The inhibitory effects of the samples were determined
using a modified double layer technique with 5-mm paper
discs [28]. The arid extract samples were individually dissolved
in DMSO at a concentration of 100 mg·mL−1
, and then
diluted to 100 μg·mL−1
as test-solutions with aseptic distilled
water. Microbe suspension (for bacteria) or spores suspension
(for fungi) was mingled with LB or PDA medium, and the
final concentrations were 2−5 × 107
cells/mL. The testsolution
(10 μL) was added onto each filter paper disc placed
on the surface of assay plates. After incubation at 37 o
C (for
bacteria) or at 28 o
C (for fungi) for 24−48 h, the diameter Φ
of inhibition zones around each disc were measured. The
antimicrobial activity was qualitatively evaluated as very
strong if Φ was greater than 15 mm. The evaluation scale is
shown in Table 2