Aerobic oxidation behavior of α-ionone catalyzed by N-hydroxyphthalimide combined with acetylacetone cobalt(Ⅱ)

A practical catalytic method to oxidize α-ionone with molecular oxygen using N-hydroxyphthalimide(NHPI)combined with acetylacetone cobatt(Ⅱ)(Co(acac)2)was developed,and the probable catalytic mechanism was proposed.The influences of the reaction conditions on conversion of α-ionone and the selectivity of the major product(5-keto-α-ionone)were investigated,and the technical parameters for 5-keto-α-ionone were optimized.The results show that the primary product is 5-keto-α-ionone,and by-products include epoxy-α-ionone,as well as rearrangement products 4-keto-β-ionone and epoxy-β-ionone,which are characterized by infrared spectra,proton nuclear magnetic resonance spectra,mass spectra and elemental analysis.The selectivity of 5-keto-α-ionone and the conversion of α-ionone are 55.0% and 97.0%,respectively,when 30%(molar fraction)NHPI,1.0%(molar fraction)Co(acac)2 and no solvent are employed under O2 pressure of 1.0 MPa and the reaction temperature of 65℃for 11 h.The procedure shows good reproducibility in the parallel experiments.

α-Ionone protects against UVB-induced photoaging in epidermal keratinocytes

Objective: To evaluate whether α-ionone, an aromatic compound mainly found in raspberries, carrots,roasted almonds, fruits, and herbs, inhibits UVB-mediated photoaging and barrier dysfunction in a human epidermal keratinocyte cell line(HaCaT cells).Methods: The anti-photoaging effect of α-ionone was evaluated by detecting the expression of barrierrelated genes and matrix metalloproteinases(MMPs) in HaCaT cells. The levels of reactive oxygen species,oxidation product, antioxidant enzyme, and inflammatory factors were further analysed to underline the protective effect of α-ionone on epidermal photoaging.Results: It was found that α-ionone attenuated UVB-induced barrier dysfunction by reversing keratin 1and filaggrin in HaCaT cells. α-Ionone also reduced the protein amount of MMP-1 and mRNA expression of MMP-1 and MMP-3 in UVB-irradiated HaCaT cells, implying protective effects on extracellular matrix.Furthermore, HaCaT cells exposed to α-ionone showed significant decreases in interleukin(IL)-1β, IL-6,IL-8, and tumor necrosis factor-α as compared to UVB-irradiated HaCaT cells. α-Ionone treatment significantly inhibited the UVB-induced intracellular reactive oxygen species increase and malondialdehyde accumulation. Therefore, the beneficial effects of α-ionone on inhibiting MMPs secretion and barrier damage may be related to attenuated inflammation and oxidative stress.Conclusion: Our results highlight the protective effects of α-ionone on epidermal photoaging and promote its clinic application as a potential natural anti-photodamage agent in future.