Artocarpin-enriched extract reverses collagen metabolism in UV-exposed fibroblasts

In previous studies, the Artocarpus incisus extract containing 45% w/w artocarpin showed activities of antioxidation, antimelanogenesis and restoration of wrinkled-skin fibroblasts. Here, extract containing 90% w/w artocarpin was tested for its antioxidant activity and in ultraviolet (UV) A-irradiated fibroblasts, its ability to restore type I collagen and inhibit matrix metalloproteinase-1 (MMP-1) elevation. This extract was a less effective antioxidant of EC50 of 116.0 ± 5.1 μg/mL than L-ascorbic acid (9.7 ± 0.01 μg/mL). The extract (0.625–50 μg/mL) showed no cytotoxicity toward primary human skin fibroblasts. MMP-1 was markedly elevated at 72 h after UVA irradiation compared to non-irradiation cells (p < 0.01). This UVA-induced elevation was inhibited by 50 μg/mL extract or 50 ng/mL all-trans retinoic acid. In an aged and sun-exposed skin tissue culture model, the increase of epidermal thickness in the 250 μg/mL artocarpin-enriched extract or 75 μg/mL all-trans retinoic acid-treated group when compared to the non-treated group was markedly observed since day 1 of treatment. Moreover, the extract or all-trans retinoic acid-treated groups exhibited higher density of immunofluorescence staining of type I collagen than non-treated group. This coincides with significantly higher (p < 0.05) collagen content, as indicated by measuring hydroxyproline. Our results firstly revealed that the artocarpin-enriched extract reversed the activities of UVA-irradiated fibroblasts and improved the type I collagen deposition in aged/photoaged skin.