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Aim: To determine the phytochemical composition and antimicrobial properties of tamarind extracts on some aquatic pathogenic bacteria.
Study Design: Completely Randomized Design (CRD).
Place and Duration of the Study: Department of Animal Production, Fisheries and Aquaculture, Kwara State University, Malete, Nigeria, between August 2014 and April, 2015.
Methodology: The phytochemical constituents in ordinary, warm and hot water as well as ethanol extracts of tamarind seed coat, pulp and leaves were screened. The Zone of Inhibition (ZOI) diameter (mm), Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against some aquatic pathogenic bacteria were determined. Data were analyzed using ANOVA at P = .05.
Results: The result revealed presence of reducing sugar, flavonoid, saponin and terpenoids in all tamarind extracts. The synthetic antibiotics used had significantly higher ZOI than the tamarind extracts for all the test organisms. Tamarind pulp hot water extract significantly inhibited Aeromonas hydrophila and Hafnia alvei than other extracts while the leaf warm water extracts had significantly higher zone of inhibition against Pseudomonas putida. The best MIC was obtained for oxytetracycline and erythromycin against Enterobacter gergovia and Escherichia coli respectively. Pulp extracts and erythromycin exhibited the same MIC, 2.56 mg/ml, for Bacillus subtilis and H. alvei while the former had lower MIC (2.56 mg/ml) against Salmonella typhi than the MIC (5.12 mg/ml) of the later. Oxytetracycline and tamarind extracts also demonstrated the same MIC (2.56 mg/ml) against S. typhi. Pulp extracts exhibited MBC for most of the test organisms.
Conclusion: Warm tamarind leaf and hot tamarind pulp aqueous extracts demonstrated better antimicrobial activities against some bacteria used in this study and hence the extracts could be used to control such microbes associated with the aquatic environment and fish products.