<i>Angelica sinensis</i> and <i>Ligusticum sinense ‘Chuanxiong’</i> Leaf Essential Oils Promote Hair Growth without Acute Toxicity

Background Rhizome Angelica sinensis and Ligusticum sinense ‘chuanxiong’ are the main medicinal herbs used in traditional Chinese or Asian medicine to treat alopecia likely associated with their expertise in invigorating blood circulation. However, the effects of the volatile essential oils present in their aboveground parts are unclear. Objective To evaluate the general safety of essential oils from A. sinensis and L. sinense ‘chuanxiong’ leaves and evaluate their hair grow promoting effect on model mice and cells of dehydrotestosterone-induced androgenetic alopecia. Methods Essential oil safety was evaluated based on acute oral/dermal/eye irritation toxicity tests on laboratory animals. Essential oils (5%, 3% and 1%) were topically applied to model mice with dehydrotestosterone-induced androgenetic alopecia for 28 days. They (50-200 mg/L) were appended to the monoculture of model cells of dehydrotestosterone-induced androgenetic alopecia for 48 h. Results Both essential oils showed no acute toxicity. Mice dorsal skin indicated faster hair regrowth initiated by essential oils than by 3% minoxidil. Histological analysis shows that both essential oils increased the follicle number and dermal thickness in mice treated with dehydrotestosterone, with 1% A. sinensis and 3% L. sinense ‘chuanxiong’ essential oils performing the best. The 1% A. sinensis and 3% L. sinense ‘chuanxiong’ essential oils exhibited an average number of hair follicles (pcs/field of view) of 69.73 and 70.13, respectively, which were significantly larger than that of the model (14.80) and minoxidil (36.53) treated mice. Both essential oils significantly reversed the dehydrotestosterone-induced inhibition of secretion of hair growth promotors, the vascular endothelial growth factor and keratinocyte growth factor, in cultured cells. Conclusion A. sinensis and L. sinense ‘chuanxiong’ essential oils may act as safe and effective adjuvant agents in aromatherapy and cosmetics to treat human hair loss.