ABSTRACT

The plant Andrographicspaniculata has a high antimicrobial activity against selective food borne pathogens such as Staphylococcus sp, Escherichia coli, Salmonella sp, Bacillus sp, Shigella and Pseudomonas sp. The extracts ofthe plant were used to conduct a time kill kinetics on the selective food borne pathogens. The present study was conducted to investigate the antimicrobial effect of Andrographispaniculata against selective food pathogens. The plant parts of A. paniculata such as leaf, stem and root were studied for its antimicrobial activity. Different solvents were used to extract the active components from the plant parts. The antimicrobial activity was studied against selective food pathogens viz., Staphylococcus sp., Escherichia coli, Salmonella sp., Bacillus sp, Shigella and Pseudomonas sp. Among the different solvents the water extract caused inhibitions with diameters in the range of 10.33mm to 12.33mm. Staphylococcus aureus ,Bacillus, and Shigella were all inhibited to the same level (10mm) by the water extract while E-coli, Pseudomonas and Salmonella were inhibited with diameters of 11.33mm, 11.67mm, and 12.33mm respectively. The antimicrobial activity of the ethanol extract of A. Paniculata was in the range of 15.33mm {Staphylococcus') to 20.33mm {Pseudomonas'), result of minimum inhibitory concentration ofthe plant extract against the food borne pathogens. The water extract had minimum concentration that caused inhibition in the range of lOOmg/ml while that of the ethanol extract was between 50mg/ml and lOOmg/ml. The least concentration of water extract to effect inhibition was 150mg/ml for each of the pathogens except with Salmonella that was inhibited at a minimum concentration of lOOmg/ml ofthe extrac