Preparation and Anti-Lung Cancer Activity Analysis of Guaiacyl-Type Dehydrogenation Polymer

In this paper, guaiacyl dehydrogenated lignin polymer (G-DHP) was synthesized using coniferin as a substrate in the presence of β-glucosidase and laccase. Carbon-13 nuclear magnetic resonance ((13)C-NMR) determination revealed that the structure of G-DHP was relatively similar to that of ginkgo milled wood lignin (MWL), with both containing β-O-4, β-5, β-1, β-β, and 5-5 substructures. G-DHP fractions with different molecular weights were obtained by classification with different polar solvents. The bioactivity assay indicated that the ether-soluble fraction (DC(2)) showed the strongest inhibition of A549 lung cancer cells, with an IC(50) of 181.46 ± 28.01 μg/mL. The DC(2) fraction was further purified using medium-pressure liquid chromatography. Anti-cancer analysis revealed that the D(4) and D(5) compounds from DC(2) had better anti-tumor activity, with IC(50) values of 61.54 ± 17.10 μg/mL and 28.61 ± 8.52 μg/mL, respectively. Heating electrospray ionization tandem mass spectrometry (HESI-MS) results showed that both the D(4) and D(5) were β-5-linked dimers of coniferyl aldehyde, and the (13)C-NMR and (1)H-NMR analyses confirmed the structure of the D(5). Together, these results indicate that the presence of an aldehyde group on the side chain of the phenylpropane unit of G-DHP enhances its anticancer activity.