Investigation of a green process for the polymerization of catechin

Flavonoids are polyphenolic secondary plant metabolites which possess antioxidant and anti-inflammatory properties. Besides, they have been shown to exhibit increased antioxidant properties in their polymerized form. Catechins are one of the attractive class of flavonoids which belong to the group of flavan-3-ols. Polymerization of catechins have been investigated in numerous studies indicating the requirement of certain amount of organic solvent to provide the solubility of the monomer. However, many research projects have been conducted recently to replace toxic organic contaminants of the processes with environmentally friendly solvents. In this aspect, deep eutectic solvents (DESs) that are regarded as "green solvents" have been studied extensively in various enzyme catalyzed reactions. In the present study, we focused on establishing a green pathway for laccase catalyzed polycatechin synthesis by replacing organic solvent content with DESs as green solvents. For this aim, various parameters were investigated, such as DES types and concentrations laccase amount and reaction time. Consequently, the highest molecular weight polycatechin was obtained using 5% (v/v) B-M, 125 U laccase in 1 hr of reaction time, at 30°C, as 4,354 ± 678 g mol^-1. Corresponding X/XO inhibitory activity and superoxide radical scavenging activities were achieved as, 59 and 50%, respectively.