RESUMO
Hydrogen peroxide (H2O2) can induce apoptosis by releasing reactive oxygen species (ROS) and reactive nitrogen species, which cause mitochondrial damage. The present study aimed to investigate the protective effects of flavonoids from the leaves of Carya cathayensis Sarg. against H2O2-induced oxidative damage and apoptosis in vitro. The bioactivity of total flavonoids (TFs) and five monomeric flavonoids [cardamonin (Car), pinostrobin chalcone, wogonin, chrysin and pinocembrin] from the leaves of Carya cathayensis Sarg. (LCCS) were tested to prevent oxidative damage to rat aortic endothelial cells (RAECs) induced by H2O2. Oxidated superoxide dismutase, glutathione peroxidase, malondialdehyde, lactate dehydrogenase and ROS were analyzed to evaluate the antioxidant activity. Gene and protein expression patterns were assessed using reverse transcription-quantitative PCR and western blotting, respectively. The results indicated that TFs and Car inhibited H2O2-induced cytotoxicity and apoptosis of RAECs. Additionally, they regulated the level of oxidase and inhibited the production of ROS. Overall, the TFs extracted from LCCS could potentially be developed as effective candidate drugs to prevent oxidative stress in the future; moreover, they could also provide a direction in investigations for preventing antioxidant activity through the ROS pathway.
RESUMO
The main purpose of this study was to evaluate the estrogenic properties of total flavonoids (TFs) and five flavonoid monomers (cardamonin (Car), pinostrobin chalcone (PC), wogonin (Wo), chrysin (Chr) and Pinocembrin (PI)) from leaves of Carya cathayensis Sarg (LCC). TFs from LCC were isolated and determined using HPLC. The 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were performed to assess the effects of flavonoids on cell proliferation and cell cycle, respectively. The molecular docking technique was applied to investigate binding conformations of the monomers from LCC to the estrogen receptor ERα and ERß. Gene and protein expression patterns were assessed using quantitative real-time PCR (qRT-PCR) and western blot, respectively. The results showed that TFs, Car, PC, Wo and Chr promoted proliferation of MCF-7 cells and cell transition from the G1 to S phase, and inhabitation of MCF-7 cell proliferation was observed after the treatment of PI. Molecular docking studies confirmed ERs as molecular targets for the monomers. TFs, Car, PC, Wo and Chr from LCC promoted gene expression of ERα, ERß, progesterone receptor (PR) and pS2. Our collective results demonstrated that TFs and monomers from LCC may exert ER agonist activity through competitively bind to ER, inducing ER upregulation and active ER to estrogen response element (ERE)- independent gene regulation. As an abundant natural product, LCC may provide a novel medicinal source for treatment of diseases caused by estrogen deficiency.