After 20 minutes, the absorbance of the mixture was read at 517nm.
According to the results, compounds 2a, 3a, 3c and 9 showed antibacterial activity against all tested bacteria and compound 3c had the highest activity with inhibition zones ranged 13-16 mm Table 1.
The discs were placed aseptically on the surface of the inoculated solidified plates at equal distances.