Reverse phase HPLC estimation of antioxidants and antimicrobial activities of Clerodendrum colebrookianum Walp

Abstract

Methanol crude leaf extract and its solvent fraction were used to evaluate the antioxidant activity, total phenolics, total flavonoid and antimicrobial activity. Solvent fractionation was done by liquid-liquid partition with hexane, ethyl acetate, n-butanol and water and get fraction of hexane, ethyl acetate, n-butanol and residual water respectively. Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Reducing power. For antimicrobial activity, samples were tested for its potent antimicrobial activity against gram-positive bacteria such as Bacillus cereus and Staphylococcus aureus, and gram-negative bacteria viz. Escherichia coli, and Pseudomonas aeruginosa. Among the fractions, n-butanol fraction which had the highest polyphenolic content showed an appreciable DPPH radical scavenging activity (EC50 = 43.49 ± 1.95 µg/mL) as compared to the others fractions. The content of gallic acid, rutin, quercetin and kaempferol in extracts were evaluated by high performance liquid chromatography (HPLC) method. Ethyl acetate fraction showed remarkable effect on B. cereus at low concentration MIC, 1.5 mg/ml. Phytochemical screening showed the presence of different types of compound like alkaloids, carbohydrate, phenols and flavonoids and saponin, which might be responsible for antioxidant and antimicrobial activity.