Elaboration and validation of methods for quantitative analysis of phenolic compounds and flavonoids in the extracts of higher fungi

Abstract

Simple express methods for the quantitative evaluation of phenolic compounds and flavonoids in the extracts of basidiomycetes and plants were developed using ethanol extracts of the Fomes fomentarius xylotrophic fungus as a model system. The analysis of phenolic compounds was based on the photocolorimetric Folin–Ciocalteu method. The spectrophotometric method based on the reaction of complex formation with aluminum chloride was chosen for the analysis of flavonoids. The composition of the reactants and their concentrations in the reaction mixtures were optimized for both techniques. The advantages of the developed techniques were the following: the simplicity, speed, the use of commonly used laboratory equipment, and the small volumes of the test samples and reagents. The proposed methods allow for serial analyses of up to four dozen samples. It was found that the decrease of the volume of the studied sample by factors of 5–10 did not reduce the sensitivity of the techniques in comparison with the classic versions of the methods. The proposed methods were examined for linearity, accuracy, repeatability, and convergence. The validation showed that the methods meet the eligibility criteria. The proposed methods for the quantitative analysis of phenolic compounds and flavonoids can be recommended for the characterization of fungi and plant extracts of both natural and biotechnological origin.