Hypoglycemic Effects of a Standardized Extract of Salvia miltiorrhiza Roots in Rats

Salvia miltiorrhiza Bunge (Labiatae) is a Chinese medicinal plant, the dried roots of which (known as Dan-Shen) have been used for hundreds of years in the treatment of a series of ailments, including hyperglycemia. This study was designed to evaluate the hypoglycemic effect of a new, standardized extract of S. miltiorrhiza.

S. miltiorrhiza extract (containing 21% total tanshinones and 3.7% tanshinone IIA) was administered acutely and intragastrically at the doses of 0, 50, 100, and 200 mg/kg to male, healthy, fasted Wistar rats 60 min before the intragastric infusion of a bolus of starch (3 g/kg; a semi-naturalistic experimental condition) (Experiment 1) or glucose (2 g/kg) (Experiment 2).

In both experiments, treatment with S. miltiorrhiza extract produced a dose-related decrease in glycemia, evidenced in terms of reduction of peak value and/or area under the curve of the time-course of glycemia. The effect of S. miltiorrhiza extract occurred at doses devoid of any behavioral toxicity in rats.

The results of this study suggest that the hypoglycemic effect of S. miltiorrhiza extract was likely secondary to an action on carbohydrate metabolism. These results are consistent with several preclinical and clinical data and add further support to the hypothesis that S. miltiorrhiza extracts may act as effective anti-hyperglycemic remedies.

Acute treatment with Salvia miltiorrhiza extract reduced the glycemia rise induced by a bolus of starch in ratsAcute treatment with Salvia miltiorrhiza extract reduced the glycemia rise induced by a bolus of glucose in ratsThis effect relates to both glycemia peak value and area under the curve of the time-course of glycemia. Abbreviations used: Intragastric: i.g., Least significant difference: LSD test.