Hepatoprotective activity of Azadirachta indica leaves on paracetamol induced hepatic damage in rats.

Effect of A. indica leaf extract on serum enzyme levels (glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, acid phosphatase and alkaline phosphatase) elevated by paracetamol in rats was studied with a view to observe any possible hepatoprotective effect of this plant. It was interesting to observe that serum enzyme levels were much elevated in paracetamol induced animals than in those receiving a combination of paracetamol and lead extract. It is stipulated that the extract treated group was protected from hepatic cell damage caused by paracetamol induction. The findings were further confirmed by histopathological study of liver.     

Biochemical and histologic presentations of female wistar rats administered with different doses of paracetamol/methionine

This study was carried out to compare the hepatoprotective effect of methionine on paracetamol treated rats at both the peaks of toxicity and absorption. Female Wistar rats were divided into 17 groups consisting of eight rats per group and treated with different doses of paracetamol/methionine (5:1). Each control rat received 5 ml of physiologic saline. The study was terminated at two different end points -the 4th and 16th hours. Results show that rats administered with toxic doses (1000 mg/kg, 3000 mg/kg, 5000 mg/kg BW) of paracetamol exhibited significant increases in the levels of ALT, AST, γ- GT compared with controls. These increases were much higher at the 16th than 4th hour but serum total protein, albumin and globulin were significantly decreased by the end of the 16th hour. Histology results of rats in the 3000 and 5000 mg/kg (by the end of the 16th hour) confirmed hepatic damage, light microscopic evaluation of liver showed remarkable centrilobular necrosis. Moreover, the presence of mononuclear cells in liver section of rats intoxicated with APAP (5000 mg/kg) suggests a possible involvement of inflammatory process which resulted in regurgitation of bilirubin leading to its elevated level as well as increase activity of ALP. The hepatoprotective effect of methionine, on the other hand, was demonstrated in these rats at the 4th and 16th hours, and both results were comparable and therefore not significantly different but elevation in GGT level still persisted. In conclusion, data obtained from this study suggest that these agents may be capable of inducing GGT, although further study is required to establish a possible relationship between methionine and this enzyme in some other animal species.     

Hepatoprotective activity of Hemidesmus indicus R. br. in rats

Treatment of rats with paracetamol and CCl4 produced a significant increase in the levels of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP), total and direct bilirubin. Rats pretreated with methanolic extract of roots of H. indicus (100-500 mg/kg body weight, po) exhibited rise in the levels of these enzymes but it was significantly less as compared to those treated with paracetamol or CCl4 alone. The results of methanolic extract of H. indicus were comparable with the standard hepatoprotective agent silymarin (100 mg/kg). Maximum hepatoprotective effect was found to be at the dose of 250 mg/kg body weight in case of CCl4 induced hepatic damage while 500 mg/kg body weight in case of paracetamol induced hepatic damage. The results suggest that methanolic extract of H. indicus roots possesses a potential antihepatotoxic activity.     

Hepatoprotective effect of tocopherol against isoniazid and rifampicin induced hepatotoxicity in albino rabbits

Antitubercular drug induced hepatotoxicity is a major hurdle for an effective treatment of tuberculosis. The present study was undertaken to assess the hepatoprotective potential of tocopherol (50 mg/kg and 100 mg/kg, ip) and to compare it with cimetidine (120 mg/kg, ip). Hepatotoxicity was produced by giving isoniazid (INH, 50 mg/kg, po) and rifampicin (RMP, 100 mg/kg, po) combination to albino rabbits for 7 days. Assessment of liver injury was done by estimating levels of alanine transaminase (ALT) and argininosuccinic acid lyase (ASAL) in serum and by histopathological examination of liver. Results revealed that pretreatment with high dose of tocopherol (100 mg/kg) prevented both biochemical as well as histopathological evidence of hepatic damage induced by INH and RMP combination. Moreover, tocopherol (100 mg/kg) was found to be a more effective hepatoprotective agent as compared to cimetidine.     

Studies on the protective effects of caffeic acid and quercetin on chemical-induced hepatotoxicity in rodents.

