Hair growth-promoting activity of components derived from sweet potato shochu

Sweet potato shochu oil is one of the by-products of sweet potato shochu production. We investigated the functionality and industrial use of shochu oil as a food-derived raw material. Because of the increased incidence of self-consciousness in people owing to thinning hair, in this study, we examined the hair growth-inducing effects of shochu oil. Minoxidil, the only topical medication approved for hair growth treatment in Japan, was used as a control for the evaluation of hair growth-promoting activity of shochu oil. Human follicle dermal papilla cells treated with shochu oil showed upregulated expression of vascular endothelial growth factor in a concentration-dependent manner, indicating that shochu oil induced the activation of the hair growth cycle. In vivo, epidermal treatment with shochu oil also promoted hair growth in C3H mice. More than 35 components were detected in shochu oil via gas chromatography–mass spectrometry. The main components, accounting for 98.5% of shochu oil, were as follows, in order of decreasing concentration: ethyl palmitate, ethyl linoleate, ethyl oleate, ethyl stearate, ethyl caprate, ethyl laurate, ethyl myristate, and ethyl α-linolenate. Among these, ethyl palmitate, ethyl linoleate, and ethyl α-linolenate promoted hair growth in C3H mice. These results indicate that shochu oil can be used as a hair restorer. To the best of our knowledge, this study is the first to demonstrate the hair growth-promoting activity of shochu oil.