Piceid (5,4'-dihydroxystilbene-3-O-β-D-glucopyranoside) is one of the stilbenes found in Polygonum cuspidatum. Previous studies have shown that this compound has little effect on tyrosinase inhibition when compared with other stilbenes in a cell-free tyrosinase assay. Furthermore, its role for melanogenesis in melanocytes is relatively unknown. In melanocytes, piceid inhibits tyrosinase activity and melanin production in a concentration-dependent manner. To explore the action of piceid on melanogenesis, we studied its effect on several key cellular enzymes and a transcriptional factor known to be involved in melanogenesis, including: tyrosinase, tyrosinase-related protein 1, tyrosinase-related protein 2, and microphthalmia-associated transcription factor. Interestingly, the effects of piceid on hypopigmentation and inhibition of tyrosinase activity were better than those of arbutin, which is well known to inhibit melanin formation in melanocytes. In addition, piceid suppressed the mRNA and protein expression of the aforementioned enzymes and transcriptional factor in a concentration-dependent manner. In this regards, our results showed that piceid represents a safe and new candidate for a skin-lightening agent.

Houttuynia cordata (HC) is a traditional oriental herbal medicinal plant widely used as a component of complex prescriptions in Asia for alopecia treatment. The effect of HC on hair growth and its underlying mechanism, however, have not been demonstrated or clarified. In this study, we investigated the hair growth promoting effect of HC in cultured human dermal papilla cells (hDPCs). HC extract was found to stimulate the proliferation of hDPCs and this stimulation might be in part a consequence of activated cellular energy metabolism, because treatment of HC extract increased the generation of nicotinamide adenine dinucleotide (NADH) and ATP through increasing the mitochondrial membrane potential (ΔΨ). In the context of cell cycle, HC extract increased the expression of CDK4 and decreased the expression of CCNA2 and CCNB1, implying that HC extract might induce G1 phase progression of DPCs which resulted in enhanced proliferation. HC extract increased the expression of Bcl2 essential for maintaining hair follicle anagen stage and cell survival. On the contrary, the expression of p16 and p21 was down-regulated by HC extract. In addition, HC extract enhanced the secretion of platelet-derived growth factor (PDGF)-aa and vascular endothelial growth factor (VEGF) and induced phosphorylation of extracellular signal-regulated kinase (ERK) and AKT. Furthermore, HC extract prolonged anagen stage in organ cultured human hair follicles. Our data strongly suggest that HC extract could support hair growth by stimulating proliferation of DPCs and elongating anagen stage, resulted from enhanced cellular energy metabolism and modulation of gene expression related to cell cycle, apoptosis, and growth factors.

Background: Dermal papilla cells (DPCs) play a key role in hair growth among the various cell types in hair follicles. Especially, DPCs determine the fate of hair follicle such as anagen to telogen transition and play a pivotal role in androgenic alopecia (AGA). This study was performed to elucidate the hair growth promoting effects of Polygonum multiflorum extract (PM extract) in cultured human DPCs and its underlying mechanisms. Methods:The effects of PM extract on cultured DPCs were investigated. Cell viability and mitochondrial activity were measured by CCK-8 and JC-1 analysis, respectively. Western blotting, dot blotting, ELISA analysis, immunocytochemistry and real-time PCR analysis were also performed to elucidate the changes in protein and mRNA levels induced by PM extract. 3D cultured DPC spheroids were constructed for mimicking the in vivo DPs. The hair growth stimulatory effect of PM extract was evaluated using human hair follicle organ culture model. Results: PM extract increased the viability and mitochondrial activity in cultured human DPCs in a dose dependent manner. The expression of Bcl2, an anti-apoptotic protein expressed dominantly in anagen was significantly increased and that of BAD, a pro-apoptotic protein expressed in early catagen was decreased by PM extract in cultured DPCs and/or 3D DPC spheroid culture. PM extract also decreased the expression of catagen inducing protein, Dkk-1. Growth factors including IGFBP2, PDGF and VEGF were increased by PM extract, revealed by dot blot protein analysis. We also have found that PM extract could reverse the androgenic effects of dihydrotestosterone (DHT), the most potent androgen. Finally, PM extract prolonged the anagen of human hair follicles by inhibiting catagen entry in human hair follicle organ culture model. Conclusion:Our data strongly suggest that PM extract could promote hair growth by elongating the anagen and/ or delaying the catagen induction of hair follicles through activation of DPCs.

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Background:Fibroblasts produce many components of the extracellular matrix (ECM) and so they contribute to the maintenance of connective tissue integrity. Objective: The aim of this study is to evaluate the effect of velvet antler extract (VAE) on the ECM production of dermal fibroblasts cultured in vitro. Methods: Primary cultured human dermal fibroblasts were treated with VAE, and then the ECM production was determined by RT-PCR, ELISA and Western blot analysis. Furthermore, the change of gene expression according to VAE treatment was evaluated by cDNA microarray. Results: VAE accelerated the growth of fibroblasts in a dose-dependent manner. VAE increased the production of several ECM components, including type 1 collagen, fibronectin and elastin. In line with these results, the phosphorylations of p42/44 ERK and p38 mitogen-activated protein kinase were markedly increased by VAE, suggesting that the enhancement of ECM production may be linked to the activation of intracellular signaling cascades. VAE also significantly increased cell migration on an in vitro scratch wound test. In cDNA microarray, many genes related with connective tissue integrity were identified to be up-regulated by VAE. Conclusion: These results suggest that VAE has a potential to stimulate ECM production, and VAE may be applicable for maintaining the skin's texture.