Abstract

IN VITRO ANTIMICROBIAL POTENTIAL, BIOSAFETY AND BIOACTIVE PHYTOCONSTITUENTS OF MORINGA OLEIFERA STEM BARK

Daljit Singh Arora* and Jemimah Gesare Onsare

Abstract

M. oleifera is known for its nutritional and numerous medicinal uses that have been appreciated for centuries in many parts of its habitat and introduced ranges. Stem bark of this plant, has been traditionally used for stimulation purposes as well as antimicrobial and other pharmacological disorders. This work evaluated the stem bark of this plant for its antimicrobial potential by determining the minimum inhibitory concentration (MIC), time kill assay and post antibiotic effect (PAE) against some human pathogens of yeast strains, Gram positive and Gram negative bacteria. Its safety was ascertained by Ames test and MTT assay, qualitative and quantitative analysis of phytoconstituents and their antimicrobial activity was established. Multiple means were compared by ANOVA at 5% confidence level. Antimicrobial activity of various solvents extracts indicated acetone to be the best extractant and hence was used to evaluate subsequent in vitro studies. The extract exhibited a broad spectrum potential and was neither mutagenic nor toxic. Klebsiella pneumoniae 1, Pseudomonas aeruginosa and interestingly methicillin resistant Staphylococcus aureus (MRSA) were the most sensitive with a minimum inhibitory concentration (MIC) of 0.1mg/ml. The Gram positive bacteria showed susceptibility within a time kill range of 6 h – 10 h as compared to Gram negative bacteria which ranged from 10 h – 24 h. Among the major phytoconstituents established, flavonoids and diterpenoids exhibited broad spectrum properties. These findings indicate that Moringa oleifera stem bark, could be a potential source of active principals for development of broad spectrum drugs or drug leads.

Keywords: antimicrobial; Moringa oleifera; phytoconstituents; pharmacodynamics; broad spectrum; stem bark