Characterization of free fatty acids photo?oxidation under UV radiations: A stepwise Raman study

Lipid peroxidation (LPO) is an oxidative deterioration when oxidants such as reactive oxygen species attack lipids that contain double bonds especially polyunsaturated fatty acids (PUFAs). The mechanism of LPO composed three steps: initiation, propagation, and termination. It can result from several reaction pathways: (1) auto-oxidation, (2) enzymatic oxidation, or (3) photo-oxidation. UV solar exposition a major concern in skin research, dermatology, cosmetic science. Skin surface (SSLs) stratum corneum (SC) are among the first components exposed to external insults radiations. Fatty represent lipid class SSLs SC. aim this paper study photo-oxidation under radiations using Raman spectroscopy. Vibrational spectroscopies useful techniques follow its different stages oxidation: initiation step by following CH2/CH3 stretching bands ratio decreases due hydrogen abstraction alpha position; propagation where primary oxidation products formed hydroperoxides, which was evaluated 1165/1640 cm?1 ((?(OH) ?(C?O))/?(C?O)) increases during process; finally, termination marked formation aldehydes, alcohols, ketone, trans secondary products, others, monitored 1730/1640 (?(C?O) (ald.)/?(C?O) (acid)) ?(C?C)/cis ?(C?C) increase indicating products. To our knowledge, work put together spectral descriptors enabling follow, step, modifications free structures process.