New insights into the carbohydrate composition of the red alga Vertebrata lanosa

Vertebrata lanosa (L.) T.A. Christensen is a red alga commonly found at the North Atlantic coasts. Its extracts are applied as cosmetic ingredients [ 1 ], whereas the dried plant is consumed as spice in some regions of Europe. Previous phytochemical investigations revealed various secondary metabolites such as bromophenols, mycosporine-like amino acids or carotenoids [ 2 ], as well as agaran-type polysaccharides [ 3 ]. Unexpectedly, a high amount of carbohydrates was also found in a methanol-water (8:2) extract from V. lanosa , rich in sulfated bromophenols [ 4 ]. Aim of the current study was, therefore, to explore the chemical composition of these carbohydrates. Poly- and oligosaccharides were obtained from the water soluble partition of the crude aqueous methanolic extract by ethanol precipitation. The precipitate was analyzed by gel permeation chromatography, 13C-NMR and GC-QTOF-MS after hydrolysis. Dialyzed fractions were mainly composed of polysaccharides with molecular weights of 200 to 250 kDa. In line with previous findings, they mainly represented sulfated agar-type galactans (→[3)-β-d-Galp-(1→4)-α-l-Galp/-3,6-anhydro-Galp-(1→]n), containing glucose, xylose and arabinose as substituents. High amounts of glucose additionally suggested the presence of floridean starch. Interestingly, the monosaccharide composition varied significantly among samples collected at different time points. Also, fucose was tentatively identified by GC-MS as a further substituent. Apart from polysaccharides, fractions of lower molecular weight (≤5 kDa) were found to contain mannose as the predominant monomer, although mannans have rarely been described in the algal order Ceramiales. In summary, the current study provides new insights into the carbohydrate composition of the popular red alga V. lanosa . Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany