Antibacterial activity of some seaweeds from the Red Sea coast of Egypt
Egyptian Journal of Aquatic Biology and Fisheries
Keywords: Seaweed antibacterial activity Red Sea pathogenic bacteria Phaeophyta Some commonly occurring brown algae Turbinaria ornata, Cystosiera myrica and Padina pavonica have been collected from the Red Sea coast of Egypt. Three different solvents namely acetone, isopropyl alcohol and ethanol were used for preparing crude algal extracts. The antibacterial activities of crude extracts were evaluated against three pathogens: Grampositive bacteria (Staphylococcus aureus) and Gram-negative
... Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) by disc diffusion method, and then inhibition zones were compared. Strong antibacterial activity was observed for T. ornata, giving high potent with isopropyl alcohol against S. aureus and E. coli, with acetone against P. aeruginosa and with ethyl alcohol against S. aureus (inhibition zone >14 mm). Extracts of P. pavonica and C. myrica showed lower antibacterial activity zones, with no inhibition for most tested trials. Among solvents, isopropyl alcohol showed the highest inhibitory action, followed by acetone with moderate antimicrobial activity while ethanol revealed low antibacterial activity, giving inhibitory action only against Gram positive bacteria (S. aureus). Gram positive bacteria were more susceptible to the algal extracts than Gram negative bacteria. The present study revealed that T. ornata is a promising alga to act as an antimicrobial agent in food products, pharmacology and medical applications.