Original Articles: 2011 Vol: 3 Issue: 1
Phytochemical Investigation of methanolic fractions of Acalypha ornata (Hochst) leaves for antioxidant and toxicity activities
Secondary metabolites of medicinal importance phenolics, resins, flavonoids, steroids, tannins and carbohydrates were obtained in the crude methanolic extract of Acalypha ornata (Hoscht). The methanolic extract was separated into 262 fractions by using a mixture of hexane, ethylacetate and methanol and silica gel 70-230 mesh as adsorbent in a gradient elution - column chromatographic technique. The bulked fractions were subjected to antioxidant screening and brine shrimp lethality assay. The activity of the fractions was compared with three antioxidant agents; ascorbic acid, butylatedhydroxyanisole (BHA) and a-tocopherol. Samples W4, W5, W6, W7 and W10 possessed high percentage inhibition than vitamin C at 1.0 to 0.0625 mg/ml. BHA showed a generally high percentage inhibition than all test samples at 1.0 and 0.5 mg/ml while fractions W4, W5 and W6 possessed weak free radical scavenging activity. The better scavenging activity of A. ornata could be linked to the presence of secondary plant products like flavonoids and phenols which have ability to scavenge hydroxyl radicals, superoxide anions and lipid peroxy radicals. Brine shrimp lethality test showed that fractions W10, W16 and W17 were not toxic as the LC50 (mg/ml) values were greater than 1000 mg/ml at 95% confidence level.