Insulin-secretagogue activity of eleven plant extracts and twelve pure compounds isolated from Aralia taibaiensis.

Aims: To investigate the insulinogenic activities of the eleven saponins enriched traditional Chinese medicine (TCM) extracts.

Main Methods: Radioimmunoassay and trypan blue exclusion assay were used to investigate the insulinogenic activity and cytotoxic effects respectively.

Key Findings: The total saponin extract of Aralia taibaiensis (sAT) exhibited highest insulinogenic activity and no cytotoxicity was recorded. Twelve pure compounds from sAT stimulated insulin secretion from a mouse insulinoma βTC3 cells in a concentration-dependent manner. TA35 outperformed the other compounds which suggested that the active insulinogenic ingredient of sAT was probably TA35. In addition, both sAT and TA35 markedly potentiated glucose-induced insulin secretion.

Significance: Our study is the first to show that sAT dramatically stimulated insulin secretion and its antidiabetic activity may be related to its high saponin content. These findings suggested that sAT and the compound TA35 isolated from sAT may provide novel therapeutic tools for the treatment of non-insulin dependent diabetes mellitus (NIDDM).