Detoxification of the Lipid Peroxidation Aldehyde, 4-Hydroxynonenal, by Apple Phloretin In Vitro and in Mice

4-Hydroxy-2-nonenal (4-HNE) is asecondary cytotoxic product generatedfrom lipid peroxidation of polyunsaturated fatty acids (PUFAs). Theaccumulation of 4-HNE can covalently modify biomolecules, such asDNA and proteins, leading to various pathological conditions. Applephloretin has been shown to be able to trap 4-HNE in vitro, but the trapping mechanisms of 4-HNE by phloretin are not fullyunderstood. Moreover, whether the in vitro trappingefficacy of phloretin toward 4-HNE could be transferred into in vivo environments has never been investigated. In thepresent study, we observed the formation of 4-HNE conjugates of phloretinincreased as phloretin decreased during the in vitro incubation. We then purified and characterized three mono-4-HNE-conjugatesof phloretin using NMR and LC-MS/MS techniques. We thereafterdemonstrated that apple phloretin could scavenge in vivo 4-HNE via the formation of at least three mono-4-HNE-conjugatesof phloretin in a dose-dependent manner in mice after oral administrationof three doses of phloretin (25, 100, and 400 mg/kg). The findingsfrom this study pave the way to understanding how dihydrochalconescould act as effective scavengers of 4-HNE by working as sacrificialnucleophiles in vivo, thereby preventing or reducingthe risk of 4-HNE-associated chronic diseases.