Chemical and biological properties of green freshwater alga Ulva intestinalis collected from Casablanca, Morocco

Ulva intestinalis ( U. intestinalis ) is a widespread tubular green macroalga that serves as a valuable natural reservoir of carbohydrates, proteins, and minerals, with minimal lipid content. This research focuses on assessing the antioxidant and bio-fertilizing properties of U. intestinalis, as well as analyzing the primary and secondary metabolites extracted from this alga collected in Dar Bouazza, situated 17 km from Casablanca, Morocco, as part of the overall evaluation of algal biomass. The antioxidant potential of crude extracts was investigated through DPPH • (2,2-diphenyl 1-picrylhydrazyl) and ABTS •+ (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid) free radical scavenging assays. The findings indicated that the ethanol extract exhibited superior activity compared to all other tested extracts. To evaluate its bio-fertilizing efficacy, germination tests were conducted. Results revealed that the aqueous extract of this macroalga demonstrated bio-fertilizing effects at various concentrations. Conversely, the algal powder of U. intestinalis exhibited a germination antagonistic effect. Chemical analysis of this alga indicated a substantial ash or mineral content (61.2 %), followed by carbohydrates (21.3 %) and proteins (10.6 %). The fat content was low (0.5 %), with palmitic acid being the predominant saturated fatty acid. U. intestinalis stood out for its remarkable sodium richness and high polyphenols content.