Fucoidan content and composition of Colpomenia sinuosa and Myriogloea major from Argentine Patagonia

DELLATORRE FERNANDO G.; PONCE NORA M.A.; RAFFO P.; LATOUR, EZEQUIEL A.

Chiba

Conferencia; 7th Conference of the International Society For Applied Phycology; 2021

International Society for Applied Phycology

Cell walls of brown seaweeds contain fucoidan, a class of sulfated polysaccharide with intense bioactivity and increasing commercial applications. A common trait of brown seaweeds fucoidans is their high content of L-fucose residues and sulfate. Instead, fucoidan from different species show variable amounts of other sugars like galactose, mannose, xylose, rhamnose, arabinose, glucose or glucuronic acid, and have also variable structural characteristics [1]. Bioactivity of fucoidans is determined by its chemical composition and structure, and consequently linked to biological origin. In this work we present preliminary data on fucoidan yield and sulphate and monosaccharide composition of Colpomenia sinuosa (Mertens ex Roth) Derbès & Solier and Myriogloea major Asensi. Samples were taken from an intertidal rocky shore in the southwest margin of Golfo Nuevo (Patagonia, Argentina) between January and May 2019. Macroalgal thalli were cleaned, washed, air dried and milled. Fucoidan extraction technique was adapted from Ponce et al. [2], briefly, an acid (0.01 M HCl; pH = 2) extraction (6 h at room temperature) followed by, centrifugation, filtration, dialysis and lyophilization. Total carbohydrates in dried extract were determined by the phenol-sulphuric method using fucose as standard. The sulfate content was determined turbidimetrically [2]. Uronic acid content was determined according the method of Filisetti-Cozzi & Carpita [2]. Monosaccharide composition was determined by CG after acid hydrolysis and reduction to acetylated alditols [2]. Extraction yield (% in dry weight basis) was 1.3 ±0.05 % and 19.8 ±0.4 % respectively for C. sinuosa and M. majors respectively. Neutral carbohydrates (anhydrous) and uronic acids represented a mass proportion of 55.4 ±0.6 and 9.3 ±1.2 respectively for C. sinuosa, and 70.8 ±1.7 and 8.5 ±0.8 respectively for M. major. Sulphate groups (expressed as SO3Na) represented a mass proportion of 14.3 ±1.2 and 24.4 ±3.3 respectively for C. sinuosa and M. major. Fucose was the main neutral sugar of both extracts, but in C. sinuosa the molar fraction was 46 ±2.8 while in M. major it was 82.2 ±7.8. Galactose, xylose, arabinose and manose represented 18.9,18.1,11.2 and 5.3 % of the neutral sugars in C. sinuosa extract, with only traces of glucose. Instead, glucose molar proportion in M. major extract was 13.6 % with 2.1 and 2 % of galactose and xylose respectively. Preliminary results suggest that M. major could be a suitable candidate for fucoidan production. Further studies are needed to elucidate chemical structure and composition, and to evaluate potential therapeutic properties.