title: Phytochemical investigation, cytotoxicity and free radical scavenging activities of non-polar fractions of Acalypha hispida (leaves and twigs).
abstract: Free radicals are involved in the process of lipid peroxidation and play a cardinal role in numerous chronic diseases like cancer, coronary heart disease and ageing. Thus the ability to scavenge free radicals in order to minimize oxidative damage to living cells is very important. The hexane extract ofAcalypha hispida(Burn F.) was screened for phytochemical constituents and was found to contain flavonoids, carbohydrates, phenols and alkaloids. Fractions obtained from chromatographic separation were screened for free radical scavenging activities using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and hydrogen peroxide. Out of the sixteen pooled fractions (S1-S16) screened, compounds S10(91.8 %), S11(93.8 %), S14(92.5 %) and S15(91.4 %) at a concentration of 0.1 mg/ml had significant antioxidant activities when compared to the known antioxidant ascorbic acid (90.9 %). However, in the analysis using hydrogen peroxide, S1(99.5 %), S9(99.2 %), S10(95.4 %),S11(95.8 %) and S15(95.6 %) gave better activity than ascorbic acid (94.8 %), while only S1and S9were more effective than butylated hydroxylanisole (98.9 %) and α-Tocopherol (99.1 %) at the same concentration. The cytotoxicity analysis using the Brine Shrimp lethality test gave LC50values greater than 1000 μg/ml for some of the fractions indicating very low level of toxicity. The better scavenging activity ofA. hispidacould be linked to the presence of secondary plant products like flavonoids and phenols, which have the ability to scavenge hydroxyl radicals, superoxide anions and lipid peroxy radicals.
authors.affiliation: Natural products/Organic Chemistry Unit, Department of Chemistry, University of Ibadan, Nigeria.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Onocha
authors.affiliation: Natural products/Organic Chemistry Unit, Department of Chemistry, University of Ibadan, Nigeria.
authors.forename: G K
authors.initials: GK
authors.lastname: Oloyede
authors.affiliation: Natural products/Organic Chemistry Unit, Department of Chemistry, University of Ibadan, Nigeria.
authors.forename: Q O
authors.initials: QO
authors.lastname: Afolabi
keywords: 2,2-diphenyl-1-picrylhydrazyl radical; Acalypha hispida; cytotoxicity; flavonoids; free-radical; phytochemical constituents