The first in vitro evaluation of acaricide paeonol against human Demodex (Acari: Demodicidae)

Abstract Background Human Demodex (classified into Demodex folliculorum and Demodex brevis) causes multiple skin disorders, including pityriasis folliculorum, folliculitis, rosacea, blepharitis, seborrheic dermatitis, and perioral dermatosis. Paeonol, with prolonged history of use in modern China, exhibits several beneficial effects such as anti-insect, anti-inflammatory, neuroprotective, antitumor, and anti-cardiovascular diseases. Purpose To evaluate the in vitro effectiveness of paeonol, the main component isolated from the root bark of Paeonia suffruticosa, against human Demodex. Methods A paeonol solution was prepared using paraffin oil, and human Demodex mites were obtained using the cellophane tape method. The drug solution was directly used to contact and kill both Demodex species in vitro. Results The experiment showed that 40 mg/mL was the minimum effective concentration of paeonol for killing the two mite species; paeonol exhibited more remarkable killing effect on D. brevis than on D. folliculorum. Conclusions This result suggests that paeonol has good in vitro acaricidal activity against human Demodex mite. Moreover, it is more effective against D. brevis than against D. folliculorum.