PRELIMINARY PHYTOCHEMICAL AND ANTIBACTERIAL STUDIES ON LEAF EXTRACTS OF ALTERNANTHERA BRASILIANA (L.) KUNTZE

Abstract

Objectives: The present study was to study the phytochemical and antibacterial properties of Alternanthera brasiliana leaf extracts using three different solvents (hexane, chloroform and methanol) against human pathogenic microorganism. Methods: Preliminary phytochemical screening of leaf extracts (in different solvents) of A. brasiliana were qualitatively tested using standard procedures. Thin Layer Chromatography (TLC) was performed to detect the phytochemical compounds present in A. brasiliana . Antibacterial activity of crude extract was determined by disc diffusion method. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were also performed for the hexane extract. Results: The preliminary qualitative phytochemical screening of hexane extracts revealed the presence of alkaloids, phenols, flavonoids, saponins, tannins, phytosterols and carbohydrates. In chloroform and methanolic extracts, all the tested phytochemicals were present except flavanoids and saponins. Alkaloids were not present in the chloroform extract. TLC analysis revealed the presence of seven compounds with R f values ranging from 0.173 to 0.933. Promising antibacterial activity was observed in the hexane extract with an inhibition zone of 22 mm against E. coli. Chloroform and methanolic extracts showed negligible antibacterial activities. Conclusion: The results revealed that the hexane leaf extract of A. brasiliana alone exhibited potential antibacterial activity specifically against pathogenic E. coli (MTCC 729). Keywords: Antibacterial activity, Alternanthera brasiliana, E.coli, Phytochemical, Flavanoid