Oxidative Stress and Salvia miltiorrhiza in Aging-Associated Cardiovascular Diseases

Figure 1

Vascular reactive oxygen species production. Oxidases convert oxygen to superoxide, which is then dismutated to H₂O₂ by superoxide dismutase (SOD). H₂O₂ can be converted to H₂O by catalase or glutathione peroxidase. In addition, coupled endothelial NO synthase (eNOS) catalyzes the formation of nitric oxide (NO). When tetrahydrobiopterin (BH4) generation is reduced, the uncoupled eNOS produces superoxide instead of NO. The superoxide can react rapidly with NO to form peroxynitrite (ONOO^-), a powerful oxidant and nitrating agent. Reference numbers are inside the parentheses. DLA: 3,4-dihydroxyphenyl lactic acid; SM: Salvia miltiorrhiza; Sal A: salvianolic acid A; Sal B: salvianolic acid B; Tan IIA: tanshinone IIA.