Olive oil by-product's contribution to the recovery of phenolic compounds from microalgal biomass: biochemical characterization, anti-melanogenesis potential, and neuroprotective effect

Recently, the use of microalgae in the treatment of olive mill wastewater as a safe method for reducing pollutants has gained more attention. However, the contribution of such by-product to the improvement of the pharmacological properties addressing the health benefits of Scenedesmus sp., as a cosmetic remedy or food ingredient, is not sufficiently available. To address this issue, Scenedesmus sp. was cultivated in BG11 medium enriched or not with 20% of ultra-filtrated olive mill wastewater (UFOMW) and polyphenols were then extracted, identified, and quantified by HPLC-DAD analysis. Their antioxidant capacity, enzymatic inhibition, potential in inhibiting lysozyme aggregation, B16 and HeLa cell proliferation, cytotoxic effect against healthy cells, and their intracellular anti-melanogenic effect were assessed, up to our knowledge, for the first time in this study. The addition of UFOMW enhanced the production and apparition of some phenolic compounds with low cytotoxicity on normal versus cancer cells. UFOMW improved the antioxidant capacity and promoted melanogenesis, enzyme, and lysozyme inhibition. Interestingly, Scenedesmus sp. cultured in the presence of UFOMW may provide a valuable source of safe antioxidants with an enhanced biological potential that can be commercially exploited in the food and/or pharmaceutical industries.