Invitro Assessment of Anti Bacterial Effect of Extracts of Ocimum Gratissimum and Carica Papaya Leaves
Ishiwu CN, Umenwanne CP, Obiegbuna JE, Uchegbu NN

Abstract
Extracts of the leaves of Ocimum gratissimum and Carica papaya were assessed for antibacterial activity against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacteria. A 300grams of the fresh leave from each sample was washed, trimmed, sliced, blended and squeezed to extract the liquid. The undiluted extracts at different millilitres were pipetted into prepared Mac Conkey agar plates. Two discrete colonies from pure culture of each bacterium were inoculated into each of these plates and incubated at 37 0C for 24 hours, and the total plate count determined. Similarly, two discrete colonies of the bacterium were inoculated into a prepared Mac Conkey agar plate without the extract (control) and incubated at 37 oC for 24 hours. The result showed that the extracts inhibited bacterial growth as compared with the control. A 5 ml extract of Ocimum gratissimum reduced the visible colonies of S. aureus from 36 cfu/ml to 5 cfu/ml and E. coli from 65 cfu/ml to 14 cfu/ml. A 4.5 ml extract of Carica. papaya exhibited 100 % inhibition of S. aureus and reduced E. coli from 65 cfu/ml to 24 cfu/ml. As the concentration of the extract increases the microbial count decreases significantly (P<0.05). The highest antibacterial activity was achieved using the extract of Carica papaya leaf.

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