Yang Young-Cheol, Lee Hoi-Seon, Lee Si Hyeock, Clark J Marshall, Ahn Young-Joon
Research Institute, Naturobiotech Co., Ltd., Suwon 441-744, South Korea.
Int J Parasitol. 2005 Dec;35(14):1595-600. doi: 10.1016/j.ijpara.2005.08.005. Epub 2005 Sep 15.
The toxicity of cinnamon, Cinnamomum zeylanicum, bark essential oil compounds against eggs and adult females of human head louse, Pediculus humanus capitis, was examined using direct contact and vapour phase toxicity bioassays and compared with the lethal activity of their related compounds, benzyl alcohol, cinnamic acid, cinnamyl acetate, 4-hydroxybenzaldehyde and salicylaldehyde, as well as two widely used pediculicides, d-phenothrin and pyrethrum. In a filter-paper contact toxicity bioassay with female lice at 0.25 mg/cm(2), benzaldehyde was 29- and 27-fold more toxic than pyrethrum and d-phenothrin, respectively, as judged by median lethal time (LT(50)) values. Salicylaldehyde was nine and eight times more active than pyrethrum and d-phenothrin, respectively. Pediculicidal activity of linalool was comparable with that of d-phenothrin and pyrethrum. Cinnamomum bark essential oil was slightly less effective than either d-phenothrin or pyrethrum. Benzyl alcohol and (E)-cinnamaldehyde exhibited moderate pediculicidal activity. After 24h of exposure, no hatching was observed with 0.063 mg/cm(2) salicylaldehyde, 0.125 mg/cm(2) benzaldehyde, 0.5mg/cm(2)Cinnamomum bark essential oil, 1.0 mg/cm(2) (E)-cinnamaldehyde, and 1.0 mg/cm(2) benzyl cinnamate. Little or no ovicidal activity was observed with d-phenothrin or pyrethrum. In vapour phase toxicity tests with female lice, benzaldehyde and salicylaldehyde were much more effective in closed containers than in open ones, indicating that the mode of delivery of these compounds was largely due to action in the vapour phase. Neither d-phenothrin nor pyrethrum exhibited fumigant toxicity. Cinnamomum bark essential oil and test compounds described merit further study as potential pediculicides or ovicides for the control of P. h. capitis.
采用直接接触和气相毒性生物测定法，检测了锡兰肉桂（Cinnamomum zeylanicum）树皮精油化合物对人头虱（Pediculus humanus capitis）卵和成年雌虱的毒性，并将其与相关化合物苯甲醇、肉桂酸、肉桂酸乙酯、4-羟基苯甲醛和水杨醛以及两种广泛使用的杀虱剂右旋苯醚菊酯和除虫菊的致死活性进行了比较。在滤纸接触毒性生物测定中，以0.25mg/cm²的剂量处理雌虱，通过半数致死时间（LT₅₀）值判断，苯甲醛的毒性分别比除虫菊和右旋苯醚菊酯高29倍和27倍。水杨醛的活性分别比除虫菊和右旋苯醚菊酯高9倍和8倍。芳樟醇的杀虱活性与右旋苯醚菊酯和除虫菊相当。肉桂树皮精油的效果略低于右旋苯醚菊酯或除虫菊。苯甲醇和（E）-肉桂醛表现出中等的杀虱活性。暴露24小时后，0.063mg/cm²的水杨醛、0.125mg/cm²的苯甲醛、0.5mg/cm²的肉桂树皮精油、1.0mg/cm²的（E）-肉桂醛和1.0mg/cm²的肉桂酸苄酯均未观察到孵化现象。右旋苯醚菊酯或除虫菊几乎没有杀卵活性。在对雌虱的气相毒性试验中，苯甲醛和水杨醛在密闭容器中比在开放容器中更有效，这表明这些化合物的作用方式主要是气相作用。右旋苯醚菊酯和除虫菊均未表现出熏蒸毒性。肉桂树皮精油和所描述的测试化合物作为控制人头虱的潜在杀虱剂或杀卵剂值得进一步研究。
