IN VITRO ANTIOXIDANT ACTIVITY OF ALCOHOLIC EXTRACTS OF WRIGHTIA TOMENTOSA

Summary The objective of the present investigation is to assess the most potent antioxidant alcoholic extract from the leaf & bark of Wrightia tomentosa. The invitro-methods used to predict the antioxidant effect were DPPH radical scavenging assay, reducing power ability, Phospho molybdate method & the estimation of total phenolic and flavanoid contents using pyrocatechol & quercetin as standards. The % scavenging activity at different concentrations was determined and the IC 50 value of the extracts was compared with that of standard, ascorbic acid. The ethanolic bark extract gave an IC 50 value of 75.0 µg/ml when compared with leaf extract (IC 50 = 135.1 µg/ml). The reducing power was investigated by Fe 3+ _ Fe 2+ transformation in the presence of extracts tested using Butylated hydroxy toluene as standard. The ethanol bark extract showed the highest reducing ability having an absorbance of 0.690 using 800µg/ml concentration at 700nm. The total antioxidant capacity by phospho molybdate method is expressed as α- tocopherol equivalents. Among the extracts tested, the ethanol bark extract contains 8.3 µg Vitamin E equivalent/ mg, which has apparently twice greater antioxidant capacity than the leaf extract (4.2 µg Vitamin E equivalent/mg). The content of total phenolics (9.1 µg Pyrocateechol equivalent/mg) and total flavanoids (20.0 µg Quercetin equivalent/mg) in the ethanol bark extract was considerably higher than the leaf extract. Based on the above results, the higher the flavanoid content, the higher the antioxidant capacity was very well observed with ethanolic bark extract. Hence the alcoholic extract of Wrightia tomentosa dried bark could be considered for preparation of nutraceuticals with potent antioxidant effect suitable for prevention of human disease.