Novel terpenoid-type quinones isolated from Pycnanthus angolensis of potential utility in the treatment of type 2 diabetes

Using an ethnomedical-based drug discovery program, two previously unknown compounds (SP-18904 and SP-18905) from Pycnanthus angolensis were isolated that lower glucose concentrations in mouse models of type 2 diabetes. SP-18 904 and SP-18905 are terpenoid-type quinones that significantly lowered pla sma glucose concentration (p < .05) when given orally to either ob/ob or db /db mice, both of which are hyperglycemic and hyperinsulinemic. The antihyp erglycemic actions of SP-18904 and SP-18905 were associated with significan t decreases in plasma insulin concentrations (p < .05), suggesting that bot h compounds lowered glucose by enhancing insulin-mediated glucose uptake. T his was supported by the insulin suppression test in ob/ob mice. Studies in hyperglycemic, insulin-deficient mice and in vitro experiments on 3T3-L1 a dipocytes further supported this conclusion. As such, these two terpenoid-t ype quinones represent a new class of compounds of potential use in the tre atment of type 2 diabetes.