Antibacterial Potential of Macro and Microalgae Extracts Against Pathogens Relevant to Human Health.

Abstract

The rising need to use natural resources for the production of innovative solutions is increased dramatically. Among these natural resources is algae which is one of the main sources of bioactive compounds. The potential of algae being antimicrobial depends on three factors including its type to be effective against pathogenic bacteria; the solvent used during the process of bioactive compounds extraction; and the concentration of each extract. The biochemical composition of three marine algae Ulva sp. (Chlorophyceae), Sargassum sp. and Hormophysa sp. (Phaeophyceae) Red Sea, Egypt in comparison to three fresh water blue green alga Spirulina sp., green alga Chlorella sp. and Scenedesmus sp. were screened for antibacterial activity against bacterial pathogens with relevance for aquaculture and human health in comparison to antibiotic susceptibility, in addition to the determination of minimum inhibitory concentration (MIC). The fresh water blue green algae Spirulina sp. that represent prokaryotes and the green algae Scenedesmus sp. that represent eukaryotes were selected to be identified molecularlyand the obtained accession number for Spirulina and Scenedesmus were MT897876 and MT900569, respectively. Moreover, Anti-inflammatory study by human red blood cell (HRBC) membrane stabilization method and the In vitro cytotoxicity assay were also determined. The highest ZIsagainst Gram positive bacteria (37 mm) was recorded for ethanol Scenedesmus sp. extract; followed by ethanol Scenedesmus sp. (28 mm). Whereas, for Gram-negative bacteria the highest ZIsvalue was found to be 29 mm with butanol Scenedesmus sp. extract; followed by chloroform Ulva sp. extract (28mm). The cytotoxicity of Spirulina sp. ethanol extract against HCT116 and MCF7 cell lines showed that, small amounts, 26.2 and 43.6 µg/ml were required to inhibit 50% (IC50 ) of HCT116 and MCF7 cell lines, correspondingly. Whereas, higher concentrations of Scenedesmus sp. ethanol extract 58 and 87.7.6 µg/ml were required to inhibit 50% (IC50 ) of HCT116 and MCF7 cell lines, respectively. This study revealed that algal bioactive compounds have potentials as antimicrobials and anticancer.