Gynura medica leaf extract contains significant amounts of flavonols and phenolic acids and exhibits powerful hypoglycemic activity against diabetic rats
in vivo. However, the hypoglycemic active constituents that exist in the plant have not been fully elaborated. The purpose of this study
[...] Read more.
Gynura medica leaf extract contains significant amounts of flavonols and phenolic acids and exhibits powerful hypoglycemic activity against diabetic rats
in vivo. However, the hypoglycemic active constituents that exist in the plant have not been fully elaborated. The purpose of this study is to isolate and elaborate the hypoglycemic activity compounds against inhibition the yeast α-glucosidase
in vitro. Seven phenolic compounds including five flavonols and two phenolic acids were isolated from the leaf of
G. medica. Their structures were identified by the extensive NMR and mass spectral analyses as: kaempferol (
1), quercetin (
2), kaempferol-3-
O-β-D-glucopyranoside (
3), kaempferol-3-
O-rutinoside (
4), rutin (
5), chlorogenic acid (
6) and 3,5-dicaffeoylquinic acid methyl ester (
7). All of the compounds except
1 and
3 were isolated for the first time from
G. medica. Compounds
1–
7 were also assayed for their hypoglycemic activity against yeast α-glucosidase
in vitro. All of the compounds except
1 and
6 showed good yeast α-glucosidase inhibitory activity with the IC
50 values of 1.67 mg/mL, 1.46 mg/mL, 0.38 mg/mL, 0.10 mg/mL and 0.53 mg/mL, respectively.
Full article
