Vol. 4, Issue 4 (2019)
Phytochemical Characterization and Antioxidative Property of Ocimum canum Sims.
Author(s): R Kuralarasi, S Revathilakshmi
Abstract: Medicinal plants are the richest bio-resource of drugs for traditional systems of medicine, modern medicine, nutraceuticals, food supplements, folk medicines, pharmaceutical intermediates and chemical entities for synthetic drugs. In the present study aimed to find out the phytochemicals present in the various solvent leaf extracts of Ocimum canum Sims and all the fractions of O. canum demonstrated H-donor activity. The highest DPPH radical scavenging activity was detected in chloroform fraction (IC50 0.145 mg/ml), followed by ethyl acetate, pet-ether and residual fractions (IC50 0.164, 0.29 and 0.6 mg/ml respectively). The residual fraction of O. canum showed the highest reducing ability (absorbance 0.620) than all the other fractions tested. The scavenging activity of the pet-ether fraction (IC50 0.141mg/ml) was higher than that of quercetin (0.308 mg/ml). The residual, chloroform and ethyl acetate fractions also showed significant scavenging activities (IC50 of RF, CF and EAF were 0.125, 0.186 and 0.232 mg/ml respectively) when compared to the standard. The chloroform fraction showed strong nitric oxide scavenging activity (IC50 0.183 mg/ml) and that of standard curcumin was 0.078 mg/ml. The total antioxidant activity of the fractions of O. canum was determined by the thiocyanate method and compared with the standard, a-tocopherol. The phosphomolybdate method is quantitative, since the total antioxidant capacity is expressed as α-tocopherol equivalents. Among the fractions tested, the chloroform fraction showed the highest ferrous ion chelating ability (IC50 0.276 mg/ml). Moreover, total phenolics concentration equivalents to gallic acid was found in the range of 59.50 to 109.0 mg/g of plant extracts, which correlated with antioxidant activity. The findings indicated promising antioxidant activity of crude extracts of the above plants and needs further exploration for their effective use in both modern and traditional system of medicines.