Phytochemical screening and in-vitro antibacterial and DPPH free radical scavenging activities of methanol extract of root of Combretum album Pers.

Abstract

The objective of the study was to investigate in-vitro antibacterial and antioxidant activities of methanolic extract of Combretum album Pers. root. In brief antibacterial efficacies of methanol extract and its petroleum ether fraction (MePET), chloroform fraction (MeCH), ethyl acetate fraction (MeEA) and water fraction (MeAQ) were determined by agar well diffusion assay along with Minimum Inhibitory Concentrations (MICs). In-vitro antioxidant efficacies were evaluated by DPPH radical scavenging method. Preliminary phytochemical assay, Fourier Transform Infrared Spectroscopy and Gas Chromatography-Mass Spectroscopy analyses were employed to detect the plausible active ingredients. Methanol extract showed broad spectrum antibacterial activity having highest inhibition zone against Staphylococcus aureus MTCC 2940 (21.67±0.58 mm) and MICs ranged from100 µg/ml to 250 µg/ml. The scavenging activity of methanol extract of root of C. album was concentration dependant and IC50 value was 136.08 µg/ml. The lowest MIC (5 µg/ml) was noted with MeCH against B. subtilis (MTCC 441). MeCH showed highest antioxidant activity with an IC50 value of 12.98 ?g/mL and MePET, MeEA, MeAQ and Ascorbic acid presented antioxidant potential with IC50 values of 16.10, 15.07, 17.44 and 13.40??g/mL respectively. Preliminary phytochemical tests and FT-IR analysis revealed presence of various phytochemicals and functional groups like hydroxyl, carboxylic acids, amidines, amines, aromatics and esters. Three compounds were elucidated from bioactive TLC fraction of MeCH in GC-MS analysis supported by presence of various functional groups in MeCH as detected in FT-IR analysis. It is concluded that methanolic extract of C. album root is a potential antibacterial and antioxidant agent where presence of N-[5-[4-pyridinyl)-1H-1,2,4-triazol-3-yl]-benzamide (compound 1), pyruvic acid (compound 2) and methyloacetone (compound 3) are responsible as possible active ingredients.