Department of Environmental Health, High Institute of Public Health, Alexandria University, 165 El-Horreya Ave., 21561-El-Hadara, Alexandria, Egypt.
Department of Pesticide Chemistry and Technology, Faculty of Agriculture, 21545-El-Shatby, Alexandria University, Alexandria, Egypt.
Pestic Biochem Physiol. 2022 Jul;185:105151. doi: 10.1016/j.pestbp.2022.105151. Epub 2022 Jun 20.
The chemical composition of cypress, lavender, lemon eucalyptus, and tea tree oils has been investigated using gas chromatography/mass spectrometry (GC/MS). These oils were tested for larvicidal activity against Culex pipiens alongside their nanoemulsions (NEs) and conventional emulsifiable concentrates (ECs). Oil-in-water (O/W) NEs preparation was based on a high-energy ultra-sonication technique. The effect of independent variables of preparation on the different outputs was studied using the response surface method to obtain the optimum preparation technique. The droplet sizes of prepared NEs were significantly different (71.67, 104.55, 211.07, and 70.67 for cypress, lavender, lemon eucalyptus, and Tea tree NEs, respectively). The zeta potentials of NEs were recorded to have a high negatively charge (-28.4, -22.2, -23.6, and - 22.3 mV for cypress, lavender, lemon eucalyptus, and tea tree NEs, respectively). The results showed that the tea tree oil has the most significant effect with LC = 60.02 and 57.10 mg/L after 24 and 48 h of exposure, respectively. In comparison, cypress oil proved the lowest toxicity with LC values of 202.24 and 180.70 mg/L after 24 and 48 h, respectively. However, lavender oil does not show any effect against larvae at tested concentrations. In addition, pure oil exhibited the lowest larvicidal activity. However, the EC of all tested insecticides slightly improved the toxic action against the larvae. While the NEs showed significantly high toxicity compared to the EO and EC. An in vivo assessment of acetylcholine esterase (AChE), adenosine triphosphatase (ATPase), and gamma-aminobutyric acid transaminase (GABA-T) revealed that the NEs exhibited higher activity than the pure oils and ECs. This work describes these oils with potential use against C. pipiens larvae as eco-friendly products.
采用气相色谱/质谱联用（GC/MS）法研究了柏木、薰衣草、柠檬桉和茶树油的化学成分。测试了这些油对库蚊幼虫的杀幼虫活性，以及它们的纳米乳液（NE）和常规可乳化浓缩物（EC）。油包水（O/W）NE 的制备基于高能超声技术。使用响应面法研究了制备过程中独立变量对不同产物的影响，以获得最佳的制备技术。所制备的 NE 的液滴尺寸有显著差异（柏木、薰衣草、柠檬桉和茶树油的 NE 分别为 71.67、104.55、211.07 和 70.67nm）。记录 NE 的 Zeta 电位以具有高负电荷（柏木、薰衣草、柠檬桉和茶树油的 NE 分别为-28.4、-22.2、-23.6 和-22.3mV）。结果表明，茶树油在暴露 24 和 48 小时后的 LC50 值分别为 60.02 和 57.10mg/L，效果最为显著。相比之下，柏木油在 24 和 48 小时后的 LC50 值分别为 202.24 和 180.70mg/L，毒性最低。然而，薰衣草油在测试浓度下对幼虫没有任何作用。此外，纯油表现出最低的杀幼虫活性。然而，所有测试杀虫剂的 EC 略微提高了对幼虫的毒性作用。而 NE 与 EO 和 EC 相比，显示出显著的高毒性。体内评估乙酰胆碱酯酶（AChE）、三磷酸腺苷酶（ATPase）和γ-氨基丁酸转氨酶（GABA-T）表明，NE 比纯油和 EC 具有更高的活性。这项工作描述了这些具有潜在用途的油类，可以作为防治库蚊幼虫的环保产品。
