(-) Epicatechin, a major polyphenolic component of green tea is reported to have insulin mimetic action with protective effects on erythrocytes in a manner similar to insulin. (-) epicatechin also offers antioxidant protection against lipid peroxidation and inhibits platelet aggregation. (-) Epicatechin effects would be beneficial in supporting the management of secondary complications of diabetes. Polyphenols were shown to be useful in the long term preservation of rat pancreatic islets in vitro under physiological conditions. The islets showed significant enhancement of insulin secretion on the 40th day.

Mechanism of action

• Epicatechin is reported to have insulin mimetic action with protective effects on erythrocytes in a manner similar to insulin.

• Epicatechin was shown to mimic the effects of insulin in restoring the acetylcholineesterase activity to normal levels in diabetic erythrocytes.

• Antioxidant protection against lipid peroxidation (hepatic microsomal phospholipase A2 activities and changes of hepatic phospholipid species in streptozotocin-induced diabetic rats). Similar effects also resulted in the inhibition of platelet aggregation.

• Polyphenols were shown to be useful in the long term preservation of rat pancreatic islets in vitro under physiological conditions. The islets showed significant enhancement of insulin secretion on the 40th day.

• Catechins are also reported to inhibit alpha-amylase, thereby preventing the digestion and absorption of carbohydrates that would otherwise contribute to increased blood sugar levels.

• The detailed mechanism of action in blood sugar normalization has as yet to be elucidated.