Enhanced anti-diabetic activity of polyphenol-rich de-coumarinated extracts of Cinnamomum cassia

Although the insulin potentiating activity of Cinnamomum cassia extracts has been studied in detail, no systematic investigations have so far been reported to standardize those extracts with respect to their bioactive polyphenol and toxic coumarin contents. Moreover, no process has been reported for the preparation of de-coumarinated water-soluble polyphenol-rich extracts of cinnamomum species. In the present contribution, we describe the preparation of de-coumarinated polyphenol-rich extracts of Cinnamomum cassia containing 45 and 70% gallic acid equivalents of polyphenol content and their characterization by tandem mass spectrometry. These extracts were investigated for their relative anti-hyperglycaemic effects in comparison with a standard aqueous extract containing 18% polyphenol content and 0.8% coumarin. De-coumarinated extracts were found to be safe and showed 3.4 fold enhancements in relative lowering of blood sugar levels as compared to the standard cinnamon extract, when administered to streptozotocin-induced diabetic rats at 200 mg/kg body weight for 30 days.