Role of African spices against Escherichia coli isolated from potable water sample in Sokoto, Nigeria

Abstract

The antibacterial activity of five selected spices against Escherichia coli was carried out using agar well diffusion method. Two solvent were used for extraction (ethanol and hot water), the extract were prepared at different concentration (20, 30, 40, 50 and 90 mg/ml). At 90 mg/ml concentration of ethanol extracts Zingiber officinale (11 mm), Allium sativum (9.0 mm), Syzygium aromaticum (5 mm) and that of hot water extracts the zone of inhibition were: Z. officinale (5.0 mm), A. sativum (4.0 mm), S. aromaticum (2.0 mm) while Xylopia aethiopica and Piper umbellatum do not showed any activity against the E. coli of both ethanol and hot water extracts. The standard of seven antibiotics used (control) for comparison only ciprofloxacin was observed to be effective against E. coli. The autoclave extracts do not have any activity against the test organism even at high concentration. The minimal inhibitory concentration and minimal bactericidal concentration were also determined. We observed that the ethanol extracts were more affective against the E. coli than that of hot water extracts. The phytochemical analysis showed the presence of tannins, flavonoids, saponins, steroids and alkaloids in varying concentration.

Keywords: Africa, spices, Escherichia coli, isolated water.