Sirisopa Patcharawan, Leepasert Theerachart, Karpkird Thitinun, Nararak Jirod, Thanispong Kanutcharee, Ahebwa Alex, Chareonviriyaphap Theeraphap
Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand.
Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
Insects. 2024 Sep 18;15(9):712. doi: 10.3390/insects15090712.
Infectious diseases that cause illness and/or death in humans can be contracted from mosquito bites. A viable and alternate method of personal protection that can lower the danger of human exposure to mosquito-borne diseases is the use of plant-based repellents. Using a high-throughput screening system, the current work examined the toxicity, contact irritancy, and spatial repellency of crude extract and its fractions against , , and . Five fractions (i.e., F1, F2, F3, F4, and F5) were separated from the crude extract by column and thin layer chromatography and analyzed using high-performance liquid chromatography and mass spectrometry. The major active compounds identified from F3 and F5 were 4-deoxy-11,12-didehydroandrographolide and andrographolide. Three concentrations (1.0, 2.5, and 5.0%) for each of the crude extracts and the five fractions were individually impregnated on nylon netting strips and evaluated against the three mosquito species. Results showed that the highest contact irritancy was elicited by the crude extract at 5% concentration against (43.70% escaped). Results of the spatial activity index (SAI) showed that fractions F3 and F5 at 2.5% demonstrated the strongest repellency against (SAI = 0.84) and (SAI = 0.83), respectively. Both the crude extract and its components did not cause any knockdown or mortality. These findings suggest that fractionation of extracts is valuable in assessing their spatial repellent efficacy against mosquitoes. Fractions F3 and F5 hold promise as natural mosquito repellents and could contribute to developing effective mosquito control strategies.
可通过蚊虫叮咬感染导致人类患病和/或死亡的传染病。使用植物性驱避剂是一种可行的个人防护替代方法，可降低人类接触蚊媒疾病的风险。本研究利用高通量筛选系统，检测了粗提物及其馏分对[蚊虫种类1]、[蚊虫种类2]和[蚊虫种类3]的毒性、接触刺激性和空间驱避性。通过柱色谱和薄层色谱从粗提物中分离出五个馏分（即F1、F2、F3、F4和F5），并使用高效液相色谱和质谱进行分析。从F3和F5中鉴定出的主要活性化合物为4-脱氧-11,12-二脱氢穿心莲内酯和穿心莲内酯。将粗提物和五个馏分各自的三种浓度（1.0%、2.5%和5.0%）分别浸渍在尼龙网带上，并针对三种蚊虫进行评估。结果表明，5%浓度的粗提物对[蚊虫种类1]引起的接触刺激性最高（43.70%逃脱）。空间活性指数（SAI）结果表明，2.5%的F3和F5馏分分别对[蚊虫种类2]（SAI = 0.84）和[蚊虫种类3]（SAI = 0.83）表现出最强的驱避性。粗提物及其成分均未引起任何击倒或死亡。这些发现表明，[植物名称]提取物的分馏对于评估其对蚊虫的空间驱避效果具有重要价值。F3和F5馏分有望成为天然蚊虫驱避剂，并有助于制定有效的蚊虫控制策略。
