RESUMEN
One new and two known dammarane-type saponins were isolated from the leaves of Gynostemma pentaphyllum using various chromatographic methods. Their structures were identified by HR-ESI-MS,~( 1)H-NMR, ~(13)C-NMR, 2 D-NMR spectra as 2α,3β,12β,20,24(S)-tetrahdroxydammar-25-en-3-O-[β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-β-D-xylopyranosyl(1→6)-β-D-glucopyranoside(1, a new compound, namely gypenoside J5) and 2α,3β,12β,20,24(R)-tetrahdroxydammar-25-en-3-O-[β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-β-D-xylopyranosyl(1→6)-β-D-glucopyranoside(2) and 2α,3β,12β,20-tetrahydroxy-25-hydroperoxy-dammar-23-en-3-O-[β-D-glucopyranosyl(1→2)][β-D-glucopyranosyl]-20-O-[β-D-xylopyranosyl(1→6)]-β-D-glucopy-ranoside(3), respectively. Compounds 1 and 2 were a pair of C-24 epimers. All compounds showed weak cytotoxicity agxinst H1299, HepG2, PC-3, SH-SY5 Y cancer cell lines. However, they exerted protective effect against SH-SY5 Y cellular damage induced by H_2O_2 dose-dependently, of which compound 1 displayed the strongest antioxidant effect. The present study suggested that G. pentaphyllum has antioxidative potential and the saponins from G. pentaphyllum are considered as the active compounds with neuroprotecitve effect.
Asunto(s)
Gynostemma , Estructura Molecular , Fármacos Neuroprotectores/farmacología , Saponinas/farmacología , Triterpenos/farmacologíaRESUMEN
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.