Abstract

The antibacterial activity of crude methanolic extract of Ziziphus mucronata Willd. subsp. mucronata Willd. against both Gram-positive and Gram-negative bacteria were investigated using agar and macrobroth dilution methods. The extract had effective activities against both Gram-positive and Gram-negative bacteria. The agar dilution method indicated that the organisms were susceptible at concentrations ranging between 0.5 and 2.5 mg/ml. While the minimum inhibitory concentration (MIC) values ranged between 0.0391 and 0.625 mg/ml, the minimum bactericidal concentration (MBC) values range between 0.3125 and 1.25 mg/ml. Generally, the Gram-negative bacteria were more susceptible to the extract than the Gram-positive bacteria. The MIC_index indicated that the extract was bactericidal at higher concentrations and bacteriostatic at lower concentrations. Our study revealed the broad-spectrum potential of the plant as well as established its ethnobotanical relevance in the traditional treatment of diarrhoeae and dysentery.

Key words: Ziziphus mucronata, methanol extract, antibacterial assay, macrobroth dilution.