Tyrosinase is a key enzyme in melanin biosynthesis. Activators of tyrosinase with stimulatory effects on melanogenesis are beneficial for the treatment of hypopigmentation diseases. In the present study, mushroom tyrosinase activity assay was performed to screen tyrosinase activators from traditional Chinese herbs. Four components from Radix Polygoni multiflori were tested. The most active compound, 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (THSG), was found to be a significant tyrosinase activator. The maximal activation was 126% at a concentration of 75.0 microg/mL. The three anthraquinones slightly activated tyrosinase with effects in the range 7-31%. All the compounds were tested in B16 melanoma cells, the anthraquinones were found to inhibit cell proliferation at a concentration of 0.1-2.5 microg/mL, and THSG was found to be non-cytotoxic at a concentration of 0.1-12.5 microg/mL. THSG significantly increased the activity of murine tyrosinase and stimulated melanin biosynthesis in B16 melanoma cells. In conclusion, THSG is a potent tyrosinase activator and stimulator of melanogenesis with potential for the treatment of hypopigmentation disease.

Radix Polygoni multiflori is a herb used effectively to prevent graying and treat skin depigmentation diseases in traditional Chinese medicine but its active ingredients have not been discovered yet. In this investigation, we tested six compounds isolated from Radix Polygoni multiflori, to discover the active component on melanogenesis. Three experiments were performed in the present investigation: mushroom tyrosinase activity, melanin content B16 cell proliferation assay. Among all the six components tested, THSG showed the most potent effects on tyrosinase activation and melanogenesis; it was shown to be a potent tyrosinase activator and a melanogenesis stimulator in this study. On the other hand, we found that gallic acid significantly inhibited tyrosinase and, in addition, anthraquinones were cytotoxic to melanoma cells. They were both harmful to melanogenesis. Therefore, we propose that THSG acts as the active ingredient of Radix Polygoni multiflori on melanogenesis.

Danggui Sini decoction is a traditional Chinese medicine preparation commonly used in the treatment of blood stasis syndrome through a mechanism yet to be defined. Therefore, we have explored its mechanism of action by combining pharmacology and gut microbiota analysis. To this end, female Sprague-Dawley rats were divided into 5 groups, including the control group, the acute blood stasis group, the Danshen tablet-treated group, the low-dose Danggui Sini decoction group, and the high-dose Danggui Sini decoction group. Danggui Sini decoction led to a significant reduction in the changes in the whole blood viscosity and plasma viscosity of rats with acute blood stasis syndrome, improved the coagulation function and cardiopulmonary pathological injury, upregulated the plasma 6-keto prostaglandin F1α and endothelial nitric oxide synthase, and downregulated thromboxane B2 and endothelin-1. The high throughput 16S rRNA gene sequencing results showed that Danggui Sini decoction reduced the number of pathogenic proteobacteria, significantly reduced erysipelas and suzericella, and increased the beneficial bacteria Roche, effectively improving the status of intestinal flora disorder in acute blood stasis rats. The Spearman correlation analyses showed that there was a close correlation between intestinal flora distribution and changes in blood stasis-related biochemical indices. In addition, network pharmacological analysis showed that the epidermal growth factor receptor, tumor protein p53, signal transducer and activator of transcription 3, vascular endothelial growth factor A, and hypoxia-inducible factor 1-alpha were the core targets of Danggui Sini decoction in alleviation of blood stasis. Further genetic ontological and pathway enrichment analyses suggested that the therapeutic effect of Danggui Sini decoction on blood stasis involved the lipid and atherosclerosis pathways, advanced glycation end-product-receptor for advanced glycation end-product signaling pathways in diabetic complications, fluid shear stress and atherosclerosis pathways, and hypoxia-inducible factors, 1-alpha signaling pathway, phosphatidylinositol 3-kinase- protein kinase B signaling, and other pathways. These results are helpful in understanding the mechanism by which Danggui Sini decoction improves blood stasis and provide a reference for further research.