A Natural Inhibitor, 1'S-1'-Acetoxychavicol Acetate, Against Testosterone-Induced Alopecia via NADPH Oxidase Regulation.

Androgenetic alopecia is associated with testosterone-mediated anagen-to-catagen transition and matrix keratinocyte apoptosis in hair follicle cells. Activation of Nox isozymes is involved in testosterone-mediated keratinocyte apoptosis, leading to androgenetic alopecia. This indicates that Nox isozymes can serve as therapeutic targets for androgenetic alopecia. The isolated compounds from natural products were screened to evaluate their ROS-inhibition efficacy and it was found that 1'S-1'-acetoxychavicol acetate (ACA, 26), a natural compound isolated from Alpinia galanga (L.) Willd. (Zingiberaceae), exhibits inhibitory activity on Nox isozymes. Nox inhibition by ACA suppressed testosterone-dependent H2O2 generation and cell death in keratinocytes. Incubation with ACA in human hair follicle organ culture mitigated testosterone-dependent suppression of hair growth. We validated that ACA regulates androgenetic alopecia in a mouse model. Local application of ACA on the dorsal skin in an androgenetic alopecia model of C57BL/6 mice significantly suppressed testosterone-induced hair loss in a dose-dependent manner. Moreover, hair follicle length in ACA-treated mice was enhanced compared to that in control mice. These findings provide a molecular mechanism in which ACA inhibits Nox activity in hair follicle cells, indicating its potential as an effective treatment of AGA.