Agar well Diffusion Assay: In vitro antibacterial activity
of different crude extracts of Spirulina platensis was
evaluated using the agar well diffusion assay [9]. 100 μl of
adjusted culture was mixed with 100 ml of Muller Hinton
Agar (MHA) mixed well and poured 25 ml each into sterile
petridishes (90 mm) this was allowed to solidify and then
individual plates were marked for the organisms inoculated.
After solidifi cation plates were punched to make the well of
6 mm diameter with the help of sterile borer. 100 μl of respective
cyanobacterial extracts were pipetted into the well
in assay plates. Plates were incubated overnight at 37°C and
all the plates were observed for the zone of inhibition, diameter
of these zones were measured in millimeters. All the
tests were performed under sterile conditions and repeated
three times. The solvent control revealed no activity.