Desmodinosides A-E: New Flavonoid C-Glycosides from Desmodium Heterocarpon VAR. Stigosum with Hepatoprotective and Antifungal Activity

Abstract

Five new flavonoid C-glycosides named desmodinosides A-E (1-5) and one known compound, apigenin 6-C-β-D-xylopyranosyl-2ʹʹ-O-β-D-glucopyranoside (6) have been isolated from the methanol extract of the aerial parts of Desmodium heterocarpon var. stigosum. These compounds were determined by 1D and 2D-NMR and HR-MS spectroscopies. In particular, the methanol extract of this plant possessed both potent hepatoprotection and antifungal inhibition. This extract caused a high hepatoprotection with an IC50 of 43.07 µg/mL. The hepatoprotective effect on human liver hepatoma cells (HepG2) of the isolated flavonoid C-glycosides 1–6 was observed. Desmodinosides A-C (1-3) were found to excert moderate hepatoprotective activity on HepG2 cells. Of these, compound 2 showed the best hepatoprotective activity with an IC50 value of 74.12 µg/mL. Besides, this extract effectively inhibited the growth of oomycete Phytophthora infestans with IC50 of 13.3 µg/mL and IC90 of 78.7 µg/mL. Compounds 5 and 6 were determined to correspond for the oomycete inhibition; they strongly inhibited P. infestans with IC50 values of 27.4 and 24.7 µg/mL, respectively. Our study demonstrated for the first time the new flavonoid C-glycosides from D. heterocarpon var. stigosum and their novel pharmacological properties. The study findings also suggest the plant extract and its metabolites could be used as a new botanical source of bioactive compounds.

Keywords: Desmodium heterocarpon var. stigosum, flavonoid C-glycoside, hepatoprotective activity, antifungal activity