Highly Efficient Bioconversion of trans-Resveratrol to δ-Viniferin Using Conditioned Medium of Grapevine Callus Suspension Cultures

Abstract

δ-Viniferin is a resveratrol dimer that possesses potent antioxidant properties and has attracted attention as an ingredient for cosmetic and nutraceutical products. Enzymatic bioconversion and plant callus and cell suspension cultures can be used to produce stilbenes such as resveratrol and viniferin. Here, δ-viniferin was produced by bioconversion from trans-resveratrol using conditioned medium (CM) of grapevine (Vitis labruscana) callus suspension cultures. The CM converted trans-resveratrol to δ-viniferin immediately after addition of hydrogen peroxide (H2O2). Peroxidase activity and bioconversion efficiency in CM increased with increasing culture time. Optimized δ-viniferin production conditions were determined regarding H2O2 concentration, incubation time, temperature, and pH. Maximum bioconversion efficiency reached 64% under the optimized conditions (pH 6.0, 60 °C, 30 min incubation time, 6.8 mM H2O2). In addition, in vitro bioconversion of trans-resveratrol was investigated using CM of different callus suspension cultures, showing that addition of trans-resveratrol and H2O2 to the CM led to production of δ-viniferin via extracellular peroxidase-mediated oxidative coupling of two molecules of trans-resveratrol. We thus propose a simple and low-cost method of δ-viniferin production from trans-resveratrol using CM of plant callus suspension cultures, which may constitute an alternative approach for in vitro bioconversion of valuable molecules.

Study of phenoxy radical couplings using the enzymatic secretome of Botrytis cinerea

“…For example, in the case of resveratrol, the pioneering work of Langkage and Pryce ( Langcake and Pryce, 1977 ) showed that the main compound obtained was trans -δ-viniferin, derived from a C-8/C-3′ dimerisation using horseradish peroxidase. These results have since been observed in numerous studies on laccases and peroxidases ( Wilkens et al, 2010 ; Gindro et al, 2017 ; Righi et al, 2020 ; Huber et al, 2022a ; Park et al, 2022 ). This point could be explained by the fact that the presence of an exocyclic conjugated double bond increases the delocalization of the radical and thus its stability.…”

Linkage and Stereochemistry Characters of Phenolic Antioxidant Product Formation

“…The α,β diastereoselectivity could also be found in natural phytophenol oligomers. This is because that phytophenol oligomerization is essentially a process of phytophenol interacting with free radical, under the condition of oxidase catalysis . Thus, it quite resembles antioxidant product formation.…”

“…This is because that phytophenol oligomerization is essentially a process of phytophenol interacting with free radical, under the condition of oxidase catalysis. 30 Thus, it quite resembles antioxidant product formation. However, as seen in SI 17, there was no pair of epimers among 40 phytophenol oligomers, despite each of them has two chiral atoms and should possess 4 possible stereoisomers.…”