ABSTRACT
Antioxidants help to reduce reactive oxygen species which can be produced in the course of carrying out normal physiologic activities. Naturally occurring antioxidants can be found in medicinal plants and Pentaclethra macrophylla, a leguminous plant of the family Fabaceae is one of such medicinal plants.The aim of this study is to evaluate the antioxidant activity of Methanol stem bark extract and fractions of Pentaclethra macrophylla.
The powdered sample (1Kg) was extracted using maceration technique with methanol as a solvent. The sample was allowed to macerate for 72 hours after which the filtrate from the mixture was concentrated using a rotary evaporator and the extract yield was calculated. The extract was fractionated into N-Hexane, Dichloromethane, ethyl acetate and aqueous methanol fractions. Each fraction and the crude sample were tested to determine the total phenol content and total flavonoid content. The antioxidant activity of the extract and fractions was determined using DPPH radical scavenging assay method.
The phytochemical screening of the stem bark showed the presence of carbohydrates, reducing sugars, flavonoids, terpenoids and phenolic compounds. Tannins, anthraquinone and alkaloids were absent. The percentage yield of the sample obtained is 16.142%. From the IC50, the crude sample and the DCM, Ethyl acetate and aqueous methanol fractions exhibited antioxidants stronger than that of Ascorbic acid. The aqueous methanol fraction had the highest antioxidant activity, a total phenol content of 132.36±4.03mg GAE/g and a total flavonoid content of 31.50±3.47 mg QE/g. This study has shown that the stem bark of P. macrophylla has excellent antioxidant properties in different solvent fractions.
