Preparation and Bioactivities of Lignin-based Polyphenols

Aiming at the problems of low active sites and poor activity of lignin, pyrogallol modified enzymatic hydrolyzed lignin(PEHL), a lignin-based polyphenol compound, was prepared by one-pot demethylation and phenolic modification from acidic molten salt hydrate. The experimental results demonstrated a significant increase in the reaction sites of demethylated enzymatic hydrolyzed lignin(DEHL) and PEHL, with phenolic hydroxyl groups increasing from 1.25 mmol/g in raw enzymatic hydrolyzed lignin(EHL) to 3.49 and 5.70 mmol/g, respectively. Furthermore, DPPH · scavenging experiments revealed a significant enhancement in the antioxidant activities of lignin-based polyphenol compounds, and the DPPH · scavenging rates of DEHL and PEHL increased by 46.9% and 64.4%, respectively. Moreover, PEHL showed promising antibacterial activity, and low cytotoxicity with inhibition rates of E. coli and S. aureus by 85.22% and 99.76%, respectively.