Evaluation of a sunscreen photoprotective effect by ascorbic acid assessment in human dermis using microdialysis and gas chromatography mass spectrometry

Abstract

Ultraviolet irradiation causes adverse effects like sunburn, photosensitivity reactions or immunologic suppression. The aim of this study was to evaluate the photo-protective outcome of a sunscreen cream (SPF8) by the determination of erythema indexes and the assessment of ascorbic acid and its metabolites in human dermis. These substances were used as markers of oxidative effect. Eight healthy female subjects were enrolled in this study. Two abdominal areas were exposed to solar simulated irradiation with three minimal erythema dose, one with SPF8 application and the other site without SPF8 application. Two other areas were used as control, one without SPF8 application and the other site after SPF8 application. Ascorbic acid and its metabolites (dehydroascorbic acid, threonic acid, oxalic acid and xylose) were collected from human dermis by microdialysis and assessed by gas chromatography mass spectrometry. Irradiated site without sunscreen application had significantly demonstrated lower dermis ascorbic acid concentrations and a higher erythema index than the three other sites (P < 0.05). Threonic acid, oxalic acid and xylose dermis concentrations were significantly higher in site III than in the control site I (P < 0.05). The protected-irradiated site did not show erythema formation and there was stability of ascorbic acid dermis concentrations with non-variation in its metabolites. The assessment of ascorbic acid and its metabolites in human dermis could be an efficient tool to demonstrate the oxidative process and consequently to control the efficiency of sunscreen creams against undesirable UV effects.

Acute ascorbate supplementation alone or combined with arginase inhibition augments reflex cutaneous vasodilation in aged human skin

“…We did not directly show that the dose of Asc delivered to the cutaneous vasculature through microdialysis reduced oxidative stress in aged skin. However, the dose of Asc utilized in this study was more than double compared with studies where topical administration of an 8.0% Asc solution decreased markers of oxidative stress in human skin (22,23). Moreover, topical administration of this dose reached peak concentration and demonstrated effective antioxidant capabilities within 1 h of administration.…”

“…Moreover, in human skin, topical administration of 3-8% Asc solutions reduces oxidant stress associated with aging (19,31) and induced by exposure to ultaviolet irradiation (7,22). Therefore, the aim of this study was to determine the effect of acute Asc administration in attenuated reflex cutaneous vasodilation in aged skin.…”

Vitamin C, Aged Skin, Skin Health

“…Vitamin C protects keratinocytes from the damage produced by ultraviolet A [36]. Vitamin C transport proteins are increased in keratinocytes in response to UV light, suggesting an increased need for vitamin C uptake for adequate protection [37,38]. UV light decreases vitamin C content of skin, an effect that is dependent on the intensity and duration of UV exposure [39][40][41][42].…”

“…UV light decreases vitamin C content of skin, an effect that is dependent on the intensity and duration of UV exposure [39][40][41][42]. In cultured keratinocytes, the addition of vitamin C reduces UV-related DNA damage and lipid peroxidation, limits the release of pro-inflammatory cytokines, and protects against apoptosis [36][37][38][39][40][41][42]. Vitamin C also modulates redox-sensitive cell signaling in cultured skin cells and consequently increases cell survival following UV exposure [43,44].…”

Ex vivo Cutaneous Absorption Assessmentof a Stabilized Ascorbic Acid Formulation Using a Microdialysis System

“…It can be severely depleted after UV irradiation [8], and only a very small portion of Asc ingested penetrates into the skin [9]. Continuous large oral doses of Asc can cause gastrointestinal discomfort and diarrhea.…”