INHIBITION OF LIPID-PEROXIDATION AND SUPEROXIDE GENERATION BY DITERPENOIDS FROM ROSMARINUS-OFFICINALIS

Four diterpenoids, carnosic acid (1), carnosol (2), rosmanol (3), and epirosmanol (4), were isolated as antioxidative agents from the leaves of Rosmarinus officinalis by bioassay-directed fractionation. These diterpenoids inhibited superoxide anion production in the xanthine/xanthine oxidase system. Mitochondrial and microsomal lipid peroxidation induced by NADH or NADPH oxidation were also completely inhibited by these diterpenes at the concentration of 3-30 mu M. Furthermore, carnosic acid protected red cells against oxidative hemolysis. These phenolic diterpenes were shown to be effective to protect biological systems against oxidative stresses.