Polygonum multiflorum root extract as a potential candidate for treatment of early graying hair

Abstract

Despite Polygonum multiflorum (PM) has been experiencely used as a drug to treat early graying hair phenomenon in Asian countries for a long time, there is limited study examined the real biological effects of PM on hair graying in vitro and in vivo. In this study, we investigated the effects of PM root extract (PM-RE) on melanin synthesis in human melanoma SKMEL-28 cells and embryos/larvae of wild-type strain AB zebrafish. We also preliminary revealed the molecular mechanism of early hair graying phenomenon in both in vitro and in vivo models. Our results showed that PM-RE significantly induced melanin synthesis in melanin-producing SKMEL-28 melanoma cells and also in zebrafish embryos/larvae at 4-day postfertilization through activation of MC1R/MITF/tyrosinase-signaling pathway. We also investigated the differences in genotype between graying hair follicle and black hair follicle of young peoples and found that early hair graying phenomenon may be related to downregulation of MC1R/MITF/tyrosinase pathway. Taken together, we suggested that PM-RE at safe doses could be used as a potential agent for the treatment of early hair graying and other loss pigmentation-related diseases.

Keywords: Graying hair; MC1R/MITF/tyrosinase signaling; Polygonum multiflorum; melanin synthesis; zebrafish.

Figure 1

Transcript expression levels of MC1R, MITF, and tyrosinase in black (b) and graying (g) hair follicles are presented in a picture (a) and a graph (b). Expression levels of glyceraldehyde-3-phosphate dehydrogenase are presented as an internal control

Figure 2

Toxicological effect of Polygonum multiflorum extract on SMEL-28 cells is presented in a picture (a) and a graph (b). Tested concentrations of Polygonum multiflorum extract were 0 (negative control), 312 (C1), 625 (C2), 1250 (C3), 2500 (C4), and 5000 (C5) μg/ml

Figure 3

Melanins formed by SMEL-28 cells are presented in pictures (a and b). Total melanin synthesis by SKMEL-28 cells is presented in a graph (c). Tested concentrations of Polygonum multiflorum extract were 0 (negative control), 312, 625, and 2500 μg/ml

Figure 4

Transcript expression levels of MC1R/MITF/tyrosinase in SKMEL-28 cells are presented in a picture (a) and a graph (b). Glyceraldehyde-3-phosphate dehydrogenase is used as an internal control

Figure 5

Toxicity of Polygonum multiflorum root extract on zebrafish embryos/larvae. (a) Zebrafish embryos at 4-day postfertilization without any treatment used as negative control; zebrafish embryos treated with Polygonum multiflorum root extract at 175 mg/L at 3-day postfertilization (b); 295 mg/L at 3-day postfertilization (c); 295 mg/L at 4-day postfertilization (d); 385 mg/L at 3-day postfertilization (e); 385 mg/L at 4-day postfertilization (f); 500 mg/L at 3-day postfertilization (g), and 500 mg/L at 4-day postfertilization (h). (i) Graph indicates the EC50 and LC50 of zebrafish embryos exposed to Polygonum multiflorum root extract

Figure 6

Effect of Polygonum multiflorum root extract on melanin formation in zebrafish embryos/larvae. Morphology of zebrafish embryos at 4-day postfertilization without (negative control) or with 225 mg/L (C2) Polygonum multiflorum root extract treatment (a). Total melanin formed in zebrafish embryos at 4-day postfertilization without (negative control) or with 135 mg/L (C1) and 225 mg/L (C2) Polygonum multiflorum root extract treatments (b). Transcript expression levels of MC1R, MITF, tyrosinase, and internal control Ef1α in zebrafish embryos exposed to Polygonum multiflorum root extract at 0 mg/L (negative control), 135 mg/L (C1), and 225 mg/L (C2), respectively, in a picture (c) and in graphs (d)