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Abstract: Background: High doses of sun-emitted UV-radiation induce reactive oxygen species (ROS) as major pro-oxidants thus inducing premature skin aging. The best prevention of the destructive action of free radicals in human skin is textile coverings, topical sunscreens and the development of a high antioxidative protective network. Objective: The effects of topical, systemic and combined application of antioxidants (AO) were investigated on human skin in vivo. Methods: Topical application of creams and systemic incorporation of tablets both containing AO was investigated in vivo by resonance Raman spectroscopy. Results: Topical, systemic and combined AO-treatments induced a statistically significant increase of AO levels in human skin while placebo did not show any changes. The highest accumulation was induced by the combination of topical and systemic AO. Carotenoid-tablets combined with placebo-cream induced less carotenoid accumulation than carotenoid-tablets alone. Carotenoid levelling after the end of treatment lasted for around 2weeks following the topical application of AOs, and up to 5weeks after systemic administration, depending on the BMI of volunteers. Conclusion: Topically applied AO are stored in the SC for a short time only due to the rapid AO-depletion by desquamation, textile contact, washing and environmental stress. In contrast to topical application, the systemically applied carotenoids are stored in the body fat tissue and slowly released onto the skin surface with sweat and sebum. The combined topical and systemic application of AO represents an optimal form of protection of the AO-network. [Copyright &y& Elsevier]

Abstract: Carotenoids, naturally occurring lipophilic micronutrients, possess an antioxidant activity associated with protection from damage induced by free radicals. The present study investigated an innovative non-invasive method to measure cutaneous levels of lycopene and β-carotene and to monitor the distribution of orally administered lactolycopene in human skin and plasma. A double-blind placebo-controlled randomized study was performed in 25 volunteers, who were under a lycopene-deprived diet (4weeks prior to study until end of the study) and orally received either lactolycopene or placebo for 12weeks. Skin and plasma levels of lycopene and β-carotene were monitored monthly using Raman spectroscopy and HPLC, respectively. Cutaneous levels of lycopene and β-carotene monitored by resonance Raman spectroscopy showed high reliability. Irrespective of the investigated area, cutaneous levels were sensitive to lycopene deprivation and to oral supplementation; the forehead showed the closest correlation to lycopene variation in plasma. Plasma and skin levels of lycopene were both sensitive to oral intake of lactolycopene and, interestingly, also skin levels of β-carotene. Thus, oral supplementation with lycopene led to an enrichment of β-carotene in human skin, possibly due to the fact that carotenoids act in the skin as protection chains, with a natural protection against free radicals. [Copyright &y& Elsevier]

Abstract: Antioxidant substances in the skin are expected to slow down photo ageing. We therefore developed the hypothesis that high levels of antioxidant substances may be correlated to lower levels of skin roughness. By utilizing modern optical non-invasive in vivo methods, the structures of the furrows and wrinkles as well as the concentration of lycopene were analyzed quantitatively on the forehead skin of 20 volunteers aged between 40 and 50 years. In a first step, the age of the volunteers was correlated to their skin roughness. Here, no significant correlation was found. In a second step, a significant correlation was obtained between the skin roughness and the lycopene concentration (R =0.843). These findings indicate that higher levels of antioxidants in the skin effectively lead to lower levels of skin roughness, and therefore support our hypothesis. [Copyright &y& Elsevier]