The invention describes compositions and methods containing nonconventional plant materials, and more particularly the species Flemingia macrophylla and Careya arborea, that help to maintain normal blood sugar levels in humans and animals. The method of preparation of such compositions and methods of quantifying active principles therein are also described. A Metformin-like compound were found to be the active hypoglycemic principle in Flemingia macrophylla and Careya arborea root bark. The compositions of the invention were found to be safe for therapeutic use.