Bioprospecting microalga Scenedesmus obliquus as a source of lipids with anti-inflammatory and antioxidant activity ; Bioprospeção da microalga Scenedesmus obliquus como fonte de lípidos com atividade anti-inflamatória e antioxidante

Scenedesmus obliquus is a green microalga that has in its biochemical composition a high content of omega-3 polyunsaturated fatty acids (PUFA), especially alpha-linolenic acid (ALA), which are mostly esterified to polar lipids. This is an essential fatty acid with high nutritional value that must be obtained through the diet. Omega-3 PUFA play important biological roles and health benefits, particularly in the prevention of inflammation-related non-communicable diseases. Hence, the polar lipids of Scenedesmus obliquus, rich in omega-3 PUFA, are a potential source of compounds with nutritional value, but also with potential bioactive properties. However, its polar lipid content remains scarcely explored. Therefore, the aims of the present work were (a) bioprospecting the Scenedesmus obliquus extracts obtained by dichloromethane:methanol (2:1 v/v) extraction (DCM) and with ultrasound probe-assisted ethanol extraction (EtOH+UAE) and also phospholipid + betaine- (PL+BT-) and glycolipid (GL)-enriched fractions as a source of added value polar lipids with anti-inflammatory and antioxidant properties and (b) correlate the bioactive potential of these extracts and enriched fractions with their polar lipid composition obtained using a reversed-phase liquid chromatography mass spectrometry-based untargeted lipidomics approach for a detailed identification and characterization of the extracts and fractions with anti-inflammatory and antioxidant potential. The extracts (DCM and EtOH+UAE) as well as the PL+BT- and GL-enriched fractions showed anti-inflammatory potential both in chemico through the inhibition of COX-2 activity, and in vitro by reducing the nitric oxide production and the transcription of pro-inflammatory genes, including Il1β, Ptgs2, Tnfα and Nos2 in lipopolysaccharide-stimulated macrophages. Besides, the extracts and fractions under study also showed antioxidant potential, being able to scavenge the ABTS●⁺ and DPPH● radicals in chemico, and to reduce intracellular oxidative stress in vitro, in Jurkat ...