Four
flavonoids were isolated from
Gynostemma pentaphyllum by
chromatography methods and their structures were identified by MS and NMR spectra data as
quercetin-3-O-( 2″,6″-di-α-L-rhamnosyl)-β-D-
galactopyranoside( 1),
quercetin-3-O-( 2″,6″-di-α-L-rhamnosyl)-β-D-glucopyranoside( 2),
quercetin-3-O-( 2″-α-L-rhamnosyl)-β-D-
galactopyranoside( 3),and
quercetin-3-O-( 2″-α-L-rhamnosyl)-β-D-glucopyranoside( 4). Among them,compounds 1-3 were obtained from the
Cucurbitaceae family for the first
time.The four
flavonoids showed potent
antioxidant effects against the DPPH,·OH and ■radicals
in vitro,especially for DPPH radical scavenging activity with the
IC50 values of 71. 4,29. 5,48. 3 and 79. 2 μmol·L~(-1),respectively. Moreover,the four
flavonoids displayed strong
cytoprotection against AAPH-induced
oxidative damage in
LLC-PK1 cells by suppressing the increase of
malondialdehyde( MDA) and the decrease of the
superoxide dismutase( SOD) and
glutathione( GSH). Since further
research is needed to prove its
efficacy in vivo and
clinical trial,the study may provide four potential
antioxidants from G. pentaphyllum.