Identification of antimicrobial properties of cashew, Anacardium occidentale L. (Family Anacardiaceae)

The antimicrobial capabilities of plant extract derived from the leaves of the cashew plant, Anacardium occidentale L. (Family Anacardiaceae), on two common human pathogens of clinical importance, Escherichia coli and Staphylococcus aureus were investigated. All test organisms were identified to be sensitive to the plant extract, although zones of inhibition were about 50% of those observed using the commercial antibiotic, ampicillin. In terms of sensitivity, S. aureus, a Gram +ve organism, without an outer membrane in its cell wall was more sensitive relative to E. coli, a Gram –ve organism, which possesses an outer membrane in its cell wall. The degree of sensitivity could probably be due to this outer membrane which when present prevents a substantial amount of the extract from making contact with the cell. The antimicrobial properties of A. occidentale are derived from the presence of a polyphenol, anacardic acid and other compounds, tatrols and tanins. Therefore, it is suggestive of the fact that extracts could be used as an antibiotic especially in poor communities.