Seasonal variability of the Phenolic profiles of algae Cymopolia barbata and Lobophora variegata

Abstract

Phenolic profiles of Cymopolia barbata (C. barbata) and Lobophora variegate (L. variegate) strains collected from Las Canteras beach (Gran Canaria) in different seasons (January, April, August and November 2021) were studied. Algae were washed, cleaned and freeze-dried. Chromatographic analysis was performed with a Jasco LC-4000 HPLC and a Varian C18 column according to a previously reported method (Rico et al., 2013; Santiago-Díaz et al., 2021). Simultaneous monitoring for quantification was set at 270 nm (gallic acid (GA), protocatechuic acid, catechin, vanillic acid, rutin, epicatechin, and syringic acid). GA was the only compound detected in C. barbata methanolic extracts, ranging from 10.1 μg g-1 of dry biomass in samples collected in April to 4.39 μg g-1 of dry biomass in samples collected in November. GA was also identified in all samples of L. variegate (18.7, 7.95, 5.66 and 4.50 μg g-1 of dry biomass collected in August, April, January and November, respectively) (López et al., 2011). Relevant amounts of epicatechin and syringic acid were also quantified in L variegata strains collected in January (29.6 and 5.66 Aμgn tgio-1x riedsapnetc taivcetilvyi)t.i es of C. barbata extracts were determined using 1,1-diphenyl-2- picrylhydrazyl free radical (Bondet et al., 1997). Samples collected in August and January exhibited the highest radical scavenging activities (79.6 and 75.5% respectively). All the extracts gave higher activity than that shown by the food preservative butylhydroxyanisole (62.5%). The extracts were also subjected to the ferric reducing ability of plasma assay and showed similar results: samples of C. barbata colleted in August and January exhibited the highest activities (0.169 and 0.146 μmol of Fe3+ reduced to Fe2+ equivalents g-1 of dry biomass respectively). The amounts of phenolic compounds found in both strains and the antioxidant activities of samples collected in different seasons might be linked to climatic, other ecologic, and/or genetic factors.