Antioxidant and Anti‐Pollution Effect of Naturally Occurring Carotenoids Astaxanthin and Crocin for Human Skin Protection

Four in vitro oxidative-stress models were used to study the antioxidant/antipollution effects of all-trans-astaxanthin and crocin compared to synthetic antioxidants. DPPH-scavenging activity of astaxanthin (5 mu M) was 2.4, 1.3, 1.4, 1.1 and 0.9-fold higher than that of alpha-tocopherol (AT), butylhydroxytoluene, butylhydroxyanisole, gallic acid and Trolox, respectively. Crocin scavenged the same radicals amount as butylhydroxytoluene and butylhydroxyanisole. Both carotenoids were more effective at reducing ferric ions than synthetic antioxidants and had a protective effect on the viability of stressed epidermal cells. Reactive oxygen species induced by hydrogen peroxide or cigarette smoke on a skin were quenched with astaxanthin and crocin to approximately the same extent as with AT. ASX was 3.8, 2.3 and 14-fold better singlet oxygen scavenger than Trolox, AT and gallic acid, respectively. The polyunsaturated fatty acids in the astaxanthin' emulsion were 6.5 and 2.5-fold more resistant to oxidation than in the control emulsion and the AT' emulsion, respectively.