Antioxidant activities of lignin-derived volatile phenolics in sesame oil – Relative superiority of 4-vinylguaiacol and its interactions with endogenous antioxidants

This study systematically investigated the antioxidant activities of seven lignin-derived volatile phenolics in sesame oil. Using in vitro assays and a purified sesame oil (PSO) model, 4-vinylguaiacol exhibited the strongest antioxidant capacity, followed by 4-ethylguaiacol, 4-methylphenol, and guaiacol, all of which outperformed vanillin, acetovanillone, and isoacetovanillone. The former four compounds effectively enhanced PSO stability, as evidenced by prolonged oxidation induction time, increased thermal decomposition temperature, and suppressed rise of various oxidation indices during accelerated storage. Quantum chemical calculations supported that 4-vinylguaiacol had the strongest antioxidant activity, consistent with experimental ranking. Binary interaction analysis revealed antagonism between 4-vinylguaiacol and sesamol, indicating that these two compounds should not be combined in antioxidant formulations, whereas additive effects were observed with γ -tocopherol. This study provides a theoretical basis for the rational design of antioxidant formulations. As natural antioxidants, 4-vinylguaiacol and its combination with γ -tocopherol show promising application prospects in commercial edible oil systems.