Résumé
BACKGROUND: In our preliminary study, we screened for their potential to inhibit 5α-reductase, and Melandrium firmum (MF) extract showed the most potent activity as confirmed by high-performance liquid chromatography (HPLC). OBJECTIVE: This study aimed to investigate the effects of MF extract on 5α-reductase activity and its mechanisms of action in the prevention or treatment of androgenetic alopecia. METHODS: HPLC was used to measure 5α-reductase activity. The hair growth-promoting effect of MF extract in the shaved dorsal skin of C57BL/6J mice was studied for 30 days. Hair follicles were examined by histological examination. Protein and mRNA levels of growth factors involved in hair growth were determined by western blotting, and reverse transcription-polymerase chain reaction (RT-PCR) and qPCR, respectively. Cell proliferation was measured by (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. RESULTS: MF extract at 0.5 mg/ml showed 43.5% inhibition of 5α-reductase. MF extract promoted hair growth by inducing anagen phase reflected by skin color, hair density, and the number and size of hair follicles. It not only reduces the expression of transforming growth factor-beta 1 (TGF-β1) and Dickkopf-1 (DKK-1), but also markedly upregulated insulin-like growth factor 1 and keratinocyte growth factor in the dorsal dermal tissue. Ursolic acid, ecdcysteron, and ergosterol peroxide were identified as active constituents by activity-guided fractionation to inhibit 5α-reductase. They decreased the gene expression of TGF-β1 and DKK-1 in human hair dermal papilla cells. CONCLUSION: In summary, these finding indicate that MF extract might be a good drug candidate for hair growth promotion.