Supplementing collagen is considered to contribute to delaying skin aging. In this work, we developed a novel combination for improving skin aging by stimulating the biosynthesis of collagen. By screening a library of Chinese herbal medicines (CHM), we found that Angelicae Dahuricae Radix (Baizhi), Lilii bulbus (Baihe), Glycyrrhizae radix et rhizoma (Gancao), and Jujubae fructus (Dazao) substantially increased the mRNA expression levels of type Ⅰ collagen, suggesting their potential anti-skin-aging activity. To keep the structural integrity of collagen, prolyl 4-hydroxylase (P4H), a key enzyme in collagen synthesis, was recombinantly expressed in Escherichia coli. In addition, the transfersome with added P-4H was prepared to improve the transdermal absorption of combination. Vitamin C (VC), the substrate required for the activity of P4H, was also incorporated into the combination. Eventually, an optimal combination, consisting of Baizhi, Baihe, Gancao, P4H transfersome and VC, was obtained by a series of combination experiments. Based on traditional CHM and modern biological agents, we developed a novel combination against skin aging by promoting the synthesis of collagen. Collectively, the combination show the high potential of application to delay skin aging.

Photoaging is the premature aging of skin caused by long-term exposure to ultraviolet radiation. The skin mucus of Andrias davidianus has anti-photoaging activity, but its active ingredients and mechanisms are not clear. In this study, we first investigated the photoprotective effect of enzymatic hydrolysates from Andrias davidianus mucus (AD-APRO) on UVA-irradiated responses in human skin fibroblasts (HSF) cells and mice. AD-APRO hindered the UVA induced activation of reactive oxygen species (ROS) and increased the activity of antioxidase in HSF cells. Furthermore, topical application of AD-APRO ameliorated skin photoaging in a mouse model by suppressing oxidative stress. CAMP and Peptide Ranker, two online tools, were used to predict the active peptides of AD-APRO against photoaging. The active peptides of AD-APRO were predicted to be KDACCNLVLHFNPRF, NLVLHFNPRF, FEWKP, and CNLVLHFNPRF. These results provide a basis for the study of the photoprotective effect of AD-APRO and suggest that it can be potentially used as an agent against UVA-induced skin photoaging in humans.