A novel dammarane-type saponin from Gynostemma pentaphyllum and its neuroprotective effect / 中国中药杂志

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.

Effects of flavonoids from Gynostemma pentaphyllum on A549 cells damaged by hydrogen peroxide / 中国中药杂志

This study focuses on the therapeutical effect of flavonoids from Gynostemma pentaphyllum on human lung carcinoma A549 cells induced by H₂O₂ oxidative stress and its possible mechanisms. The oxidative damage model was established using different concentrations H₂O₂ to induce A549 cell for different hours, and then treated with the flavonoids for 10 hours. The effects of flavonoids from G. pentaphyllum on cell viability of A549 cell damaged by H₂O₂ were detected by MTT assay. The contents of ROS were detected by DCFH-DA fluorescent probe method via flow cytometer. The contents of MDA, SOD and GSH were detected by TBA，NBT and DTNB-linked colorimetry assay, respectively. Expressions levels of Nrf2, NQO1 and HO-1 in A549 cells were evaluated by Western blot. The results showed that the cell activity was decreasing with the rise of H₂O₂ concentration within the range of 200-700 μmol·L⁻¹. The cell viability was 60.4% after treated with 500 μmol·L⁻¹H₂O₂ for 10 h, so it was chosen to be as an oxidant stress model. Compared with normal group，the contents of SOD, GSH and HO-1 expressions were lower after damaged with H₂O₂. On the contrary, the contents of ROS and MDA expressions were increased. Compared with model group, the contents of SOD, GSH and the expressions of Nrf2, NQO1 and HO-1 were increased after treated with flavonoids from G. pentaphyllum. The above results demonstrate that flavonoids from G. pentaphyllum may attenuate the effect of H₂O₂-induced oxidative stress on A549 cell by resisting oxidation. The finding may provide a biological evidence for the application of the G. pentaphyllum to fight the oxidative stress related diseases.