[Show abstract][Hide abstract] ABSTRACT: Medicinal plants have been widely recognized as a renewable resource for the discovery of novel leads and drug. In this study, an approach for screening and identification compounds with cardioprotective activity from medicinal plant extracts by cellular-fluorescence imaging technique was developed. It is a cell-based assay for measuring mitochondrial membrane potential changes in H9c2 cardiac muscle cells exposed to H(2)O(2) by using a fluorescence automatic microscopy screening platform. Rhodamine 123 was used as the fluorescent dye to indicate the change of mitochondrial membrane potential. The sensitivity and linear range of the proposed approach were evaluated and validated using vitamin C, an antioxidative compound. The method was applied to screen active components with potent cardioprotective effects from a traditional Chinese formula. The potential cardioprotective components were identified by liquid chromatography coupled with mass spectrometry (LC/MS). Moreover, the utility of the proposed approach was further validated by three compounds (salvianolic acid B, protocatechuic aldehyde, and tanshinone II A) identified from the formula which showed cardioprotective effects in a dose-dependent manner. These applications suggested that the proposed rapid and sensitive screening approach offers an efficient way to discover active components or compounds from medicinal plants.
[Show abstract][Hide abstract] ABSTRACT: Astragalus membranaceus extract (AME) is a widely used herbal product for the treatment of cardiovascular diseases in China. The present study aimed to evaluate the cardiac protective effects of AME, and to probe the underlying molecular mechanism related to angiogenesis. In this study, AME with 75 microg/mL significantly increased proliferation, migration and tube formation on human umbilical vein endothelial cells (HUVECs). Moreover, in vivo experiments on rats with ligation of left anterior descending artery were performed to study the cardiac protective and angiogenic effect of AME (50 and 100 mg/kg i.g. for 3, 7, 14 days). The results showed that AME inhibited cardiac fibrosis, reduced infarct size, and increased capillary and arteriole densities. Meanwhile, western blot was used to determine protein levels of VEGF, p-AKT, p-GSK3beta and p-mTOR. AME significantly elevated protein expression of VEGF and increased phosphorylation of AKT, GSK3beta and mTOR. In conclusion, AME exerted cardiac protective and angiogenic effects in the ischemic injured heart. The activation of AKT/GSK3beta and AKT/mTOR pathways and elevated expression of VEGF may contribute to the promoted neovascularisation by AME.