Following incubation, 40 ml MTT (3-(4,5-dimethyl-2-thiazolyl)-
2,5-diphenyl-2H tetrazolium bromide) (0.2 mg/ml) was added to
each well and incubated at room temperature for a further
10e15min. Bacterial growthwas observed as a pink-red coloration of
the wells. The well of lowest concentration of extract in which bacteria
growth was prevented, no pink-red coloration was observed,