ANTIOXIDATIVE ACTION OF DITERPENOIDS FROM PODOCARPUS-NAGI

Diterpenoids, totarol (1), totaradiol (2), 19-hydroxytotarol (3), tota ral (4), 4 beta-carboxy-19-nortotarol (5), sugiol (6), isolated from P odocarpus nagi, were evaluated as antioxidants. Microsomal lipid perox idation induced by Fe(III)-ADP/NADPH and mitochondrial lipid peroxidat ion induced by Fe(III)-ADP/NADH were inhibited by these terpenoids. Th ey inhibited linoleic acid autoxidation but not generation of superoxi de anion. Totarol (1) protected mitochondrial respiratory enzyme activ ities against NADPH induced oxidative injury. Totarane diterpenes from P. nagi were shown to be effective to protect biological systems and function against various oxidative stresses.