Chemical Composition, Antibacterial, and Antioxidant Activity of Methanol Extracts from Aerial Part of Indigofera nummularifolia and Zornia glochidiata

Abstract

The aim of the study is to investigate the chemical composition, antibacterial and antioxidant properties of methanol extracts of Indigofera nummularifolia aerial parts and Zornia glochidiata leaves. The chemical constituents of weighed, air-dried, and pulverized leaf samples of Indigofera nummularifolia and Zornia glochidiata were examined using Gas Chromatography-Mass Spectroscopy (GC-MS). The antimicrobial activities of methanol extract of Indigofera nummularifolia and Zornia glochidiata were tested against six (6) strains of bacteria, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli using agar diffusion pour-plate method. The antioxidant activities of the methanol extracts Indigofera nummularifolia and Zornia glochidiata were carried out using the DPPH method. The methanol extract of I. nummulariifolia showed weak activity against E. coli (5.5 mm). On the other hand, the methanol extract of Z. glochidiata showed significant activity against S. aureus (10.50 mm). The methanol extract of Z. glochidiata exhibits significant antioxidant activity by scavenging DPPH radicals in a dose-dependent manner. The methanol extract of Z. glochidiata exhibited antioxidant activity with IC50 value at 31.15 μg/mL, comparable with that of the standard control, ascorbic acid (IC50 value of 52.10 μg/mL). The GC-MS analyses of the extracts of the two plants revealed various bioactive compounds including fatty acids, carboxylic acids, carboxylic acids esters, terpenes, alcohols, sugars, and other bioactive metabolites. The chemical profiling of the two plants (Indigofera nummularifolia and Zornia glochidiata) employed in this study exhibits broad spectrum of bioactive metabolites with promising antibacterial and antioxidant activities.