Redox behaviour of resveratrol in the presence of Cu(2+) and tebuconazole Resveratrol, an antioxidant naturally occurring in wine grapes, is thought to have a preventive biological activity against a number of diseases. However, it has been recently shown that in the presence of metal ions, such as Cu2+, resveratrol forms oxidative radicals. Cu2+ is usually present in wine due to former usage of bluestone in vineyards. Fungicide tebuconazole has substituted bluestone and is presently one of the most widely used agrochemicals in wine industry; wine thus may contain traces of tebuconazole.
A research project studied the ternary system of resveratrol, Cu2+, and tebuconazole experimentally and theoretically (using mass spectrometry, antioxidant capacity assay and quantum-chemical calculations) to model the redox behaviour of resveratrol in wine. The results ishow that tebuconazole prevents formation of oxidative resveratrol radicals (induced by Cu2+ reaction with resveratrol) via preferential Cu2+ capture and protection of the binding sites of resveratrol. The authors comment that this positive effect of tebuconazole has not been observed before.
Source: Does resveratrol retain its antioxidative properties in wine? Redox behaviour of resveratrol in the presence of Cu(II) and tebuconazole. Jaklová Dytrtová J, Straka M, B?lonožníková K, Jakl M, Ryšlavá H. Food Chem. 2018 Oct 1;262:221-225.