Repellent activity of catmint, Nepeta cataria, and iridoid nepetalactone isomers against Afro-tropical mosquitoes, ixodid ticks and red poultry mites
Repellent activity of catmint, Nepeta cataria, and iridoid nepetalactone isomers against Afro-tropical mosquitoes, ixodid ticks and red poultry mites
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DOI：
10.1016/j.phytochem.2010.09.016
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发表时间：
2011-01-01
期刊：
影响因子：
3.8
通讯作者：
Pickett, John A.
中科院分区：
文献类型：
--
作者：
Birkett, Michael A.;Hassanali, Ahmed;Pickett, John A.
评价猫薄荷植物荆芥（唇形科）的精油和主要的环烯醚萜化合物（4aS，7S，7aR）和（4aS，7S，7aS）-荆芥内酯对（i）主要的非洲热带病原体媒介蚊子，即疟疾蚊子，冈比亚按蚊s.s.和南方家蚊，致倦库蚊，使用世界卫生组织（WHO）批准的局部应用生物测定法，（ii）棕耳蜱，扇头蜱，使用攀援驱避性测定法，和（iii）红色家禽螨，鸡皮刺螨，使用现场诱捕实验。采用气相色谱（GC）和气相色谱-质谱（GC-MS）联用技术对两种N.在驱避性测定中使用的cataria化学型（A和B）显示，（4aS，7S，7aR）和（4aS，7S，7aS）-荆芥内酯以不同比例存在，其中一种油（来自化学型A）由（4aS，75，7aR）异构体（91.95%，通过GC），和其它油（来自化学型B）含有两种（4a 5，7S，7aR）和（4aS，75，7a 5）异构体，分别为16.98%和69.83%（通过GC）。倍半萜烯烃（E）-（1 R，9 S）-香紫苏烯被鉴定为油中唯一的其它主要组分（通过GC分别为8.05%和13.19%）。使用局部应用生物测定，油对An表现出高驱避活性（化学型A RD（50）= 0.081 mg cm（-2）和化学型B RD（50）= 0.091 mg cm（-2））。冈比亚可比的合成驱蚊剂避蚊胺（RD（50）= 0.12毫克厘米（-2）），而Cx。化学型A和化学型B的驱避活性分别为0.34 mg cm（-2）和0.074 mg cm（-2）。针对An的进一步排斥性测试。与化学型A和B油相比，使用纯化的（4a.S.7.5，7aR）和（4aS，7S，7aS）-荆芥内酯异构体的冈比亚油显示出总体较低的驱避活性。在一定比例范围内，但全部以相同的总剂量（0.1 mg）测试（4aS，7S，7aR）和（4a 5，7S，7aS）异构体的二元混合物，不仅揭示了两者之间的协同效应，而且还揭示了令人惊讶的比例依赖性效应，对于纯异构体和等同或接近等同的混合物具有较低的活性，但对于非等同比例具有较高的活性。此外，当以相当于0.1和0.01 mg化学型B油的两个剂量测试时，（4aS，7S，7aR）和（4aS，7S，7aS）异构体的二元混合物（其比例相当于化学型B油中发现的比例）比油本身更不驱避。包括在化学型B油中发现的水平的（E）-（1 R，9 S）-卡环烯的三组分共混物具有与化学型B油相同的活性。在蜱爬驱避试验中，使用R.对于apapturatus，所述油显示出与其它驱避精油的数据相当的高驱避活性（化学型A RD（50）= 0.005 mg和化学型B RD（50）= 0.0012 mg）。在田间诱捕试验中，D. gallinae，添加化学型A和B油，以及两者的组合。gallinae，均显著降低了D.捕鸡器总之，这些数据表明，尽管荆芥内酯异构体具有用于保护人类和牲畜免受主要病原体载体侵害的潜力，但其是完整的，即未分级的。荆芥属由于存在荆芥内酯异构体和其它组分如（E）-（1 R，9 S）-香芹烯，油提供潜在的更大保护。(C)2010爱思唯尔有限公司版权所有。
The repellent activity of the essential oil of the catmint plant, Nepeta cataria (Lamiaceae), and the main iridoid compounds (4aS,7S,7aR) and (4aS,75,7aS)-nepetalactone, was assessed against (i) major Afro-tropical pathogen vector mosquitoes, i.e. the malaria mosquito, Anopheles gambiae s.s. and the Southern house mosquito, Culex quinquefasciatus, using a World Health Organisation (WHO)-approved topical application bioassay (ii) the brown ear tick, Rhipicephalus appendiculatus, using a climbing repellency assay, and (iii) the red poultry mite, Dermanyssus gallinae, using field trapping experiments. Gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS) analysis of two N. cataria chemotypes (A and B) used in the repellency assays showed that (4aS,7S,7aR) and (4aS,7S,7aS)-nepetalactone were present in different proportions, with one of the oils (from chemotype A) being dominated by the (4aS,75,7aR) isomer (91.95% by GC), and the other oil (from chemotype B) containing the two (4a5,7S,7aR) and (4aS,75,7a5) isomers in 16.98% and 69.83% (by GC), respectively. The sesquiterpene hydrocarbon (E)-(1R,9S)-caryophyllene was identified as the only other major component in the oils (8.05% and 13.19% by GC, respectively). Using the topical application bioassay, the oils showed high repellent activity (chemotype A RD(50) = 0.081 mg cm(-2) and chemotype B RD(50) = 0.091 mg cm(-2)) for An. gambiae comparable with the synthetic repellent DEET (RD(50) = 0.12 mg cm(-2)), whilst for Cx. quinquefasciatus, lower repellent activity was recorded (chemotype A RD(50) = 0.34 mg cm(-2) and chemotype B RD(50) = 0.074 mg cm(-2)). Further repellency testing against An. gambiae using the purified (4a.S.7.5,7aR) and (4aS,7S,7aS)-nepetalactone isomers revealed overall lower repellent activity, compared to the chemotype A and B oils. Testing of binary mixtures of the (4aS,7S,7aR) and (4a5,75,7aS) isomers across a range of ratios, but all at the same overall dose (0.1 mg), revealed not only a synergistic effect between the two, but also a surprising ratio-dependent effect, with lower activity for the pure isomers and equivalent or near-equivalent mixtures, but higher activity for non-equivalent ratios. Furthermore, a binary mixture of (4aS,7S,7aR) and (4aS,75,7aS) isomers, in a ratio equivalent to that found in chemotype B oil, was less repellent than the oil itself, when tested at two doses equivalent to 0.1 and 0.01 mg chemotype B oil. The three-component blend including (E)-(1R,9S)-caryophyllene at the level found in chemotype B oil had the same activity as chemotype B oil. In a tick climbing repellency assay using R. appendiculatus, the oils showed high repellent activity comparable with data for other repellent essential oils (chemotype A RD(50) = 0.005 mg and chemotype B RD(50) = 0.0012 mg). In field trapping assays with D. gallinae, addition of the chemotype A and B oils, and a combination of the two, to traps pre-conditioned with D. gallinae, all resulted in a significant reduction of D. gallinae trap capture. In summary, these data suggest that although the nepetalactone isomers have the potential to be used in human and livestock protection against major pathogen vectors, intact, i.e. unfractionated. Nepeta spp. oils offer potentially greater protection, due to the presence of both nepetalactone isomers and other components such as (E)-(1R,9S)-caryophyllene. (C) 2010 Elsevier Ltd. All rights reserved.