Anti‐skin aging properties of protocatechuic acid in vitro and in vivo

BACKGROUND: Protocatechuic acid has reported containing antioxidant effects. However, information on its other biological activities such as anti-wrinkle properties is limited AIMS: The objective of this study was to evaluate an antioxidant, collagen synthesis, MMP-1 inhibition (in vitro), and anti-wrinkle (in vivo) effects of protocatechuic acid (PCA) as a potent ingredient for wrinkle-care cosmetic. METHODS: Antioxidant effect was evaluated based on its scavenging activity for free radicals (DPPH, ABTS+). To evaluate the anti-skin aging potency of PCA, levels of MMP-1 and type I procollagen were measured using an ELISA kit in cultured human dermal fibroblasts. To further investigate if PCA could increase collagen synthesis, full-thickness human skin explants were immunostained with an anti-collagen I antibody. In an in vivo study, 22 female subjects were enrolled in a placebo-controlled trial. Facial wrinkle, especially crow's feet around eyes, was treated with lotion-containing 0.02% PCA for 8 weeks and compared with the placebo. RESULTS: In in vitro study, PCA showed high antioxidant activ ity. PCA also showed potential to induce the synthesis of type I collagen in human dermal fibroblast and skin explants. It inhibited MMP-1 secretion from UVA-irradiated human dermal fibroblast. An in vivo study, treatment with lotion-containing 0.02% PCA for 8 weeks significantly reduced the percentage of all skin wrinkle parameters. CONCLUSION: Based on the results of in vitro assays and in vivo skin testing in human subjects, PCA shows potential in anti-wrinkle or anti-skin aging treatments.