and transferred to sterile 15-cm diameter Petri dishes. The medium in the plate was allowed to set at room temperature for 10 minutes and solidify for 30 minutes. Three wells (6-mm inner diameter) were made in each plate. Stock solutions of the test residual extract were prepared at concentrations of 100, 300, and 500 mg/mL. One hundred microliters of each concentration was placed in the well with sterile pipettes. In each plate, 1 well was used for the control, standard, and test respectively. Chloramphenicol (100 μg/mL) was used as the standard, and the respective solvent was used as the control. The petri dishes were incubated for 16 h at 37ºC and examined with regard to size of the zones of inhibition. Methanol was used as the control. The length of the inhibition zone was measured in millimeters from the edge of the well to the edge of the inhibition zone, and the results were tabulated.