Caffeic acid and quercetin, the well-known phenolic compounds widely present in the plant kingdom, were investigated for their possible protective effects against paracetamol and CCl4-induced hepatic damage. Paracetamol at the oral dose of 1 g/kg produced 100% mortality in mice while pretreatment of separate groups of animals with caffeic acid (6 mg/kg) and quercetin (10 mg/kg) reduced the death rate to 20% and 30%, respectively. Oral administration of sub-lethal dose of paracetamol (640 mg/kg) produced liver damage in rats as manifested by the significant (P<0.01) rise in serum levels of aminotransferases (aspartate transaminase (AST) and alanine transaminase (ALT)) compared to respective control values. The serum enzyme values were significantly (P<0.01) lowered on pretreatment of rats with either caffeic acid (6 mg/kg) or quercetin (10 mg/kg). Similarly, the hepatotoxic dose of CCl4 (1.5 ml/kg; orally) also raised significantly (P<0.05) the serum AST and ALT levels as compared to control values. The same dose of the caffeic acid and quercetin was able to prevent CCl4-induced rise in serum enzymes. Caffeic acid and quercetin also prevented the CCl4-induced prolongation in pentobarbital sleeping time confirming their hepatoprotectivity. These results indicate that caffeic acid and quercetin exhibited hepatoprotective activity possibly through multiple mechanisms.     

Effect of Azadirachta indica on paracetamol-induced hepatic damage in albino rats.

Azadirachta indica, a plant used widely in Ayurveda, has been reported to have anti-inflammatory, immunomodulatory and adaptogenic properties. The present study evaluates its hepatoprotective role. Fresh juice of tender leaves of Azadirachta indica (200 mg/kg body wt. p.o.) inhibited paracetamol (2 g/kg body wt. p.o.)-induced lipid peroxidation and prevented depletion of sulfhydryl groups in liver cells. There was an increase in serum marker enzymes of hepatic damage (aspartate transaminase, alanine transaminase and alkaline phosphatase) after paracetamol administration. Azadirachta indica pretreatment stabilized the serum levels of these enzymes. Histopathological observations of liver tissues corroborated these findings.     

Protective effect of naringenin on hepatic and renal dysfunction and oxidative stress in arsenic intoxicated rats

Arsenic has a long history as a potent human poison, chronic exposure over a period of time may result in the manifestation of toxicity in practically all systems of the body. In the present investigation the efficacy of naringenin (NRG), a naturally occurring citrus flavanone against arsenic-induced hepatotoxic and nephrotoxic manifestations have been studied in rats. Arsenic trioxide was administered orally at the dose of 2 mg/kg/day with or without combination of NRG (20 or 50 mg/kg/day) for 28 days. At the end of the experimental period the hepatic and renal dysfunction was evaluated by histological examination, serum biomarkers and markers of oxidative stress; lipid peroxidation (LPO), reduced glutathione (GSH) and antioxidant enzymes. Arsenic intoxication increased serum bilirubin, urea, uric acid and creatinine levels, additionally enhanced the activities of hepatic marker enzymes aspartate transaminase, alanine transaminase and alkaline phosphatase. Also, the hepatic and renal tissues showed a marked elevation in LPO levels with a decrease in GSH content and the activities of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase on arsenic treatment. Simultaneous treatment with NRG restored the activities of serum biomarkers and antioxidant enzymes in the tissues in a dose-dependent manner. Furthermore, the histopathological studies confirmed the protective effect of NRG co-treatment by reducing the pathological changes due to arsenic intoxication in both liver and kidney. Thus, our present study demonstrates that NRG has a potential to protect arsenic-induced oxidative hepatic and renal dysfunction.     

Hepatoprotective effect of coumestans isolated from the leaves of Wedelia calendulacea Less. in paracetamol induced liver damage

Effect of coumestans isolated form the leaves of W. calendulacea was evaluated in paracetamol induced liver damage. The increased serum enzyme levels (lactate dehydrogenase, alanine and aspartate transaminase and alkaline phophatase) by paracetamol induction were significantly lowered due to coumestans treatment. Results of this study revealed that coumestans of W. calendulacea afforded a significant protective action in the alleviation of paracetamol induced hepatocellular injury.     

Hepatic polyamines and related enzymes following chlordecone-potentiated carbon tetrachloride toxicity in rats

