DYNAMICS OF THE PHENOLIC CONSTITUENTS AND ANTIOXIDANT ACTIVITY IN SUBMERGED CULTURES OF Xylaria SPECIES

Abstract

Purpose. This study was conducted to enhance comprehension of the dynamic process of synthesis of phenolic compounds by representatives of the genus Xylaria, and the correlation between phenol content and antioxidant properties found in biomass and culture liquid during submerged cultivation. Methods. Cultivation of Xylaria polymorpha and Xylaria longipes fungal strains from the IBK Mushroom Culture Collection was carried out on a glucose-yeast-peptone nutrient medium under submerged conditions. Harvesting of both biomass and culture liquid was done on the 3rd, 5th, 7th, and 9th day of cultivation, followed by extraction with ethyl acetate. The total phenol content of extracts was determined using the Folin–Ciocalteu method and the antioxidant potential was evaluated through the DPPH assay. Results. Findings revealed that the accumulation of phenolic compounds by fungal species of the Xylaria genus was specified on a strain level. Notably, X. longipes strains exhibited higher production of phenolic constituents compared to X. polymorpha and demonstrated superior antioxidant activity at a specific time of cultivation. Furthermore, a strong correlation was established between the dynamics of polyphenol accumulation and antioxidant activity in both mycelial biomass and culture liquid. Conclusions. Natural phenolic compounds with antioxidant properties were extracted from the biomass and culture liquid of the studied strains. Significantly higher concentrations of phenolic compounds and values of antioxidant activity were found in the biomass compared to the culture liquid. The results indicate that a later day of cultivation is not necessarily equivalent to the production of more phenols, emphasizing the need for a comprehensive assessment of the accumulation of these compounds and the dynamic study of related parameters.