Disc diffusion assay
The antimicrobial activity of extracts was evaluated using a
slightly modified agar disc diffusion method (Barry, 1976). A bacterial
culture grown for 18 h was serially diluted in 9 ml of 0.1% peptone
to obtain 105 cfu/ml and 100 ll spread on the surface of
Mueller Hinton (MH) agar in Petri plates. An aliquot (10 ll) of herb
and spice extract was pipetted on a sterile paper disc (Whatman
No. 1, 5.5 mm paper disc) on the agar surface. Except in the case
of hexane extracts the discs were air dried to evaporate the ethanol.
A disc impregnated with an aliquot (10 ll) of Streptomycin
(Fluka, Switzerland)