“…Indeed, among the aquatic organisms, marine macroalgae represent a rich source of natural antimicrobials (Cox, Abu-Ghannam, & Gupta, 2010;Gupta & Abu-Ghannam, 2011). Antimicrobial activities of seaweed extracts, which displayed an action against a number of Gram positive and Gram negative bacteria, have been previously reported in several studies (Boisvert, Beaulieu, Bonnet, & Pelletier, 2015;Cavallo et al, 2013;Cox, Hamilton, Rajauria, Abu-Ghannam, & Jaiswal, 2014;Gupta & Abu-Ghannam, 2011;Gyawali & Ibrahim, 2014;Mohamed, Hashim, & Rahman, 2012). The most common compounds identified to be responsible for the antibacterial activity of seaweeds are phenolic or lipophilic in nature, fatty acids, secondary metabolites mostly terpenes, alkaloids, polyphenolics and phlorotannins (Ara, Sultana, Qasim, Ehteshamul-Haque, & Ahmad, 2005;Eom, Kim, & Kim, 2012;Gupta & Abu-Ghannam, 2011), which are often halogenated (Watson & Cruz-Rivera, 2003), isoprenoid metabolites (Paul & Puglisi, 2004), hydrogen peroxide (Weinberger & Friedlander, 2000) and lectin (Holanda et al, 2005;Liao, Lin, Shieh, Jeng, & Huang, 2003).…”