EFFECT OF NATURAL ANTIOXIDANT TANSHINONE-II-A ON DNA-DAMAGE BY LIPID-PEROXIDATION IN LIVER-CELLS

Tanshinone II-A (TSII-A) isolated from the root of Salvia miltorrhiza Bunge, a traditional medicine in China, is a derivative of phenanthren equinone, which is known to have antioxidant properties, In the presen t study, effects of TSII-A on DNA damage by lipid peroxidation were in vestigated using liver cells, labeled with [H-3] arachidonic acid, in the presence of FeCl2-DTPA. The results show that the nuclear DNA isol ated from treated cells had higher radioactivity compared to controls and the radioactivity increased with longer incubation times. Purified lipid-DNA adducts had a characteristic fluorescent spectra and showed a decrease of hyperchromicity and melting point. TSII-A could inhibit the association of peroxidation products with DNA in liver cells and prevent a decrease in cell viability and in the the activity of O-6-me thylguanine acceptor protein with increasing incubation time. Compared with other antioxidants, TSII-A had a higher inhibitory ratio, which was similar to vitamin E and butylated hydroxy-toluene (BHT), but mark edly stronger than NaN3, mannatol, and superoxide dismutase (SOD). The se data suggest that TSII-A represents a new and effective antioxidant that inhibits the association of lipid peroxidation products with DNA . Its protective effect may be through breaking the chain reactions of peroxidation by scavenging lipid free radicals, thereby decreasing th eir cytotoxicity.