Munirat A. Idris, Suleyman A. Muyibi, Mohd Ismail Abdul Karim Parveen Jamal, Hamzah Mohd. Salleh, Mohammed Saedi Jami
Bioenvironmental Engineering Research Centre (BERC), Biotechnology Engineering Department, Faculty of
Engineering, International Islamic University Malaysia (IIUM), P.O. Box 10 Jalan Gombak, Kuala Lumpur, 50728, Malaysia.
Earlier research conducted on moringa oleifera seed extract not only reveals its excellent coagulant property; it also being
proven to possesses antibacterial activity against microorganism. An antibacterial agent 4 (α-L- rhamnosyloxy) benzyl
isothiocyanate, a plant synthesized derivatives of benzyl isothiocyanates has been identified as the active antibacterial agent
present in the seed. In this study, the mode of antibacterial action was determined using the kill-time study on e.coil and
pseudosomonas aeruginosa bacterial strains. The minimum inhibitory concentration (MIC) assay was done using macrodilution
broth. MIC values were varied from 0.0125mg/ml to 0.1mg/ml. Kill-time assay was carried out based on standard procedure.
The growth of the microbes was monitored for every 30 minutes by viability counting on agar plate. Log reduction of viable
cells counts ranged from 0 to 3.6 log10 for e.coil and 1log10 to 4log10 for p.aeruginosa. The results of the kill-time study
revealed that the extract was bactericidal against e.coli and p.aeruginosa within 30 minutes of contact resulting in about 90%
elimination of the strains. Most of the microbes were killed at high MIC value of 0.1 mg/ml, which might suggest that the seed
extract exhibits concentration-dependent killing.