Relationship between antioxidant and antiglycation ability of saponins, polyphenols, and polysaccharides in Chinese herbal medicines used to treat diabetes

Advanced glycation end-products and oxidative stress have been implicated in the pathogenesis of diabetic complications. Both are known to interact with each other. Therefore, natural compounds or extracts that possess both antioxidant and antiglycation activities might have great therapeutic potential for treating diabetic complications. The main purpose of this study was to evaluate the antiglycation and antioxidant properties of aqueous extracts from 22 Chinese herbal medicines (CHMs) that are commonly used to treat diabetes. The total polysaccharide, polyphenol, and saponin contents in the CHM extracts were determined by use of standard methods to establish their contribution to the antioxidant and antiglycation properties. Our results showed that: 1) half CHMs evaluated in this study possessed both high antiglycation and high antioxidant activities, and 2) the total saponin content was the major compound responsible for the antiglycation activity. The total saponin content may also contribute significantly to antioxidant activity. We conclude that the 11 CHMs with both high antiglycation and high antioxidant activities are potential bioactive compounds in the treatment of diabetes.