In vitro assessment of the antimicrobial activities of leaf and stem extracts of Alchornea cordifolia

In vitro assessment of the antimicrobial effect of leaf and stem extracts of a commonly used plant - Alchornea cordifolia was carried out on 10 bacteria and 5 fungi. Five solvents- chloroform, methanol, ethanol, petroleum ether and water were used for extraction. Chloroform extract from leaf and stem resulted in the highest zone of inhibition against the test bacteria (33 - 56mm). Ethanol extracts showed inhibition zone ranging between 10 - 14mm; methanol extract showed inhibition zone of 13 - 21mm only for the leaf extract. Petroleum ether extract of only the stem resulted in inhibition of the test bacteria (10 - 15mm). Leaf and stem water extracts did not result in any zone of inhibition. Only chloroform extracts from both leaf and stem resulted in fungal growth inhibition ranging from 22 - 60mm (leaf) and 14 - 40mm (stem). Staphylococcus haemolyticus was most sensitive to leaf chloroform extracts (50mm), followed by E. coli (49mm); while Salmonella sp. was the most sensitive to stem extracts (56mm). Rhizopus sp. was the most sensitive to both chloroform leaf extracts (60mm) and stem extracts (40mm) out of the 5 fungi screened. The highest minimum inhibition concentration (MIC) of 0.125mg/ml was obtained from the leaf chloroform extract on Pseudomonas sp. The implication of the findings was discussed.