ABSTRACT
The antioxidant effects of the triterpenoid-rich extracts from Euryale ferox shell [ES] have been confirmed in vitro. This study examined whether the triterpenoid-rich extract from ES eases human hyperglycemia and diabetes caused by metabolic disorders. Normal and streptozocin [STZ]-induced diabetic mice were used as controls for the four groups that received the triterpenoid-rich extracts of ES suspended in distilled water orally at doses of 200, 300, 400, 500 +/- 2 mg/L. Body weight, blood glucose and pancreatic tissue morphology were observed after 4 weeks. The expression of protein tyrosine phosphatase-1B [PTP1B] and insulin receptor substrate [IRS-1] proteins, which are related to the regulation of glucose metabolism in vivo, were also investigated. Compared with the model group [LD[50] 900 +/- 2 mg/L], it was found that the triterpenoid-rich extracts of ES could regulate glucose metabolism [P<0.01] and cause body weight to return to normal levels [P<0.05]. Islet morphology recovered well, the expression of the negative regulation protein PTP1B gene was reduced and insulin receptor IRS-1 protein expression was increased. These data prove that the triterpenoid-rich extracts from ES have a therapeutic effect on diabetes by insulin resistance