Comparative study of antibacterial activity of some medicinal plants extracts against strains of Salmonella isolated from guinea fowl in Benin

Abstract

The present work has compared the in vitro effectiveness of ethanolic and semi-ethanolic extracts of Annona muricta, Thalia geniculata and the essential oils extracted from Cymbopogon citratus, Syzygium aromaticum and Ocimum gratissimum against strains of Salmonella Oakland, Salmonella Farakan, Salmonella Kingston and Salmonella Legon, one of causes of the keet deaths in farms recorded in Benin.. These effectivenesses had been assessed by the agar diffusion method and microdilution technic using 96 wells microplate. The results obtained from this test showed that non-volatile extracts of Annona muricata and Thalia geniculata have no antibacterial activity on the four strains tested. By contrast, the essential oils of Cymbopogon citratus, Syzygium aromaticum and Ocimum gratissimum have shown relative antibacterial effectiveness to these four strains with inhibitory diameters of strains varying between 10 to 11 mm for Cymbopogon citratus oil, 14 to 18 mm for Syzygium aromaticum and 20 to 24.5 mm for Ocimum gratissimum. The oil of Ocimum gratissimum has thus proven to be the most active on the strains followed by that of Syzygium aromaticum. Although the essential oil of Ocimum gratissimum presents the strongest activity among all the extracts, its activity remains low (p< 0.05) compared to that of ciprofloxacin.