Antibacterial activities of metabolites from Platanus occidenatalis (American sycamore) against fish pathogenic bacteria

Authors: Schrader, Kevin; HAMANN, MARK - University Of Mississippi; MCCHESNEY, JAMES - Ironstone Separations, Inc; RODENBURG, DOUGLAS - Ironstone Separations, Inc; IBRAHIM, MOHAMED - University Of Mississippi

Submitted to: Journal of Aquaculture Research and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2015
Publication Date: 10/15/2015
Publication URL: http://handle.nal.usda.gov/10113/62231
Citation: Schrader, K., Hamann, M.T., Mcchesney, J.D., Rodenburg, D.L., Ibrahim, M.A. 2015. Antibacterial activities of metabolites from Platanus occidenatalis (American sycamore) against fish pathogenic bacteria. Journal of Aquaculture Research and Development. http://dx.doi.org/10.4172/2155-9546.1000364.

Interpretive Summary: Several natural compounds isolated from the leaves of the American sycamore tree were evaluated in the laboratory using a rapid bioassay for antibacterial activities against four different species of fish pathogenic bacteria. The compounds were determined to possess strong antibacterial activities against two of the pathogenic bacteria species which cause common diseases in pond-raised channel catfish and in several other species of freshwater fish.

Technical Abstract: One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentally safe natural compounds as alternatives to antibiotics would benefit the aquaculture industries. Four natural compounds, commonly called platanosides, [kaempferol 3-O-a-L-(2",3"-di-E-p-coumaroyl)rhamnoside (1), kaempferol 3-O-a-L-(2"-E-p-coumaroyl-3"-Z-p-coumaroyl)rhamnoside (2), kaempferol 3-O-a-L-(2"-Z-p-coumaroyl-3"-E-p-coumaroyl)rhamnoside (3), and kaempferol 3-O-a-L-(2",3"-di-Z-p-coumaroyl)rhamnoside (4)] isolated from the leaves of the American sycamore (Platanus occidentalis) tree were evaluated using a rapid bioassay for their antibacterial activities against common fish pathogenic bacteria including Flavobacterium columnare, Edwardsiella ictaluri, Aeromonas hydrophila, and Streptococcus iniae. The four isomers and a mixture of all four isomers were strongly antibacterial against isolates of F. columnare and S. iniae. Against F. columnare ALM-00-173, 3 and 4 showed the strongest antibacterial activities, with 24-h 50% inhibition concentration (IC50) values of 2.13±0.11 and 2.62±0.23 mg/L, respectively. Against S. iniae LA94-426, 4 had the strongest antibacterial activity, with 24-h IC50 of 1.87±0.23 mg/L. Neither a mixture of the isomers nor any of the individual isomers were antibacterial against isolates of E. ictaluri and A. hydrophila at the test concentrations used in the study. Several of the isomers appear promising for the potential management of columnaris disease and streptococcosis in fish.