Two new flavonoid-triterpene saponin meroterpenoids from Clinopodium chinense and their protective effects against anoxia/reoxygenation-induced apoptosis in H9c2 cells.

Two new flavonoid-triterpene saponin meroterpenoids, clinoposides G (1) and H (2) were isolated from the aerial parts of Clinopodium chinense (Benth.) O. Kuntze. Their structures were elucidated through spectroscopic and electronic circular dichroism (ECD) analyses. Compounds 1 and 2 were evaluated for their protective effects against anoxia/reoxygenation(A/R)-induced injury in H9c2 cells. A/R treatment severely injured the H9c2 cells, which was accompanied by apoptosis. Both 1 and 2 pretreatment significantly inhibited cell injury and apoptosis, improved mitochondrial membrane potential, increased activities of antioxidant enzymes, and reduced the levels of the inflammatory cytokines. In addition, the presence of 1 and 2 significantly decreased the protein level of p65 and increased the level of Nrf2 in cell nucleus. Unique chemical structure and good biological activity of 1 and 2 elucidated the potential of meroterpenoids as a promising reagent for treating heart disease.