RESUMO
The present study was made to investigate the protective effect of methanolic extract of Annona squamosa on isoniazid-rifampicin-induced hepatotoxicity in rats. Rats were divided into five different groups (n=6), group 1 served as a control, Group 2 received isoniazid (100 mg/kg, i.p.) and co-administered with rifampicin (100 mg/kg, i.p.), in sterile water, group 3 and 4 served as extract treatment groups and received 250 & 500 mg/kg bw, p.o methanolic extract of Annona squamosa and group 5 served as standard group and received silymarin 2.5 mg/kg bw, p.o. All the treatment protocols followed 21 days and after rats were sacrificed blood and liver were used for biochemical and histological studies, respectively. Administration of isoniazid and rifampicin caused a significant elevation in the levels of liver marker enzymes and thiobarbituric acid reactive substances (TBARS, oxidative stress markers) in experimental rats. Administration of methanolic extracts of Annona squamosa significantly prevented isoniazid-rifampicin-induced elevation in the levels of serum diagnostic liver marker enzymes (alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP) and gamma glutamate transpeptidase (γ-GT)), serum bilirubin, and TBARS level in experimental groups of rats. Moreover, total protein and reduced glutathione (GSH) levels were significantly increased in treatment group. The effect of extract was compared with a standard drug, silymarin. The changes in biochemical parameters were supported by histological profile. It is to be concluded that the methanolic extract of Annona squamosa protects against isoniazid and rifampicin-induced oxidative liver injury in rats.