Effects of eucalyptus extract on hair propertiesand their molecular mechanisms.
Hiroyuki Taguchi, Sachie Ueda, Chie Ogawa, Hiroshi Yoshida, Shigeru Moriwaki, Takashi Kitahara, Biological Science Laboratories, KAO Corporation, 2606 Akabane Ichikai Haga Tochigi 321-3497, Japan.
Characterization and modification of physicochemical properties of hair are essential to develop cosmetic products and advance the biological and cosmetic hair sciences. We previously demonstrated that a long-term topical application of Eucalyptus extract on human scalp has improved physical factors, which determine the appearance, elasticity, luster, bounce and manageability of hair. However, the mechanism of action remained unclear. In this study, the molecular mechanisms underlying these effects of Eucalyptus extract were examined in vivo and in vitro. Ten healthy volunteers participated in the 3-week study. The half of the scalp was treated with a lotion contains 3% Eucalyptus extract and the other half was treated with a placebo lotion contains all of the test lotion except Eucalyptus extract. Anagen hairs were plucked from both test-sites of the scalp before and after the 3-week treatment. The transcriptional profiles of the hair root cells were compared using DNA microarray hybridization and quantitative RT-PCR. The effect of Eucalyptus extract was also examined in human cultured keratinocytes and dermal papilla cells to find putative genes responsible for improving hair properties. In hair root cells treated with Eucalyptus extract, genes related to the structural constituent, such as filaggrin, S100A8, desmoplakin and epiplakin1 were down-regulated, whereas VEGF and KRTAP4-12 genes were up-regulated. In the human cultured keratinocytes, it was confirmed that Eucalyptus extract up-regulated VEGF gene expression and induced VEGF protein secretion. Furthermore, VEGF was found to have a role to decrease desmoplakin gene expression in the human cultured keratinocytes. These results lead us to predict the involvement of VEGF and desmoplakin in the effect of Eucalyptus extract on hair properties.
