Determination of antimicrobial activity
Antimicrobial activity of the aqueous and organic extracts of the plant sample was evaluated by the paper disc diffusion method4 .
For determination of antibacterial activity, bacterial cultures were adjusted to 0.5 McFarland turbidity standard and inoculated onto Nutrient agar (oxoid) plates (diameter: 15cm).
For the determination of antimycotic activity, all the fungal isolates and Candida albicans were first adjusted to the concentration of 106 cfu/ml.
Cultures of Candida albicans were suspended in sterile solution of 0.9% normal saline and the spores of the other filamentous fungi were suspended in Tanquay buffer and all the cultures were inoculated onto Sabroud Dextrose Agar plates.
Sterile filter paper discs (diameter 6mm for bacteria and 13mm for fungi) impregnated with 100µl of extract dilutions reconstituted in minimum amount of solvent at concentrations of 50 and 100mg/ml were applied over each of the culture plates previously seeded with the 0.5 McFarland and 106 cfu/ml cultures of bacteria and fungi respectively.
Bacterial cultures and those of Candida albicans were then incubated at 37o C for 18 h while the other fungal cultures were incubated at room temperature (30 – 32o C) for 48 h. Paper discs impregnated with 20µl of a solution of 10mg/ml of ciprofloxacin and cotrimoxazole (for bacteria) and nystatin and amphoteracin B (for fungi) as standard antimicrobials were used for comparison.
Antimicrobial activity was determined by measurement of zone of inhibition around each paper disc.
For each extract three replicate trials were conducted against each organism.