Hydrolyzed Conchiolin Protein (HCP) Extracted from Pearls Antagonizes both ET-1 and α-MSH for Skin Whitening.

Pearl powder is a famous traditional Chinese medicine that has a long history in treating palpitations, insomnia, convulsions, epilepsy, ulcers, and skin lightining. Recently, several studies have demonstrated the effects of pearl extracts on protection of ultraviolet A (UVA) induced irritation on human skin fibroblasts and inhibition of melanin genesis on B16F10 mouse melanoma cells. To further explore the effect we focused on the whitening efficacy of pearl hydrolyzed conchiolin protein (HCP) on human melanoma MNT-1 cells under the irritation of alpha-melanocyte-stimulating hormone (α-MSH) or endothelin 1 (ET-1) to evaluate the intracellular tyrosinase and melanin contents, as well as the expression levels of tyrosinase (TYR), tyrosinase related protein 1 (TRP-1), and dopachrome tautomerase (DCT) genes and related proteins. We found that HCP could decrease the intracellular melanin content by reducing the activity of intracellular tyrosinase and inhibiting the expression of TYR, TRP-1, DCT genes and proteins. At the same time, the effect of HCP on melanosome transfer effect was also investigated in the co-culture system of immortalized human keratinocyte HaCaT cells with MNT-1. The result indicated that HCP could promote the transfer of melanosomes in MNT-1 melanocytes to HaCaT cells, which might accelerate the skin whitening process by quickly transferring and metabolizing melanosomes during keratinocyte differentiation. Further study is needed to explore the mechanism of melanosome transfer with depigmentation.

Explorating the mechanism of Huangqin Tang against skin lipid accumulation through network pharmacology and experimental validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Huangqin Tang (HQT), a famous prescription with the effect of clearing pathogenic heat and detoxifying, was first recorded in "Treatise on Typhoid and Miscellaneous Diseases". It has proved that HQT has good anti-inflammatory and antioxidant effects and can improve acne symptoms clinically. However, the study on the regulation of HQT on sebum secretion which is one of the inducements of acne is not enough. AIM OF THE STUDY: This paper aimed to investigate the mechanisms of HQT in the treatment of skin lipid accumulation by network pharmacology and validating the results via in vitro experiments. MATERIALS AND METHODS: Network pharmacology was employed to predict the potential targets of HQT against sebum accumulation. Then, the palmitic acid (PA)-induced SZ95 cell model was established to evaluate the effect of HQT on lipid accumulation and anti-inflammation, and the core pathways predicted by network pharmacology were verified in cell studies. RESULTS: 336 chemical compounds and 368 targets in HQT were obtained by network pharmacology, of which 65 targets were related to sebum synthesis. 12 core genes were revealed by protein-protein interaction (PPI) network analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results suggested that AMP-activated protein kinase (AMPK) signaling pathway might play a crucial role in regulating lipogenesis. In vitro experiments, HQT suppressed lipid accumulation, downregulated the expressions of sterol-regulatory element binding protein-1 (SREBP-1) and fatty acid synthase (FAS), and upregulated AMPK phosphorylation. Furthermore, AMPK inhibitor reversed HQT-mediated sebosuppressive effect. CONCLUSION: The results disclosed that HQT ameliorates lipogenesis in PA-induced SZ95 sebocytes partially through the AMPK signaling pathway.