Protective effect of α-mangostin derivatives on hypoxia/reoxygenation-induced apoptosis in H9C2 cells and their mechanism

In this study, 17 α-mangostin Boc amino acid/organic acid ester derivatives 1–17 were synthesized and subjected to cytotoxicity and cell viability screening assays. A hypoxia/reoxygenation model of cardiomyocyte injury was selected and compound 5 was found to have a better protective effect against hypoxia/reoxygenation-induced myocardial injury by prophylactic administration screening. The levels of LDH and CK-MB in extracellular fluid were detected by ELISA; apoptosis was detected by Hoechst3358/PI double staining, Annexin V-FITC/PI double staining and mitochondrial membrane potential; the expression of key proteins in PI3K/Akt signaling pathway was detected by western blot. The result showed that compound 5 was non-toxic and has a significant cytoprotection effect at concentrations of 1 μM and 10 μM, and reduced the levels of LDH and CK-MB in the extracellular fluid. Hoechst 33,258/PI double staining results showed that compound 5 treatment significantly reduced bright blue cell nuclei and had anti-apoptotic effects; flow cytometry results showed that compound 5 improved hypoxia/reoxygenation-induced mitochondrial membrane potential and thus apoptosis. The western blot results showed that compound 5 upregulated the levels of p-PI3K and p-Akt, decreased the expression of cleaved caspase-3, cleaved caspase-9 and increased the Bcl-2/Bax ratio in a concentration-dependent manner. In addition, compound 5 reversed the effect of the LY294002 inhibitor. The present study suggests that compound 5 may serve as a potential PI3K activator and a safe and effective lead compound for the treatment of cardiovascular disease.