The microbroth dilution test was performed to determine minimum
inhibitory concentrations (MICs) using the procedure as described
by Jorgensen et al., 1999. 100 µl of Mueller-Hinton broth (MHB, for
bacteria) or SDB (for yeasts) were added into each well of a microtiter
plate. The 100 µl aliquot of stock solution of crude methanolic
extract (400 mg/ml) was added and subsequently 2-fold serially diluted
with broth. The cell suspension (20 µl) at concentration of 10
7
cells/ml was added into each well. The final concentrations of the
extracts ranged from 166.7 to 2.6 mg/ml. The negative control were
also performed using 10% DMSO. Penicillin G (50,000 - 0.005
unit/ml) was used as a positive control drug. Duplicate wells were
run for each concentration of the extracts. After incubation, the turbidity
was measured at 620 nm using the microplate reader (iEMS
Reader MF, Labsystems). The lowest concentration that inhibited
visible growth was recorded as the MIC.