Oral antidiabetic activities of different extracts of Caesalpinia bonducella seed kernels

Caesalpinia bonducella F. (Leguminosae) is a medicinal plant, widely distributed throughout India and the tropical regions of the world. Its seed kernels are used in the management of diabetes mellitus, in the folklore medicine of Andaman and Nicobar as well as the Caribbean Islands. The seed kernel powder was reported to have hypoglycaemic activity in experimental animals. Four extracts (petroleum ether, ether, ethyl acetate and aqueous) of the seed kernels were prepared and tested for their hypoglycaemic potentials in normal as well as alloxan induced diabetic rats. In normal rats, only ethyl acetate and aqueous extracts showed a minimum significant hypoglycaemic effect, compared to that of glibenclamide. In diabetic rats, both the polar extracts (ethyl acetate and aqueous) as well as glibenclamide, showed significant hypoglycaemic effect, besides, reversing the diabetes induced changes in lipid and liver glycogen levels. As far as the non-polar extracts were concerned, the ether extract showed a marginal antidiabetic activity, while the petroleum ether extract failed to show any. Since both the polar extracts were, chemically, found to contain triterpenoidal glycosides, we presume that they might be the active principles contributing to the antidiabetic actions. In in vitro antioxidant studies, the aqueous extract was found to be devoid of any free radical scavenging activity, while the ethyl acetate extract showed a maximum of 49% activity at the end of 1 h. Although the antioxidant potential of ethyl acetate extract may contribute to overcome the diabetes linked oxidative stress, it needs not necessarily contribute to its hypoglycaemic activity.