Effects of Kolaviron, a Garcinia Kola biflavonoid, on Rat Intestinal Glucose Absorption and Alpha Amylase Inhibitory Activities.

Abstract

Kolaviron (KV) a biflavonoid from  Garcinia kola seed  has been reported to possess potent hypoglycemic activities. The mechanism of this action is uncertain. In this study, the effects of KV on blood glucose, in-vivo intestinal glucose absorption and alpha amylase activities were investigated. Male albino rats were randomly divided into normal saline treated control (CONT) and two other groups treated with kolaviron at 100 mg/kg (KV100) and 200 mg/kg (KV200). Glucose absorption was studied in vivo from intestinal segment perfused with Kreb's bicarbonate solution containing 5.6 mM glucose. Kolaviron, at doses used, produced significant decreases in blood glucose concentrations 4 hours post-administration, when compared to the control. After 3 hours of administration, KV also decreased arteriovenous difference in glucose concentration by 36.99% and 47.94% in the KV100 and KV200 groups respectively. The jejunal glucose absorption significantly increased (P<0.05) in all the KV treated groups, compared to the control after 40 minutes of infusion. The ileal glucose absorption also increased significantly (P<0.05) after 40 minutes of infusion in all KV treated groups compared to the control. In-vitro, KV (100 – 1000ug/ml) produced a concentration-dependent inhibition of alpha-amylase activity (79.32 ± 0.61% and 24.28 ± 0.73% for the highest concentration and lowest concentrations respectively). KV possibly exerts its reported hypoglycernic effects via the increased glucose extraction by the intestinal cells and by inhibition of activities of α-amylase.