Inhibition of α-glucosidase activity by quercetin

Quercetin is a flavonoid molecule that is known to be in various sources of natural products such as vegetables and fruits. It has been proven that quercetin plays a crucial role in the prevention of colon cancer as well as homeostasis as radical scavenger in human body. It is also well-known that glycosidases, including α-glucosidase, are involved in a variety of degenerative metabolic disorders. In the course of screening useful α-glucosidase inhibitors, we screened out quercetin as a α-glucosidase inhibitor from chemical libraries. Quercetin was shown to be a reversible, slow-binding, and noncompetitive inhibitor of yeast α-glucosidase with a K_i value of 6.3 × 10^-8 M when it was included with an enzyme mixture. Together, these results show that quercetin has potential in treating disorders including diabetes, although the further mechanistic study is needed.