Phytochemical screening and antibacterial assessment of two macroalgae and (Chlorophyta) against the bacterium .

This study was conducted to determine whether the macroalgae and could be alternatives for preventing vibriosis caused by the bacterium . Phytochemical screening was performed on methanolic extracts to qualitatively determine the main groups of bioactive compounds, previous to an antibacterial test against . Phenols, polyphenols, flavonoids, and the high presence of carbohydrates were found in both macroalgae. showed more presence of lipids and alkaloids than . Macroalgae extracts prepared (v:v) with a 1:1 methanol: dichloromethane solvent was used for the test using the disc diffusion method (MDD). Filter paper discs impregnated with 1.0, 1.5, 2.0, 3.0, and 4.0 mg of the extracts showed antibacterial activity against in a dose-dependent manner in both macroalgae. The inhibition zone varied significantly ( < 0.05) from 8.33 ± 0.12 to 11.41 ± 0.73 mm for 1 to 3 mg of extract levels, respectively. In conclusion, both macroalgae have antibacterial activity in their crude extracts against this bacteria. It is suggested to evaluate it as a feed additive for . This study is the first report on a phytochemical screening and antibacterial activity of these macroalgae against .