Chlordecone potentiation of the hepatotoxic and lethal effects of CCL4 has been well established. Recent studies have shown that the suppression of hepatocellular regeneration results in an accelerated progression of liver injury leading to complete hepatic failure. Since polyamines are involved in cell division, these studies were designed to investigate the polyamine levels and associated enzymes in the livers of rats treated with a low-dose combination of CD and CCl4. For comparison, a large toxic dose of CCl4 was also employed. The extent of liver toxicity in rats fed 10 parts per million chlordecone (CD) for 15 days and subsequently injected with a single dose of CCl4 (100 microL/kg body weight) or a high dose of CCL4 alone (2.5 mL/kg body weight) was similar 6 and 24 hr later as assessed by plasma transaminase levels. There was significant elevation in liver ornithine decarboxylase, S-adenosylmethionine decarboxylase, and putrescine at 24 hr and spermidine N1-acetyltransferase, N1-acetylputrescine, putreanine, putrescine, and N1-acetylspermidine at 6 hr in rats treated with the high dose of CCl4 alone compared to the combination treatment. Spermidine levels decreased up to 6 hr and then increased up to 24 hr for both treatments. Spermine continuously decreased up to 24 hr for the CD and CCl4 low-dose combination treatment compared to rats treated with a high dose of CCl4 alone. Spermidine levels were lower than in controls and rose towards control value between 6 and 24 hr after the combination treatment and the high dose of CCl4. Results indicate that the CD and CCl4 low-dose combination treatment increased liver toxicity, resulting in compromised polyamine metabolism that is coincidental with suppressed hepatocellular regeneration, which leads to an accelerated progressive phase of liver injury and culminates in complete hepatic failure.     

Protective role of sinapic acid against arsenic: induced toxicity in rats

Arsenic compounds are classified as toxicants and human carcinogens. Environmental exposure to arsenic imposes a big health issue worldwide. Sinapic acid is a phenylpropanoid compound and is found in various herbal materials and high-bran cereals. It has been reported that sinapic acid has antioxidant efficacy as metal chelators due to the orientation of functional groups. However, it has not yet been examined in experimental animals. In light of this fact, the purpose of this study was to characterize the protective role of sinapic acid against arsenic induced toxicity in rats. Rats were orally treated with arsenic alone (5 mg/kg body weight (bw)/day) plus sinapic acid at different doses (10, 20 and 40 mg/kg bw/day) for 30 days. Hepatotoxicity was measured by the increased activities of serum hepatospecific enzymes namely aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma glutamyl transferase, lactate dehydrogenase and total bilirubin along with increased elevation of lipid peroxidative markers, thiobarbituric acid reactive substances, lipid hydroperoxides, protein carbonyl content and conjugated dienes. The toxic effect of arsenic was also indicated by significantly decreased activities of enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase along with non-enzymatic antioxidant like reduced glutathione. Administration of sinapic acid exhibited significant reversal of arsenic induced toxicity in hepatic tissue. The effect at a dose of 40 mg/kg bw/day was more pronounced than the other two doses (10 and 20 mg/kg bw/day). All these changes were supported by reduction of arsenic concentration and histopathological observations of the liver. These results suggest that sinapic acid has a protective effect over arsenic induced toxicity in rat.     

Influence of small doses of various drug vehicles on acetaminophen-induced liver injury

The biological effects of drug vehicles are often overlooked, often leading to artifacts in acetaminophen-induced liver injury assessment. Therefore, we decided to investigate the effect of dimethylsulfoxide, dimethylformamide, propylene glycol, ethanol, and Tween 20 on acetaminophen-induced liver injury. C57BL/6 male mice received a particular drug vehicle (0.6 or 0.2 mL/kg, i.p.) 30 min before acetaminophen administration (300 mg/kg, i.p.). Control mice received vehicle alone. Liver injury was assessed by measuring the concentration of alanine aminotransferase in plasma and observing histopathological changes. The level of reduced glutathione (GSH) was assessed by measuring total nonprotein hepatic sulfhydrils. Dimethylsulfoxide and dimethylformamide (at both doses) almost completely abolished acetaminophen toxicity. The higher dose of propylene glycol (0.6 mL/kg) was markedly protective, but the lower dose (0.2 mL/kg) was only slightly protective. These solvents also reduced acetaminophen-induced GSH depletion. Dimethylformamide was protective when given 2 h before or 1 h after acetaminophen administration, but was ineffective if given 2.5 h after acetaminophen. Ethanol at the higher dose (0.6 mL/kg) was partially protective, whereas ethanol at the lower dose (0.2 mL/kg) as well as Tween 20 at any dose had no influence. None of the vehicles (0.6 mL/kg) was hepatotoxic per se, and none of them was protective in a model of liver injury caused by D-galactosamine and lipopolysaccharide.     

