Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80160, Thailand.
Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand.
J Med Entomol. 2022 Jan 12;59(1):291-300. doi: 10.1093/jme/tjab143.
Essential oil of Cananga odorata Hook. F. & Tomson is a source of insect repellent, but contact irritancy and noncontact repellency actions that stimulate insect's avoidance behavior (escape away from chemical source after direct physical contact or without making physical contact, respectively) have not been investigated. Therefore, an excito-repellency test chamber was used for measuring avoidance behavior of four insectary-reared mosquito species (Diptera: Culicidae) that escape from esposure to four concentrations (0.5, 1.0, 2.5, and 5.0% v/v) of C. odorata oil. The oil strongly repelled both Culex quinquefasciatus Say (85-97% escape) and Anopheles minimus Theobald (97-99%) at high concentrations (2.5-5.0%). For Anopheles dirus Peyton & Harrison and Aedes aegypti (L.), highest repellency (64 and 39% escape, respectively) was demonstrated at 2.5% concentration. For contact irritancy, the oil produced relatively high percent escape found in Cx. quinquefasciatus (90-100% escape) and An. minimus (83-100%). Whereas moderate contact irritancy was observed against An. dirus (40-50% escape) and Ae. aegypti (51-59%). The percent escape was then adjusted with repellency to estimate the effect of contact irritancy alone. We found that highest contact irritancy was presented at 0.5% concentration against An. minimus (67% escape). Knockdown and toxic actions were only found in Anopheles mosquitoes at 5.0% concentration. The results revealed that An. minimus and Cx. quinquefasciatus were more prone to be repelled by C. odorata oil. Detailed analysis of oil identified primary compounds as methyl benzoate (14.6%), α-gurjunene (12.8%), p-methyl-anisole (11.3%), and benzyl acetate (9.9%). Further investigations are needed to assess excito-repellency actions of these compounds alone or in combination.
依兰香精油是一种驱虫剂，但接触性刺激和非接触性驱避作用（分别是在直接物理接触后或不进行物理接触的情况下刺激昆虫回避行为）尚未被研究。因此，使用激扰驱避测试室来测量四种饲养蚊虫（双翅目：蚊科）对四种浓度（0.5、1.0、2.5 和 5.0%v/v）依兰香精油的回避行为。该精油在高浓度（2.5-5.0%）下对库蚊（85-97%回避）和微小按蚊（97-99%回避）有强烈的驱避作用。对于致倦库蚊和埃及伊蚊，在 2.5%浓度下表现出最高的驱避率（分别为 64%和 39%回避）。对于接触性刺激，库蚊（90-100%回避）和微小按蚊（83-100%回避）中发现的精油产生了相对较高的回避率。而对致倦库蚊（40-50%回避）和埃及伊蚊（51-59%回避）则观察到中度接触性刺激。然后，用驱避率来调整回避率，以估计接触性刺激的单独作用。我们发现，在 0.5%浓度下，依兰香精油对微小按蚊的接触性刺激最大（67%回避）。击倒和毒性作用仅在 5.0%浓度下的按蚊中发现。结果表明，微小按蚊和库蚊更容易被依兰香精油驱避。对精油的详细分析确定了主要化合物为苯甲酸甲酯（14.6%）、α-古巴烯（12.8%）、对甲氧基苯甲醚（11.3%）和乙酸苄酯（9.9%）。需要进一步研究这些化合物单独或组合的激扰驱避作用。
