Antibacterial Screening of Leaves Extracts of Annona muricata (Annonaceae) and Jatropha tanjorensis (Euphorbiaceae) against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa
N. E. Ewa-Udu
Department of Microbiology, Madonna University, Elele, Rivers State, Nigeria.
F. C. Nwanebu *
Department of Microbiology, Madonna University, Elele, Rivers State, Nigeria.
H. O. Stanley
Department of Microbiology, University of Port Harcourt, Rivers State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The crude extracts of Annona muricata and Jatropha tanjorensis leaves were investigated with the aim of determining the antibacterial activity, qualitative and quantitative properties, combination properties. Ethanol, petroleum ether and water (distilled) were used as solvents. Agar well diffusion method was used for the susceptibility testing of extracts against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, with ciprofloxacine as positive control and Dimethyl as negative control. Ethanol and petroleum ether extracts of the plant, either alone or in combination, showed activities against test organisms. P. aeruginosa was more susceptible to ethanolic extract of A. muricata extract with 11.33±0.33mm zone of inhibition while E. coli was the least susceptible with 9.83 mm. E. coli was more susceptible to ethanolic extract of J. tanjorensis with 10.0±0.00 mm zone of inhibition while P. aeruginosa was the least susceptible with 9.0±0.0 mm diameter. Using petroleum ether, E. coli was the most susceptible to A. muricata extract with 7.33±0.33mm while S. aureus was the least susceptible with 7.00±0.58mm diameter. For J. tanjorensis petroleum ether extract, E. coli was the least susceptible with 7.33.0±0.33 mm zone of inhibition while S. aureus was the most susceptible with 8.0±0.0.58 mm diameter. The combination of petroleum ether extracts of both plants gave zones of inhibition of 7.67±0.67 mm and 8.33±0.67 mm for E. coli and S. aureus respectively. The combination of ethanolic extracts of both plants gave zones of inhibition of 14.33±0.67 mm, 12.60±0.6 mm and 7.67±0.33 mm E. coli, S. aureus and P. aeruginosa respectively, which suggest a synergistic effect. The minimal inhibitory concentration of the extracts against test organisms ranged between 25 mg/mL and 100 mg/mL while the minimal bactericidal concentration ranged between 50 mg/mL and 100 mg/mL. This study reveals that the ethanol and petroleum ether extracts of A. muricata and J. tanjorensis have antibacterial effect on E. coli, S. aureus and P. aeruginosa.
Keywords: Annona muricata, Jatropha tanjorensis, antimicrobial, synergistic effect