Effect of (-)epicatechin on cAMP content, insulin release and conversion of proinsulin to insulin in immature and mature rat islets in vitro.

(-)Epicatechin, an active principle in the water extract of the bark of Pterocarpus marsupium increases the cAMP content of the islets which is associated with the increased insulin release, conversion of proinsulin to insulin and cathepsin B activity. The response of the islets to the (-)epicatechin stimulation is more pronounced in immature (one month old) than in mature (12 month old) rats.