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

摘要

In vitro assessment of the antimicrobial effect of leaf and stem extracts of acommonly used plant – Alchornea cordifolia was carried out on 10 bacteria and 5 fungi. Fivesolvents– 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 thetest 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 chloroformextracts 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 leafchloroform extracts (50mm), followed by E. coli (49mm); while Salmonella sp. was the mostsensitive to stem extracts (56mm). Rhizopus sp. was the most sensitive to both chloroformleaf extracts (60mm) and stem extracts (40mm) out of the 5 fungi screened. The highestminimum inhibition concentration (MIC) of 0.125mg/ml was obtained from the leafchloroform extract on Pseudomonas sp. The implication of the findings was discussed.