and muscle along with decreased activity of catalase (CAT) and glutathione-S-transferase (GST) in liver and muscle. Single- and five-dose extract treatment restricted the increase in liver and muscle MDA levels and five doses of extract treatment further improved the levels of liver antioxidants, viz. reduced glutathione (GSH), on recovery of T(rec)37 degrees C, increased superoxide dismutase (SOD) during exposure and recovery, normalized CAT activity in liver during C-H-R exposure and an increase on recovery of T(rec)37 degrees C. The decreasing pattern of liver and muscle GST levels both in single-dose and five-dose extract treated rats was similar to that in untreated rats. Results suggested that supplementation with seabuckthorn extract helps to reduce oxidative stress in liver and muscle of rats during C-H-R exposure and post-stress recovery.

Protective effect of selenium-polysaccharides from the mycelia of Coprinus comatus on alloxan-induced oxidative stress in mice

We investigated the effect of selenium-polysaccharide (SPS) isolated from selenium-enriched mycelia of Coprinus comatus on hypoglycaemic, hypolipidemic and antioxidant activities in diabetic mice. Compared with untreated diabetic mice, the administration of SPS for 20 days caused a significant decrease (p < 0.05) in blood glucose levels. Simultaneously, the alteration in lipid metabolism was partially attenuated as evidenced by decreased serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL) levels and by increased high-density lipoprotein cholesterol (HDL) concentration in diabetic mice (p < 0.05). In addition, the SPS caused a significant decrease (p < 0.05) in the level of malondialdehyde (MDA) and a significant increase (p < 0.05) in the activities of enzymic antioxidants and the levels of non-enzymic antioxidants in liver and kidney of diabetic mice. Furthermore, the effects of SPS was more potent than that of polysaccharide (PS) from mycelia of C. comatus at the same dose.

Protein Synthesis and Antioxidant Capacity in Aging Mice: Effects of Long‐Term Voluntary Exercise

Exercise increases metabolic rate and the production of reactive oxygen species (ROS) but also elevates protein turnover. ROS cause damage to macromolecules (e.g., proteins) and thereby contribute to aging. Protein turnover removes and replaces damaged proteins. The balance between these two responses may underlie beneficial effects of physical activity on aging. Effects of lifelong exercise on antioxidant enzyme activities and fractional synthesis rate of protein (FSRP) were examined at various ages (2-26 mo) in heart, liver, and muscle of mice that had been selectively bred for high wheel-running activity, housed with (S+) or without (S-) a running wheel, and their random-bred controls (C+) housed with running wheels. FSRP decreased with age and increased in muscle of young, but not old, activity-selected mice. Enzyme activity of superoxide dismutase and glutathione peroxidase decreased with age and showed a peak at 10 mo of age in liver. Selection for wheel-running activity did not affect antioxidant enzyme activity. Daily energy expenditure correlated positively with antioxidant levels in liver. This might indicate that oxidative stress (ROS production) increases with metabolic rate, driving upregulation of antioxidant enzymes. Alternatively, the elevated energy expenditure may reflect the energetic cost of elevated protection, consistent with the disposable-soma hypothesis and with other studies showing positive links between energy expenditure and life span. Long-term elevations in voluntary exercise did not result in elevations in antioxidant enzyme activities or protein synthesis rates.

Protective role of Bacopa monniera on morphine induced hepatotoxicity in rats.

The protective effect of Bacopa monniera on morphine induced liver antioxidant levels was studied in rats. Oral administration of alcohol extracts of Bacopa monniera induced a significant hepatoprotective effect. In the morphine treated group, a significant increase of lipid peroxidation and a significant decrease in liver antioxidant enzyme levels were observed. Simultaneous administration of morphine and Bacopa extract prevented these alterations. The results of this study showed that Bacopa monniera alcohol extract exerted a hepatoprotective effect against morphine induced liver toxicity.

Analysis of water-soluble antioxidants by high-pressure liquid chromatography.

The measurement of endogenous substances that function as biological antioxidants is of importance because the values obtained might be an index of future health. We quantified three water-soluble antioxidants by high-pressure liquid chromatography with electrochemical detection (h.p.l.c.-e.c.). Current-voltage relationships made at various settings of the D2 porous graphite electrode help to identify ascorbic acid, glutathione and uric acid. The antioxidants are determined simultaneously and without need for derivatization. The method is seen to be useful for comparison of normal rat liver with liver that had undergone oxidative stress through ischaemia. Antioxidant levels in liver, kidney, pancreas and intestinal mucosa are presented and compared with literature values. Endogenous contents of oxidized forms of ascorbic acid and glutathione become apparent following exposure of tissue samples to a strong reductant such as 2-mercapthoethanol.

Hepatotoxic effects of CCl 4, on English sole ( Parophrys vetulus): Possible indicators of liver dysfunction

1. 1.Selected serum parameters (enzyme activities and triglycerides) and liver glutathione and vitamin C concentrations were measured in English sole ( Parophrys vetulus) after i.p. injection of carbon tetrachloride (CCl 4, a hepatotoxin in fish. 2. 2.Serum lactate dehydrogenase (LDH), alkaline phosphatase (AP) and glutamate dehydrogenase (GDH) activities and the concentration of triglycerides increased in a dose-dependent manner 24 hr post injection. 3. 3.Concentrations of glutathione (reduced and oxidized) and ascorbic acid (vitamin C) in liver did not change in response to CCl 4, toxicity 24 hr post injection. 4. 4.These studies indicate that serum AP activity and triglyceride concentration can be useful in assessing the effects of CCl 4-induced liver toxicity in this species of marine fish. Serum LDH and GDH activity should be used with some caution in assessing liver damage in English sole, as other tissues represent more likely sources for serum activity. 5. 5.The levels of liver antioxidants do not appear to be significantly affected, 24 hr post injection, by this particular hepatotoxin.