Preliminary Phytochemical Screening and Antibacterial Activity of Ocimum gratissimum against some Enterobacteriaceae

Abstract

Medicinal plants have bioactive compounds which are used for curing and healing various human diseases. This study aimed at investigating the phytochemical and antibacterial potentials of Ocimum gratissimum leaves against some Enterobacteriaceae. Fresh leaves of Ocimum gratissimum were collected from a farm at Unguwan rimi, Kaduna State, Nigeria. The leaves were washed, air dried under shade and grinded to powder. Extraction was carried out using ethanol and methanol by cold maceration. The phytochemical screening was carried out using standard procedure, while the antibacterial activity was determined using agar well diffusion at a concentration range of 500-62.5mg/ml. The result shows the presence of phenol, tannins, saponins, cardiac glycosides and steroids for both ethanolic and methanolic extracts. The antibacterial activity of ethanolic extract of O. gratissimum against Escherichia coli, had a mean zone of inhibition range of 20.84±4.71 - 13.8±1.84, while methanolic extract had a mean zone range of 21.6±4.90 - 15.2±1.97. Ethanolic extract of O. gratissimum against Klebsiella had a mean zone of inhibition range of 25.5±4.40 - 18.2±1.50, while the methanolic extract varied from 20.5±5.0 - 6.00±0.00. Ethanolic extract of Ocimum gratissimum against Pseudomonas aeroginosa varied from 19.5±2.76 - 14.2±1.70, while methanolic extract was from 21±7 - 14.5±5. The MIC of ethanolic extract against E. coli was 250mg/ml and methanolic extract 125mg/ml, while the MBC for both the ethanolic and methanolic extracts was 250mg/ml. The MIC of ethanolic extract of Klebsiella was 500mg/ml, and methanolic extract was 250mg/ml, while the MBC for ethanolic extract was 500mg/ml, and methanolic extract 250mg/ml. For Pseudomonas aeroginosa MIC of ethanolic extract was 500mg/ml, and 250mg/ml for methanolic extract, while the MBC for ethanolic extract was 500mg/ml, and 250mg/ml for methanolic extract. The result suggests that O. gratissimum could be considered as a good antibacterial agent.