Molecular design for physiologically active compounds from lignin by oxidative degradation

Abstract

  It is important that lignin convert to high value-added product for effective utilization. It is said that lignin has little physiologically activity, although the various polyphenols of similar structure to lignin, for example lignans, flavonoids, stilbene, have various physiologically activity. In this study the physiologically active compounds molecularly designed from lignin based on structure of high activity polyphenols. The objective structure characteristic of lignin derivatives is as follows. 1) Phenolation of lignin with 1,2-dihydroxy aromatic derivatives, 2) Conversion of native lignin to β-O-4 type lignin, 3) Control of molecular weight (Mw1000-3000), 4) Conversion to long conjugate structure. o-Dihydroxy phenolation and conversion of native lignin to β-O-4 type lignin were achieved by phase separation system with catechol. Control of molecular weight of lignin derivatives and induction of long conjugate structure were occurred by alkaline cupric (CuO) oxidative degradation. The structure characteristic of lignin derivatives through the these treatment were analyzed by PDA-GPC, LC-MS and FT-IR. The antioxidative activity of lignin derivatives were largely similar to catechin in spite of polymer, extremely useful as physiologically active compounds from lignin.