[Effects of five Chinese herbs on human demodicid mites in vitro]

To research the effects of five Chinese herbs of Artemisia argyi, Chimonanthus praecox, Agastache rugosa, pine needles and Osmamthus fragrans on human demodicid mites in vitro.

The human demodicid mites were acquired with the cellophane tape method. The ethanol heat reflux extractions were carried out on the 5 kinds of Chinese herbs to be studied and Stemona sessilifolia as the positive control, so as to get the herbal extracts. Next, the drug administration was carried out to the demodicid mites, and the inhibitory or killing effects of the 6 kinds of Chinese herbs above mentioned on the vermiform mites were observed under a microscope. It was considered to be dead when the bodies of the demodicid mites stopped moving. Besides, the duration from drug administration to death of the vermiform mites was recorded.

Artemisia argyi, Chimonanthus praecox and Agastache rugosa could effectively inhibit and kill human demodicid mites. The effect of Artemisia argyi and Agastache rugosa was similar to the effect of Stemona sessilifolia, and the effect of Chimonanthus praecox was weaker than Stemona sessilifolia's effect. Among them, Agastache rugosa took a relatively short time (4.60 min ± 1.66 min) min and Osmamthus fragrans took the longest time (114.65min ± 80.14min) to Demodex folliculorum; Whereas, Artemisia argyi took the shortest time (3.56min ± 1.92 min) min and Osmamthus fragrans took the longest time (194.24min ± 134.96 min) min to Demodex brevis.

The effects of Artemisia argyi and Agastache rugosa on human demodicid mites are similar to that of Stemona sessilifolia. The effects of Chimonanthus praecox and pine needles are weaker than that of Stemona sessilifolia. Osmamthus fragrans has no acaricidal effect.