Assessment of shelf-life of extract through WHO recommended stability study involving chromatographic and biological activity analyses.

Stability study on extract under WHO recommended accelerated and long-term conditions for 6 and 30 months, respectively was carried out by taking gymnemagenin as a marker and by evaluating antidiabetic activity through different models. Gymnemagenin was not detected in any stability sample indicating that gymnemic acids (GAs) remain stable in the extract under the test conditions. The extract and its GA rich fraction exhibited mild α-glucosidase inhibitory activity (18-27%) that remained same during the study. Neither hypoglycemic nor anti-hyperglycemic effect was induced by the extract in normal rats in oral glucose tolerance test. The extract and GA rich fraction showed significant antidiabetic activity in alloxan-induced diabetic rats that remained same in all stability samples. Based on these findings, a shelf-life of at least 30 months is suggested for extract under long-term conditions, and gymnemagenin as a marker for shelf-life assessment of products derived from the plant.