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 oC (for
bacteria) or at 28 oC (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.