The MBC was regarded as the lowest concentration of the samples
that allowed less than 0.1% of the original inoculum treated
with the extract or compound samples to survive and grow on the
surface of the medium used. The MBC values were determined
according to the method of Shan, Cai, John, and Cork (2008). In brief,
the samples (50 ml) for theMBC assays were taken from the tubes of
the MIC assays in which any visible turbidity was not observed.
Then, they were spread on freshly prepared nutrient agar plates
and were incubated at 37 C for 24 h so as to determine theMBC values.
After the incubation, the plates were observed for growth. Triplicate
samples were performed for each test concentration.