Ultrastructural
effects of ethyl acetate extract of Lasiodiplodia pseudotheobromae IBRL OS-64 on
foodborne bacterium
Mat Jalil Mohd Taufiq and Ibrahim Darah
Res. J. Chem. Environ; Vol. 26(1); 1-8;
doi: https://doi.org/10.25303/2601rjce001008; (2022)
Abstract
The antibacterial activity of ethyl acetate extract of Lasiodiplodia pseudotheobromae
IBRL OS-64 isolated from the leaf of Ocimum sanctum Linn. was studied and tested
against foodborne bacterium Yersinia enterocolitica. The extract exhibited favourable
antibacterial activity with the zone of inhibition as 20.1±0.6 mm. On the other
hand, minimum inhibition concentration (MIC) and minimum bactericidal concentration
(MBC) values were 250 μg/mL and 500 μg/mL respectively. The extract exerted bactericidal
effect against the test bacterium since the MBC/MIC ratio is less than 4. The time-kill
study of the extract against the test bacterium suggested that the extract possessed
antibacterial properties at higher concentrations and eradicated the growth of bacterial
cells.
The SEM and TEM observations revealed that several abnormalities occurred on the
treated cells including irregular shape, cell’s leakage, shrunken and crumpled cells
which resulted in cell death. Therefore, the present study suggested that the ethyl
acetate extract of L. pseudotheobromae IBRL OS-64 could be an effective antibacterial
agent to combat foodborne pathogens.
