Biological Effect of Posidonia oceanica Seaweed on Some Pathogenic Microbes

Abstract

Compared to other coasts, Libyan coasts are characterized by low levels of pollution. This makes them a suitable environment for marine diversity, especially seaweeds, which may be considered a source of new compounds that are biologically active in their resistance to microbes. Therefore, the present study was conducted with the aim of testing the bioactivity of leave and rhizome extracts of Posidonia oceanica seaweed (aqueous, ethanol, and acetone) at concentrations (50, 100, and 150) mg/ml against three types of pathogenic bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa), and fungus (Candida spp.), by a sensitivity test in the form of a disk diffusion method. The results showed that Posidonia oceanica seaweed extracts have good inhibitory activity against S.aureus and Candida spp., and that the concentration of 150 mg/ml is the most effective for all extracts. The results also indicated that rhizome extracts are more efficient than leaf extracts, and the acetone extract is the best in inhibiting the tested microbes. Also, Escherichia coli and Pseudomonas aeruginosa are the most resistant to all extracts, regardless of type and concentration used.