Spectroscopic analysis of a sulfur-rich sugar extract of the bioactive fucoidan from the brown alga Sargassum vulgare

Abstract

This research deals with a qualitative study, using Fourier transform infrared technology, of some biologically active sugar extract rich in fucoidan in the brown algae Sargassum vulgare. Samples were collected in the spring of 2023 from the Higher Studies area on the beach of the city of Latakia, and the extraction process was carried out with hot water using an ultrasound device.

The infrared spectrum (FT-IR) of the sugar extract confirmed that it contains fucoidan, as sulfur groups appeared in the spectrum, as did hydroxyl groups common in all types of sugars, and also the carboxyl group of uronic acid, which is one of the monomers that make up the fucoidan polymer, with wave numbers indicating to the presence of the C-H bond belonging to the following monosaccharides: fucose, glucose, mannose, and xylose.

The spectrum also indicated the presence of proteins, as the wave number appeared at 1700 , which indicates the bond stretching vibration (C=O), which is particularly due to the peptide bond. The wave number also appeared at 1282 confirming an asymmetric vibration of the bond (O=S=O) present in the sulfate ester group, as the percentage of organic sulfates belonging to fucoidan reached The sugar content reached 23.06%. The yield of calcium alginate was 2.424%, and the yield of the pure sugar extract of alginate rich in fucoidan was 1.75%.