Qualitative and quantitative composition of protective phenolic compounds in aqueous and aqueous-ethanol extract of brown algae of the genus Cystoseira

Introduction. Herbal medicines are used in medical practice to treat a wide range of diseases. Marine organisms, especially brown algae, have attracted great interest worldwide due to their potential use in various fields of medicine. Algae are considered to be a rich storehouse of bioactive compounds such as sulfated polysaccharides, carotenoids, phytosterols, phycobiliproteins, phloroglucin, etc. The presence of polysaccharides such as alginate, laminarin and sulfated fucoidan, etc., makes them more significant compared to other algae. Recently, there has been an increasing trend among researchers to use algae as a source of natural antioxidants.

The aim of the study was to evaluate the qualitative and quantitative composition of phenolic compounds in the aqueous and aqueous-ethanol extract of brown algae of the genus Cystoseira barbata, collected on the shelf of the eastern coast of Crimea in the summer, as well as to evaluate their antiradical properties.

Material and methods. To obtain an extract of phenolic compounds, a sample of frozen brown algae of the genus Cystoseira barbata, collected in July 2022 in the bays of the eastern coast of Crimea, was dried to a constant mass at a temperature of 100–105 ⁰C. Phenolic compounds from a sample of dry raw materials were extracted by the method of digitization. Water and 70% ethyl alcohol were used as solvents. A qualitative and quantitative analysis of the extracts was performed, as well as an assessment of their antiradical properties.

Results. The presence of tannins was assumed in the obtained extracts by qualitative analysis. By the methods UV- and IR-spectroscopy have confirmed this assumption. It has been established that water extracts contain a higher amount of phenolic compounds, however, water-ethanol extracts have a higher antiradical activity. The resulting discrepancy can be explained by the presence in the alcohol extract of compounds belonging to the class of xanthines, which may also have antiradical properties. It is possible that the antioxidant effect of alcohol extracts have a synergistic effect, however, this assumption requires additional research.

Conclusion. Thus, our data open up broad prospects for further study of brown algae of the genus Cystoseira barbata, growing on the Black Sea coast, as a source of biologically active compounds of the phenolic and xanthine series. These groups of compounds are of interest to the pharmaceutical industry as protectors of slowing down the aging process, preventing age-related diseases, and having a protective effect on the ischemic zone.