Volume 9

April-June 2017

Moringa oleifera leaf potentiates tetracycline activity on Staphylococcus aureus

Okechukwu D C, Kenechukwu F C, Obakpolo L O

Abstract:
The aim of this study was to evaluate the in vitro antimicrobial interaction between the ethanol leaf extract of Moringa oleifera (MO) which is used habitually in Nigeria as a dietery supplement and tetracycline (T). Preliminary antimicrobial sensitivity screening of the extract was carried out using the agar dilution method. The minimum inhibitory concentration (MIC) of the ethanol extract of Moringa oleifera and tetracycline were determined in vitro using the agar dilution method. The antimicrobial interaction was evaluated by the checkerboard technique using Staphylococcus aureus and Pseudomonas aeruginosa. The MICs of the ethanol extract of Moringa oleifera leaf against Staphylococcus aureus and Pseudomonas aeruginosa were evaluated to be 25.0 and 50.0 mg/mL respectively while that of tetracycline was calculated to be 0.0005 and 0.016 µg/mL against Staphylococcus aureus and Pseudomonas aeruginosa respectively. Upon combination, synergism was manifested serially against Staphylococcus aureus in ratios of 9 (T):1(MO) down to 5(T):5(MO) after which additivity was manifested as the ratio of MO increased in the combination. Against Pseudomonas aeruginosa, the combined interaction showed a somewhat irregular pattern of effect, including addtivity at T:MO ratios of 9:1 and 8:2, and synergism at T:MO ratio of 7:3. Other combination ratios had no MIC, hence no observed effect. The combined antimicrobial effect of the interaction between ethanol extract of Moringa oleifera leaf and tetracycline was predominantly synergistic against Staphylococcus aureus.

Keywords: Moringa oleifera leaf, Antibacterial interaction, Checkerboard technique, Staphylococcus aureus, Pseudomonas aeruginosa, Tetracycline.