Chiang Mai Journal of Science

This study aimed to investigate the protective effect of ethanol extract of Hoya kerrii leaf (HKE) on alloxan-induced damage pancreatic cells (RINm5F) and its hypoglycemic activity on alloxaninduced diabetes. In vitro cytoprotective effect was determined on alloxan-induced damage pancreatic cells by using MTT assay. Co-treatment with HKE at 25 μg/mL in alloxan-induced pancreatic cells increased cell viability by approximately 22.38% as compared to alloxan-induced RINm5F group. For in vivo hypoglycemic effects of HKE were evaluated in alloxan-induced diabetic Wistar rats. After 6 h of one-time administration, HKE at a dose level of 600 mg/kg b.w., the level of blood glucose was significantly reduced by approximately 29.67% as compared to diabetic control rats. For continuous intake, HKE succeeded reducing the blood glucose levels until day 11 of post-administration. HKE exhibited hypoglycemic potential by demonstrating percentages of inhibition in blood glucose levels ranging from 9.92-38.55%, as compared to diabetic control rats. HKE also significantly reduced alanine aminotransferase (ALT) and alkaline phosphatase (ALP) levels compared to diabetic control rats but it did not affect to blood urea nitrogen (BUN) and creatinine (Cr) levels in all tested groups. Therefore, HKE supplementation has a protective effect against liver injury caused by alloxan exposure. To evaluate the appropriate safe dose range of HKE in vivo, an acute oral toxicity test was conducted in normal healthy Spraque Dawley rats. HKE is found to be safe up to a dose of 2,000 mg/kg b.w. The results suggest that HKE possesses anti-diabetic activity resulting from its pancreatic cytoprotective and hypoglycemic effects on alloxan-induced diabetes.