Physicochemical properties and antioxidant activity of melanin fractions from inonotus obliquus sclerotia

摘要

Six pigment fractions (total yield 52.13% of raw material mass) were isolated by fractionation of polymeric components of melanin from Inonotus obliquus (Pers.) Pil. sclerotia. The isolated fractions differed in degree of aromaticity, molecular-weight distribution, and content of functional groups according to elemental analysis; UV, IR, and 13C NMR spectroscopy; and gel chromatography. The dominant components were highly aromatic polymers of molecular weight 2-20 kDa with a high content of carboxylic and phenolic hydroxyls. It was found that fractions with a high degree of aromaticity and content of pyrocatechol groups exhibited pronounced antioxidant activity.