Resumen

RAMIREZ MERIDA, Luis Guillermo et al. Antimicrobial effect of ethanol extract of leaf neem (Azadirachta indica A. Juss) on Listeria monocytogenes. ALAN [online]. 2016, vol.66, n.1, pp.060-065. ISSN 0004-0622.

Antimicrobial effect of ethanol extract of leaf neem (Azadirachta indica A. Juss) on Listeria monocytogenes. Listeria monocytogenes is a pathogen causing foodborne illness. In seeking to control its spread using natural substances in order to show if the leaf ethanol extract of neem (Azadirachta indica A. Juss) has antimicrobial effect on L. monocytogenes ICTA-12446, was proposed. The extract was obtained from neem leaves, which was subjected to drying for 8 days. It was reduced in size mechanically, and subjected to cold soak for 3 days, using 96% ethanol in amber vessels, filtered and concentrated in rot evaporator. Concentrated was solubilized with dimethylsulfoxide (DMSO) and standarized to achieve a concentration of 60 mg/mL Listeria monocytogenes was inoculated in nutrient broth with extract solutions at different concentrations (20, 30, 40, 50 and 60mg/mL), four contact times (2.5, 5, 10 and 15 minutes) were used. Completed each time it was diluted and inoculated on nutrient agar by extension for 24h at 37ºC. The count of Colony Forming Units UFC was taking. Comparing the concentrations of the extract between 20 and 60mg /mL significant difference was appreciate, while 30, 40 and 50 mg/mL show a similar behavior. Contrasting contact times observed between time 2.5 min and the remaining p = 0.03. The minimum time where there was some kind of inhibition was 2.5 minutes, and minima inhibitory concentration of 20mg/mL. The four contact times yield microbial inhibition percentages of 100% by using 60mg/L. It is concluded that ethanol extract of neem leaf has an inhibitory effect on L. monocytogenes.

Palabras clave : Bacteriostatic; bactericidal; neem; ethanol extract; L. monocytogenes.