Efficacy of medicinal plants against human pathogens isolated from western Himalayas of Himachal Pradesh

Abstract

Objective: The present study was aimed to evaluate the antibacterial effect of Himalayan medicinal plants on several human pathogens. Methods: The leaves of Mesua ferrea, Cannabis sativa, and Urtica dioica, bark of Juglans regia, Glycyrrhiza glabra, fruit of Terminalia chebula, and seed of Piper nigrum were dried and powdered before methanolic extraction (ME). Antibacterial assay of MEs was performed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae using agar well diffusion method. The minimum inhibitory concentrations of these extracts were assessed using microdilution method. The phytochemical analysis of these extracts was carried out to know the bioactive compounds and was fractionated with various solvents such as chloroform, butanol, ethyl acetate, and hexane to isolate the bioactive compound. Results: The ME of C. sativa was found highly active, followed by T. chebula, J. regia, G. glabra, and M. ferrea against these pathogens. While the extracts of U. dioica and P. nigrum found less effective. MIC values of J. regia extract were found much more significant (0.219 g/ml). The antibacterial assay of fractions revealed that the chloroform fraction was highly active against all the pathogens than those of ethyl acetate, butanol, and hexane. Conclusion: It was concluded from the present study that methanol was a good solvent for isolating compounds from medicinal plants and also favors the traditional uses of medicinal plants as antibacterial agents and as a potential source for the new drug discovery. It could also be possible that the compound responsible for antibacterial activity must be present in chloroform fraction of J. regia.