Artocarpus altilis heartwood extract protects skin against UVB in vitro and in vivo

Abstract

Ethnopharmacological relevanceArtocarpus altilis (Moreceae) has been widely used as a traditional folk medicine in Southeast Asia for the treatment of many diseases, including skin disorders, such as ulcers and dermatitis. Aim of the studyThe present study aimed to investigate the ability of an artocarpin-enriched extract to prevent ultraviolet radiation B-induced photodamage. Materials and methodsThe content of artocarpin in the extract was determined by high performance liquid chromatography (HPLC). A DPPH assay was used to evaluate the free radical scavenging activity of the extract, which was compared with those of l-ascorbic acid and α-tocopherol. Cytotoxicity and proliferation of cells treated with the extract were determined using XTT and BrdU assays, respectively. Human skin fibroblasts and keratinocytes were pretreated with the extract for 24h and later irradiated with ultraviolet radiation B at 128J/cm2. The levels of TNF-α and IL-6 released from ultraviolet radiation B-irradiated keratinocytes and, MMP-1 and type-I procollagen produced by ultraviolet radiation B-irradiated fibroblasts were measured by ELISA and/or western blotting. The hairless skin of male mice (outbred ICR) was treated with the extract or l-ascorbic acid solution prior to exposure to ultraviolet radiation B irradiation. The dose of ultraviolet B irradiation was consecutively increased to 18, 36, 54, and 72J/cm2 at weeks 1–4, 4–7, 7–10, and 10–12, respectively. The epidermal thickness and collagen content in the skin of ultraviolet radiation B-irradiated mice were evaluated. ResultsThe extract concentration of 50µg/mL was not toxic and did not inhibit the proliferation of fibroblasts. The pretreatment of fibroblasts with 50µg/mL extract prior to ultraviolet radiation B irradiation attenuated MMP-1 production but did not affect type-I procollagen production. The extract also decreased the ultraviolet radiation B-induced production of TNF-α and IL-6 in keratinocytes. Moreover, the topical administration of the extract suppressed epidermal thickening and collagen loss in chronically ultraviolet radiation B-exposed skin in mice. ConclusionsThe experimental study revealed that A. altilis extract suppresses structural alterations in skin damaged by ultraviolet radiation B irradiation. This suppression was, at least partially, mediated by decrease in MMP-1 production in fibroblasts and TNF-α and IL-6 productions in keratinocytes.