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 beta-glucosidase and laccase. Carbon-13 nuclear magnetic resonance (C-13-NMR) determination revealed that the structure of G-DHP was relatively similar to that of ginkgo milled wood lignin (MWL), with both containing beta-O-4, beta-5, beta-1, beta-beta, 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 (DC2) showed the strongest inhibition of A549 lung cancer cells, with an IC50 of 181.46 +/- 28.01 mu g/mL. The DC2 fraction was further purified using medium-pressure liquid chromatography. Anti-cancer analysis revealed that the D-4 and D-5 compounds from DC2 had better anti-tumor activity, with IC50 values of 61.54 +/- 17.10 mu g/mL and 28.61 +/- 8.52 mu g/mL, respectively. Heating electrospray ionization tandem mass spectrometry (HESI-MS) results showed that both the D-4 and D-5 were beta-5-linked dimers of coniferyl aldehyde, and the C-13-NMR and H-1-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.