EXTRACTION OF URSOLIC ACID FROM OCIMUM SANCTUM: MODULATORY EFFECT OF URSOLIC ACID ON HYDROGEN PEROXIDE INDUCED DNA DAMAGE IN HUMAN LYMPHOCYTES

The objective of the present study was to i) Extract ursolic acid , a pentacyclic triterpenoid from Ocimum sanctum; ii) develop a HPTLC based method for its quantification; and iii) investigate ursolic acid dependent adaptive response to cytotoxic effect of hydrogen peroxide. To elucidate the possible underlying mechanism(s), lymphocytes were co-incubated with hydrogen peroxide (0, 10, 25 and 100 mM) and ursolic acid (20 and 40 mg/ml incubation medium). After 2 h of incubation we investigated the profile of DNA strand breaks, intracellular reactive oxygen species (ROS), apurinic/apyrimidinic sites (AP sites) and 8-hydroxy-2′-deoxyguanosine (8-OH-dG) residues in DNA. Results showed that ursolic acid inhibited hydrogen peroxide induced DNA strand breaks. Ursolic also showed significant free radical scavenging as indicated by reduced ROS and decreased AP sites. The formation of 8-hydroxy-2′-deoxyguanosine (8-OH-dG) in lymphocyte DNA was also inhibited. These findings clearly showed mechanistic basis for protective effect of ursolic acid against intracellular ROS and consequent generation of AP sites in genomic DNA.  In conclusion, our studies clearly suggest that ursolic acid might be a possible chemo-preventive phytochemical against oxidative stress.