Cinnamic acid as one of the antidiabetic active principle(s) from the seeds of Syzygium alternifolium

The Indian traditional system of medicine prescribed plant therapies for diseases including diabetes mellitus. One such plant is Syzygium alternifolium (SA). We reported earlier, that fraction C from aqueous extract of SA seeds showed good antihyperglycemic and antihyperlipidemic activities. In continuation to it, we have performed bioassay guided fractionation of fraction C and identified cinnamic acid as a component with antihyperglycemic activity. A detailed study was undertaken to elucidate its mode of antidiabetic action by giving fraction C (50 mg/kg b.w) orally, once a day for 30 days in STZ induced diabetic rats. The altered enzyme activities of carbohydrate metabolism in liver and kidney of diabetic rats were significantly (p < 0.01) reverted to near normal levels by the administration of fraction C. Fraction C lowered blood glucose as expected, immediately following treatment, and led to glibenclamide-like modulatory effects on enzyme activities related to glucose homeostasis after 30 days treatment, indicating that cinnamic acid may prove useful in diabetes management.