A Newly Observed Inhibitory Effect of Cashew Nut Extract on the Growth of Pathogenic Microorganisms

Abstract

The antimicrobial activity of alcoholic extract of cashew nut ( Anacardium occidentale ) was tested on some pathogenic microorganisms collected from the laboratory. Fresh cashew nuts were macerated and extracted using absolute methanol at a dilution ratio of 1:2 (w/v) for 24 hours at room temperature (28°C). This extract was filtered using a Whatman filter paper No. 40 into a conical flask and the filtrate heated at 60°C for 30 minutes to remove the methanol. The filtrate was used to fill 5mm diameter wells on nutrient agar plates. A total of 120 organisms comprising 20 Proteus species , 20 Pseudomonas aeruginosa , 10 Candida albicans and 10 Enterococcus faecalis were used for this assay. The following organisms were susceptible to crude extract of cashew nut with mean zone diameters of 14mm for Escherichia coli , 22mm for Pseudomonas aeruginosa , 19mm for both Staphylococcus aureus and Klebsiella species, 13mm for Enterococcus faecalis , 14mm for Proteus species and 10mm for Candida albicans . This study shows that cashew nut extract has antimicrobial activity against a reasonable range of pathogenic microorganisms. Key words: cashew nut, crude extract, microbial inhibition Journal of Medical Laboratory Science Vol.13(1) 2004: 58 - 61