New Halogenated Flavonoids from <i>Adenosma bracteosum</i> and <i>Vitex negundo</i> and Their α‐Glucosidase Inhibition
Ngoc‐Hong Nguyen, Thuc‐Huy Duong, Huy Truong Nguyen, Y. Thien Vu, Thi‐Minh‐Dinh Tran, Thi‐Thanh‐Van Ho, Chi‐Cong Mai, Dinh‐Tri Mai, Hoang‐Chuong Nguyen, Huong Thuy Le, Duc‐Dung Pham
Abstract
Abstract Adenosma bracteosum and Vitex negundo are natural sources of methoxylated flavonoids. Little is known about the α‐glucosidase inhibition of multi‐methoxylated flavonoid derivatives. Eighteen natural flavonoids were isolated from A. bracteosum and V. negundo . Seven halogenated derivatives were synthesized. Their chemical structures were elucidated by extensive NMR analysis and high‐resolution mass spectroscopy as well as comparisons in literature. All compounds were evaluated for their α‐glucosidase inhibition. Most compounds showed good activity with IC 50 values ranging from 16.7 to 421.8 μM. 6,8‐Dibromocatechin was the most active compound with an IC 50 value of 16.7 μM. A molecular docking study was conducted, indicating that those compounds are potent α‐glucosidase inhibitors.