Topological structure and antioxidant properties of macromolecules of lignin of hogweed Heracleum sosnowskyi Manden

Abstract This article presents the study of topological and chemical structure of lignin macromolecules isolated from stems of hogweed Heracleum sosnowskyi Manden. The chemical structure was characterized by 13C and 2D NMR-spectroscopy, chemical analysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The methods of sedimentation-diffusion analysis and capillary viscometry were used to study the hydrodynamic properties of macromolecules in solutions and to reveal the features of the topological structure. The molecular mass of the fractions, the macromolecular radii and the hydrodynamic invariants were determined. The analysis of the scaling dependences within the framework of Mark-Kuhn-Houwink equation was performed. The obtained results showed that the behavior of hogweed lignin macromolecules corresponded to high-molecular weight compounds with chaotically branched topological structure. It was determined that the hogweed lignin had high antioxidant activity comparable to that of recognized antioxidants. The sorption properties of several lignins were studied and the significant adsorption capacity to T-2 mycotoxin and naturally occurring long-lived thorium radionuclide (Th232) was determined.