Effectiveness of essential oils of medicinal plants at reducing the amounts of allergen produced by the European house dust mite, <i>Dermatophagoides pteronyssinus</i> (Trouessart)

Abstract

Essential oils obtained from three medicinal plant species, namely, cinnamon (Cinnamomum bejolghota [Buch.-Ham.]Sweet), citronella grass (Cymbopogon nardus Rendle), and clove (Syzygium aromaticum [L.] Merr.& L. M. Perry), were sprayed on allergenic materials (house dust plus spent mite medium produced by the European house dust mite, Dermatophagoides pteronyssinus [Trouessart]) to evaluate the effects of the oils on allergen levels.A 1% solution of each essential oil in 95% ethanol was sprayed on the allergenic materials (which contained about 50 µg of allergen per gram of material), and 95% ethanol, water, and untreated allergenic materials were used as controls.The sprayed materials were allowed to stand for 48 h, and then allergen levels were analyzed by means of an enzyme-linked immunosorbent assay method.The results showed that the essential oil from C. bejolghota reduced the amount of allergen＞99.4%,and the essential oils from C. nardus and S. aromaticum reduced the amounts by 77.1% and 74.0%, respectively.In contrast, the 95% ethanol control reduced the amount of allergen by only 9.8%.