Vitamin C prevents myricetin degradation in boiling water by reducing ortho-quinone intermediates

Myricetin, a bioactive flavonoid, degrades rapidly in boiling water, limiting its use in functional foods and pharmaceuticals. This study explores the protective effect of vitamin C on the thermal degradation of myricetin and its mechanism of action. O-phenylenediamine derivatization identified reactive ortho-quinone intermediates, while density functional theory (DFT) calculations (ΔG = -47.74 kcal/mol) confirmed the redox mechanism. Vitamin C significantly improved myricetin retention from 32.8 % to 91.4 % in 0.8 mM after 100 min of heating, outperforming nitrogen treatment. Myricetin degradation begins with oxidation to ortho-quinones, which further degrades into phenolic acids and aldehydes. Vitamin C not only inhibited this process but also reversed oxidation by reducing ortho-quinones back to myricetin. These findings highlight vitamin C's potential to enhance flavonoid stability and bioavailability in functional heat-processed foods.