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

Abstract

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 Samonella 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.