Activities of Albizia Zygia (Fabaceae) Extracts on Salmonella Typhi Bacteria in Aquatic Microcosm: Influence of Some Abiotic Factors

The present study aims at evaluating the activity of aqueous and hydro-ethanolic extracts of Albizia zygia (A. zygia) on Escherichia coli cultures in aquatic microcosms. Bacteria cells were exposed to different concentrations (0.5g/l, 1g/l and 1.5g/l) of aqueous and hydro-ethanolic extracts of A. zygia leaves and/or trunk bark for 3h, 6h and 9h at incubation temperatures of 7°C and 23°C. Phytochemical screening showed the presence of metabolites such as anthraquinones, anthocyanins, flavonoids, polyphenols, tannins and saponines in the two types of extracts. From these experiments we note that bacteria abundance varies according to the concentration of the extracts and the incubation time. In most cases lower abundances are recorded at 23°C in the presence of hydro-ethanolic extract from the trunk bark. The highest rate of cellular inhibition (99.95%) was recorded after 9 hours of exposure of bacteria cells to the hydro-ethanolic extracts from trunk bark at a concentration of 1.5g/l at a temperature of 7°C. The temperature of the environment did not significantly influence bacterial inhibition (P>0.05). In general, the hydro-ethanolic extracts from trunk barks were more effective.

Keywords: A. zygia, phytochemical screening, water quality, bacterial inhibition.