Plants with medicinal value produce certain chemical elements known as phytochemicals that have antibacterial activity. The study was aimed at determining the antibacterial activity of Vernonia amygdalina against bacterial isolates using agar well diffusion method. In addition, the phytochemicals analysis of the extracts was also determined. The phytochemical analysis showed the presence of saponins, steroids, terpenoids, tannins, alkaloids, and flavonoids. The result of Vernonia amygdalina showed that the average zones of inhibitions observed against these bacterial ranges from 6-22mm. The highest zone is also exhibited against E. coli with average diameter of zone of inhibition of 22mm. At 100mg/ml concentration for Samonella, the zone of inhibition was recorded to be 21mm while at 12.5mg/ml there was no inhibition. At 25mg/ml and 12.5mg/ml, against Pseudomonas there was no inhibition. In other to further confirm the activity of these plant extracts, the minimum inhibitory concentration and minimum bactericidal concentration was determined and the result showed that the extract exerted good antibacterial activity on all the test organisms at different concentration. The result of minimum inhibitory concentration ranges from 10 to 12.5mg/ml and that of MBC ranges from 5 to 20mg/ml. It is worthy to note that MBC values is greater than that of minimum inhibitory concentration. The study provides insight into the antibacterial activities of the plant extracts and its use in the treatment of bacterial infections.
