Xiaoke, a traditional Chinese treatment for diabetes. Studies in streptozotocin diabetic mice and spontaneously diabetic BB/E rats.

Xiaoke tea is consumed as a traditional herbal treatment for diabetes mellitus in China. An aqueous extract of Xiaoke (1 g of dried plant preparation in 64 ml of water), supplied ad lib in place of drinking water during the induction and development of streptozotocin diabetes in mice, reduced (about 30%) plasma glucose concentrations by 25 days. The polydipsia and hyperphagia of the streptozotocin diabetic mice were also reduced by Xiaoke, and the effects lapsed after treatment was withdrawn. Xiaoke did not significantly alter plasma insulin concentrations. Consumption of the Xiaoke extract by insulin-treated diabetic BB/E Wistar rats did not affect glycaemic control or body wt. When insulin treatment was reduced and discontinued, Xiaoke failed to prevent the progression of severe hyperglycaemia and weight loss. The results suggest that the slowly generated antihyperglycaemic effect of Xiaoke in streptozotocin diabetic mice may involve an extrapancreatic effect on food intake, glucose production or glucose clearance. However, as evidenced in BB/E rats, Xiaoke does not substitute for insulin in the absence of endogenous insulin secretion.