Relationship between cocaine-induced hepatotoxic neurobehavioral & biochemical changes in mice: the antidotal effects of buprenorphine

Cocaine (COCA)-induced neurobehavioral symptoms, which can be observed simultaneously with exacerbation in biochemical markers, were evaluated in mice, and compared with the changes observed in a representative hepatic failure model induced by thioacetamide (TAA). The effects of pretreatment with buprenorphine (BUP) (0.25, 0.5 or 1 mg/kg i.p.), a mixed opioid agonist-antagonist and an antidote against fatal COCA toxicity, were also examined. At 5 min after the COCA administration (65 mg/kg i.p.), the liver ATP levels were attenuated, and an exacerbation of the CNS-stimulating effects of COCA could be characteristically observed for hepatotoxicity-related neurobehavioral symptoms (changes in alertness, interest, body tension, head movement and walking). At 24 h, the ALT (alanine aminotransferase) activity was elevated, and hepatotoxic attenuation was observed for all of the scores on the neurobehavioral symptoms; this was almost identical to the symptoms observed in the TAA-treated group of mice. Recovery was observed by 72 h for all of the morbid changes. The hepatotoxic biochemical changes and the sum score for all five neurobehavioral symptoms were significantly ameliorated by low doses (0.25 and 0.5 mg/kg) of BUP, both at 5 min and 24 h.     

Intravenous N-acetylcystine: the treatment of choice for paracetamol poisoning.

One hundred cases of severe paracetamol poisoning were treated with intravenous N-acetylcysteine (acetyl-cysteine). There was virtually complete protection against liver damage in 40 patients treated within eight hours after ingestion (mean maximum serum alanine transaminase activity 27 IU/1). Only one out of 62 patients treated within 10 hours developed severe liver damage compared with 33 out of 57 patients (58%) studied retrospectively who received supportive treatment alone. Early treatment and acetylcysteine also prevented renal impairment and death. The critical ingestion-treatment interval for complete protection against severe liver damage was eight hours. Efficacy diminished progressively thereafter, and treatment after 15 hours was completely ineffective. Intravenous acetylcysteine was more effective than cysteamine and methionine and noticeably free of adverse effects. It is the treatment of choice for paracetamol poisoning.     

Modulation of acute cadmium toxicity by Emblica officinalis fruit in rat

The efficacy of Emblica officinalis in modifying the acute cytotoxicity of cadmium in male rats was evaluated. Oral administration of Emblica fruit juice (500 mg/kg, b.w.) for 8 days followed by a single toxic dose of Cd as CdCl2 (3 mg/kg,b.w. ip), considerably reduced the mortality in rats as well as prevented to some extent the cadmium induced histopathological damage in testis, liver and kidneys. Biochemical investigation also revealed reduced levels of Cd induced serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and gamma glutamyltranspeptidase. The enhanced levels of Cd and lipid peroxidation in liver, kidney, and testes and metallothionein and total sulphydryl in liver and kidney by Cd were significantly reduced by Emblica pretreatment. These results suggest cytoprotective potential of Emblica fruit in acute cadmium toxicity which could be due to its multiple role in biological system.     

Serum and liver enzyme changes in rats after short term exposure to dichlorvos

Rat serum and liver ICDH, OCT, GOT and GPT activities are significantly elevated 2-6 hr after i.p. injections of single doses (2.5 mg/kg body wt) of dichlorvos. ICDH, OCT, GOT and GPT activities are significantly increased in serum and liver of rats receiving daily injections (0.25 mg/kg body wt) for 7 days. Although liver SD is significantly elevated in the single and repeated dosage study, serum SD appears unaffected at these levels of dichlorvos toxicity. Changes in serum OCT activity estimations maybe a useful single parameter for screening pesticides for potential hepatotoxic effects in humans and farm animals.     

Methionine and serine synergistically suppress hyperhomocysteinemia induced by choline deficiency, but not by guanidinoacetic acid, in rats fed a low casein diet

The effects of dietary supplementation with 0.5% methionine, 2.5% serine, or both on hyperhomocysteinemia induced by deprivation of dietary choline or by dietary addition of 0.5% guanidinoacetic acid (GAA) were investigated in rats fed a 10% casein diet. Hyperhomocysteinemia induced by choline deprivation was not suppressed by methionine alone and was only partially suppressed by serine alone, whereas it was completely suppressed by a combination of methionine and serine, suggesting a synergistic effect of methionine and serine. Fatty liver was also completely prevented by the combination of methionine and serine. Compared with methionine alone, the combination of methionine and serine decreased hepatic S-adenosylhomocysteine and homocysteine concentrations and increased hepatic betaine and serine concentrations and betaine-homocysteine S-methyltransferase activity. GAA-induced hyperhomocysteinemia was partially suppressed by methionine alone, but no interacting effect of methionine and serine was detected. In contrast, GAA-induced fatty liver was completely prevented by the combination of methionine and serine. These results indicate that a combination of methionine and serine is effective in suppressing both hyperhomocysteinemia and fatty liver induced by choline deprivation, and that methionine alone is effective in suppressing GAA-induced hyperhomocysteinemia partially.     

