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SUMMARYThe aim of this study was to demonstrate that modification of the cellular redoxequilibrium occurs as a consequence of antioxidant nutrients intake (carotenoids, vitamine E and vitamine C) and that these nutrients play a role in the pigmentation of the skin without any UV exposure.We conducted a randomized, double-blind study in 20 healthy subjects to evaluate and to compare the efficacy of two mixtures of dietary antioxidants with regard to direct determination of melanin and carotenes by chromametry at selected skin sites and multiple reflection spectrometry from a 1 cm ~ region of skin of different parts of the body. Efficacy was assessed by a significant improvement of these parameters, in comparison with measurements performed on the day of randomization, before dietary supplement intake. The formulations per capsule of study dietary supplements are: 13 mg of 13-carotene, 2 mg of lycopene, 5 mg of vitamine E and 30 mg of vitamine C (B13/L2) or 3 mg of 13-carotene, 3 mg of lycopene, 5 mg of vitamine E and 30 mg of vitamine C (B3/L3).A 8-week B13/L2-supplementation lead to a detectable carotenodermia whereas the B3/L3-supplementation not.Signicative increase of melanin concentrations in skin were found after 4, 5, 6 and 8 weeks of dietary antioxidant intake in both groups (p<0.05). These results are discussed with regard to the redox control theory of melanocytes which regulates the tyrosinase activity.

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Papaverine 1 was oxidized by vanadium pentoxide in 2.5 M aqueous sulfuric acid media to give four new compounds: 4-hydroxy-6-demethylpapaveraldine (3), 4-hydroxy-4'-demethylpapaveraldine (4), 3-hydroxy-6-demethylpapaveraldine (5) and 3-hydroxy-4'-demethylpapaveraldine (6). The structures were established on the basis of mass spectrometry, ultraviolet-infrared spectrometry , nuclear magnetic resonance measurements and also chemical correlation with papaveraldine 2.

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