Hepatoprotective effect of wax apple (Syzygium samarangense (Blume) cv. Taptimjan) in streptozotocin-induced diabetic rats

Abstract

To investigate the potential effect of wax apple (Syzygium samarangense (Blume) cv. Taaptimjann) to counter diabetes-induced liver damage in male rats.  Diabetic rats were induced using a single intraperitoneal (i.p.) injection of streptozotocin (STZ; 65 mg/kg).  Wax apple at three different doses (50, 100 and 200 mg/kg) was orally administered to diabetic rats for 4 weeks.  Following the dosage program, biochemical parameters, and antioxidant enzyme activities were evaluated.  Expression levels of hepatic ER stress markers, and Bcl-2 member proteins were also determined. The results clearly showed diabetic rats had an increase in blood glucose, and serum liver enzymes aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), along with a decrease in absolute liver weight.  Furthermore, a decrease in antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) activities, reduced anti-apoptotic Bcl-2 protein, increased protein expression of cleaved caspase-3, and GRP78 and CHOP, an ER stress marker, were observed in diabetic liver.  Our study showed that treatment with wax apple dose dependently reduced blood glucose, serum liver enzymes, and protein levels of cleaved caspase-3 and ER stress markers, but improved antioxidant activities, as well as upregulation of anti-apoptotic Bcl-2 protein in the liver of diabetic rats.   These findings suggest that wax apple attenuates STZ-induced diabetic liver damage, possibly through its antioxidant effect and inhibiting ER stress-mediated apoptosis in male rats.