Comparative hypoglycemic activities of aqueous and ethanolic extracts of four medicinal plants (Acanthus montanus, Asystasia gangetica, Emilia coccinea and Hibiscus rosasinensis) in Type I diabetic rats

BACKGROUND The present study ascertained the capacities of crude aqueous and ethanolic leaf extracts of Acanthus montanus (ACMO), Asystasia gangetica (ASGA), Emilia coccinea (EMCO), and Hibiscus rosasinensis (HIRO), as well as their combinatorial formulations to ameliorate hyperglycemia in Type I diabetic rats. MATERIALS AND METHODS Hyperglycemia was induced by single intraperitoneal injection of alloxan monohydrate in phosphate buffer saline (PBS) solution (pH = 7.4) dosage = 120 mg/kg; bw. Individual hyperglycemic rats (HyGR) received separate doses of either 20 mg/kg bw/24 h of ACMO, ASGA, EMCO or HIRO, as well as their combinatorial formulations (AAEH) for 14 days. Preparation of aqueous extracts (AQx) and ethanolic extracts (ETHx) of the four herbal samples was according to standard methods. Blood samples were drawn from 12 h post-fasted rats at regular intervals of 24 h for 14 days and measured for fasting blood glucose concentration (FBGC) using the glucose oxidase spectrophotometric method. RESULTS Cumulatively, ETHx of the herbal samples exhibited the greater capacity to lower FBGC in HyGR than that of the AQx. ETHx of AAEH exhibited the highest capacity to lower FBGC in HyGR by 53.55 ± 1.04%, whereas AQx of EMCO exhibited the lowest capacity to lower FBGC, which corresponded to 36.19 ± 0.88%. CONCLUSION The study showed that ETHx of the herbal samples were comparatively more potent than the corresponding AQx as agents of glycemic control and for the management of hyperglycemia. Furthermore, the combination of the herbal extracts synergistically improved the therapeutic potentials of the individual herbal extracts.