Phytochemistry and Antioxidants Activities of Four Different Solvent Extracts of Justicia secunda Stem.

This study was aimed to evaluate phytochemical and antioxidant activities of Justicia secunda stem crude extracts from four different solvents in increasing polarities, with the idea of isolating some of the metabolites (secondary). In order to ensure that a wide range of polarities of the compound could be extracted, the method of cold maceration was used in the extraction by serial exhaustive extraction method which involves successive extraction with solvents of increasing polarity from a non-polar (hexane) to a more polar solvent (methanol). The crude extracts were concentrated using rotary evaporator at 400C; it was observed that methanol extract had the highest yield (4.13 %); followed by acetone (2.40 %); ethyl acetate (1.65 %) and hexane had the least yield (1.03 %). Phytochemical screening of the crude extracts showed the presence of alkaloids, flavonoids, terpenoids, tannins, phenol, steroids cardiac glycoside and phlobatannins The antioxidant activity of the crude extracts were determined using DPPH (1,1-diphenyl-2-picryl hydrazyl) free radical scavenging assay at various concentrations of 0.0313, 0.0625, 0.1250, 0.2500, and 0.500mg/mL, with vitamin C as standard. The IC50 values were calculated and observed that the standard had the least IC50 value of 22.762 mg/mL indicating highest scavenging ability, comparing to that of the extracts, methanol extract (48.04 mg/mL) was closely comparable to that of the standard, closely followed by that of acetone extract (53.71 mg/mL), then ethyl acetate (66.03 mg/mL), and lastly hexane (74.62 mg/mL).