Phytochemical Studies and Antibiofilm Activity of Annona Senegalensis Plant Extracts against Three Diarrhoeagenic Bacteria

ABSTRACT

The aim of this study was to evaluate the stem and root extracts of Annona senegalensis for phytochemical analysis and determine the antibiofilm activity against Salmonella typhimurium, Shigella flexneri and Escherichia coli. Collection of plant and bacterial stock samples followed standard practices. Plant stem and roots extracts were prepared using aqueous and methanolic methods of cold maceration and tested for the presence of various phytochemicals. Quantitative assessment of active ingredients was carried out using spectrophotometric method. Stock samples of bacteria were sub-cultured on a nutrient agar and the isolates were subjected to confirmatory tests using cultural, microscopic and biochemical characteristics. Qualitative and quantitative biofilm assays were carried out using the tube method. Data were analyzed using descriptive and inferential methods on the Minitab software. While confidence limit was set at 95% level. Results of phytochemical screening revealed the presence of all phytochemicals tested in the methanolic root and stem extracts. Methanolic root had the highest amount of saponin (1.57%), terpenoid (3.39%) and flavonoid (3.44%). Aqueous stem had the highest amount of phenol (4.30%), steroid (4.71%) and cardiac glycoside (1.9%) while aqueous root had the highest amount of tannin (1.29%) and alkaloid (1.12%). The phytochemicals had significantly varied quantity in the plant (F = 6.60, (P<0.05) but the extract types used had similar effect. The root had the highest percentage distribution of phytochemicals (26%) regardless of the extraction method used followed by the aqueous stem (25%) and methanolic stem (23%). Among the phytochemicals, the mean quantity of phenol was the highest (3.845) followed by steroid (3.1%) and terpenoid (2.58%). Biofilm formation was moderate in S. typhimurium (++) but weak the other two (+). Result of biofilm inhabitation assay of A. senegalensis plant showed that methanolic extracts (stem and root) performed better than the aqueous method, as low as 12.5mg/ml in S, flexneri.  Results have proven the potentials of the plant stem and root as a possible remedy for gastro-intestinal diseases and diarrhoea due to the presence of all basic active ingredients that were earlier reported to have antibacterial effects and due to the antibiofilm activities of the methanolic extracts..