TOTAL PHENOLIC AND FLAVONOID CONTENTS AND ANTIOXIDANT ACTIVITIES OF LEAF EXTRACTS OF ICACINA TRICHANTHA OLIV.
This study profiles some phytochemicals and the antioxidant effects of the extracts of the leaves of Icacina trichantha. Dried pulverized leaves of I. trichantha were extracted with distilled water before successive partitioning with n-hexane, chloroform and ethyl acetate respectively. Qualitative tests were conducted for
presence of secondary metabolites in the extracts while spectrophotometric method was used to estimate the total contents phenolic and flavonoid contents in each sample. Antioxidant activity was based on 1,1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging activity in vitro assay. Phenolics and flavonoids were detected in all samples, though the amounts were significantly higher (P<0.05)in the ethyl acetate (113.55±1.90 mg GAE/g extract) and n-hexane (19.50±1.50 mg QE/g extract)fractions respectively. There was no significant difference (P>0.05) in the amounts of both metabolites contained in the crude aqueous extract. Ethyl acetate fraction had the most DPPH free radical scavenging activity, which was also indicated from the least IC50 value (58.26 ?g/ml). It compared favourably to the standard, ascorbic acid (66.55 ?g/ml). Higher IC50 values, 118.47 ?g/ml and 868.45 ?g/ml, were obtained in the crude aqueous extract and n-hexane fraction respectively. The study revealed that extract fractions with significantly higher (P<0.05) proportions of phenolics to flavonoids demonstrated higher free radical scavenging activity respectively. The possibility of antagonistic interactions between the flavonoids and phenolics on free radical scavenging capacity of the extracts of this plant species is also suspected.