Dietary polyphenols modulate starch digestion and glycaemic level: a review

Abstract

Polyphenols, as one group of secondary metabolite, are widely distributed in plants and have been reported to show various bioactivities in recent year. Starch digestion not only is related with food industrial applications such as brewing but also plays an important role in postprandial blood glucose level, and therefore insulin resistance. Many studies have shown that dietary phenolic extracts and pure polyphenols can retard starch digestion in vitro, and the retarding effect depends on the phenolic composition and molecular structure. Besides, dietary polyphenols have also been reported to alleviate elevation of blood glucose level after meal, indicating the inhibition of starch digestion in vivo. This review aims to analyze how dietary polyphenols affect starch digestion both in vitro and in vivo. We can conclude that the retarded starch digestion in vitro by polyphenols results from inhibition of key digestive enzymes, including α-amylase and α-glucosidase, as well as from interactions between polyphenols and starch. The alleviation of postprandial hyperglycemia by polyphenols might be caused by both the inhibited starch digestion in vivo and the influenced glucose transport. Therefore, phenolic extracts or pure polyphenols may be alternatives for preventing and treating type II diabetes disease.

Keywords:

• Dietary polyphenols
• α-Amylase
• α-Glucosidase
• Starch digestion
• Binding interactions
• Glycaemic control

Acknowledgments

The research was financially supported by the National Key R&D Program of China (2017YFC1601002, 2017YFD0400405), the National first-class discipline program of Food Science and Technology (JUFSTR20180203) the Science & Technology Pillar Program of Jiangsu Province (BE2018304, BE2016711).