Experimental analysis of gossypol and chloroquine interaction in serum and in liver of rat.

Interactive effects of gossypol and chloroquine as determined by activities of serum alanine transaminase (ALT), aspartate transaminase (AST) and liver lactate dehydrogenase (LDH), alkaline phosphatase (ALK-pase), glucose-6-phosphatase (G-6-pase) and cholesterol level were investigated in rats. Administration of gossypol for eight weeks, at a concentration of 20 mg per kg body wt. per day with or without chloroquine had no effect on the serum enzymes and glucose-6-phosphatase activities. When chloroquine at a concentration of 5 mg per kg body wt. thrice a week was administered alone, there was a marked decrease in total protein content and ALK-pose activities, while a significant increase in LDH activity was observed. Administration of either gossypol or chloroquine decreased the level of cholesterol. A greater decrease was recorded when both were given together. It is suggested that gossypol can be employed as a male contraceptive among malaria-infected populations.     

Methionine and Serine Synergistically Suppress Hyperhomocysteinemia Induced by Choline Deficiency,but Not by Guanidinoacetic Acid,in Rats Fed a Low Casein Diet

The effects of dietary supplementation with 0.5% methionine, 2.5% serine, or both on hyperhomocysteinemia induced by deprivation of dietary choline or by dietary addition of 0.5% guanidinoacetic acid (GAA) were investigated in rats fed a 10% casein diet. Hyperhomocysteinemia induced by choline deprivation was not suppressed by methionine alone and was only partially suppressed by serine alone, whereas it was completely suppressed by a combination of methionine and serine, suggesting a synergistic effect of methionine and serine. Fatty liver was also completely prevented by the combination of methionine and serine. Compared with methionine alone, the combination of methionine and serine decreased hepatic S-adenosylhomocysteine and homocysteine concentrations and increased hepatic betaine and serine concentrations and betaine-homocysteine S-methyltransferase activity. GAA-induced hyperhomocysteinemia was partially suppressed by methionine alone, but no interacting effect of methionine and serine was detected. In contrast, GAA-induced fatty liver was completely prevented by the combination of methionine and serine. These results indicate that a combination of methionine and serine is effective in suppressing both hyperhomocysteinemia and fatty liver induced by choline deprivation, and that methionine alone is effective in suppressing GAA-induced hyperhomocysteinemia partially.     

Protective effect of hesperidin on nicotine induced toxicity in rats

Nicotine administration (2.5 mg/kg of body weight, sc, 5 days a week for 22 weeks) enhanced lipid peroxidative indices (thiobarbituric acid reactive substances and hydroperoxides) accompanied by a significant increase in the marker enzymes alanine transaminase, aspartate transaminase, alkaline phosphatase and lactate dehydrogenase and elevated levels of cholesterol, triglycerides, phospholipids and free fatty acids in Wistar rats. There was a significant protection by hesperidin administration at different doses (25, 50, 75, 100 and 150 mg/kg body weight) in nicotine-treated rats. However, the effect of hesperidin was more significant at 25mg/kg dose. The results suggest that hesperidin exerts the protective effects by modulating the extent of lipid peroxidation. The results are supported by histopathological observations of lung, liver and kidney.     

Hepatoprotective activity of Psidium guajava Linn. leaf extract

The study was designed to evaluate the hepatoprotective activity of P. guajava in acute experimental liver injury induced by carbon tetrachloride, paracetamol or thioacetamide and chronic liver damage induced by carbon tetrachloride. The effects observed were compared with a known hepatoprotective agent, silymarin. In the acute liver damage induced by different hepatotoxins, P. guajava leaf extracts (250 and 500mg/kg, po) significantly reduced the elevated serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin. The higher dose of the extract (500 mg/kg, po) prevented the increase in liver weight when compared to hepatoxin treated control, while the lower dose was ineffective except in the paracetamol induced liver damage. In the chronic liver injury induced by carbon tetrachloride, the higher dose (500 mg/kg, po) of P. guajava leaf extract was found to be more effective than the lower dose (250 mg/kg, po). Histological examination of the liver tissues supported the hepatoprotection. It is concluded that the aqueous extract of leaves of guava plant possesses good hepatoprotective activity.