Dinesh Diwakar Singh, Kumari Seema, Pandit Vibhishan, Kumar Jainendra, Kumari Nisha, Kumar Prahlad, Hassan Faizan, Kumar Vijay, Das Pradeep
Division of Vector Biology & Control, Rajendra Memorial Research Institute of Medical Sciences (ICMR), Patna, India.
Indian J Med Res. 2015 Dec;142 Suppl(Suppl 1):S95-S100. doi: 10.4103/0971-5916.176633.
BACKGROUND & OBJECTIVES: Phlebotomus argentipes (Diptera: Psychodidae), the established vector for kala-azar is presently being controlled by indoor residual spray of DDT in kala-azar endemic areas in India. Search for non-hazardous and non-toxic biodegradable active molecules from botanicals may provide cost-effective and eco-friendly alternatives to synthetic insecticides. The present study was aimed at evaluating various plant extracts from endemic and non-endemic areas of Bihar for their insecticidal activity against sandfly to identify the most effective plant extract.
Bio-assay test was conducted with larvae and adult of P. argentipes with different plant extracts collected in distilled water, hexane, ethyl acetate, acetone and methanol. Thin layer chromatography (TLC), column chromatography and high performance liquid chromatography (HPLC) were conducted for detection of active molecules.
Adults and larvae of sandflies exposed to the aqueous extract of Nicotiana tabacum resulted in 100 per cent mortality. The hexane extract of Clerodendrum infortunatum was found to kill 77 per cent adults but was ineffective against larvae. Bio-assay test of the ninth fraction (hexane extract-methanol phase) separated by column chromatography was found to be 63 per cent effective. The purple spot on the TLC of this fraction indicated the presence of a diterpenoid. HPLC of this fraction detected nine compounds with two peaks covering 20.44 and 56.52 per cent areas with retention time of 2.439 and 5.182 min, respectively supporting the TLC results.
INTERPRETATION & CONCLUSIONS: The column separated 9 [th] fraction of C. infortunatum extract was found to be effective in killing 63 per cent of adult P. argentipes. Compounds of this fraction need to be evaluated further for identification and characterization of the active molecule by conducting individual bio-assay tests followed by further fractionation and HPLC. Once the structure of the active molecule is identified and validated, it may be synthesized and formulated as a product.
银足白蛉（双翅目：毛蠓科）是黑热病的既定传播媒介，目前印度黑热病流行地区通过室内喷洒滴滴涕进行控制。从植物中寻找无害、无毒且可生物降解的活性分子，可能为合成杀虫剂提供具有成本效益且环保的替代品。本研究旨在评估比哈尔邦流行和非流行地区的各种植物提取物对白蛉的杀虫活性，以确定最有效的植物提取物。
用收集于蒸馏水、己烷、乙酸乙酯、丙酮和甲醇中的不同植物提取物对白蛉的幼虫和成虫进行生物测定试验。进行薄层色谱（TLC）、柱色谱和高效液相色谱（HPLC）以检测活性分子。
暴露于烟草水提取物的白蛉成虫和幼虫死亡率达100%。发现臭牡丹的己烷提取物可杀死77%的成虫，但对幼虫无效。柱色谱分离出的第九部分（己烷提取物 - 甲醇相）的生物测定试验显示其有效性为63%。该部分TLC上的紫色斑点表明存在一种二萜类化合物。该部分的HPLC检测到9种化合物，两个峰分别覆盖面积的20.44%和56.52%，保留时间分别为2.439分钟和5.182分钟，支持了TLC结果。
发现柱分离的臭牡丹提取物第九部分对63%的银足白蛉成虫有效。该部分的化合物需要进一步评估，通过进行单独的生物测定试验，随后进一步分离和HPLC来鉴定和表征活性分子。一旦活性分子的结构被鉴定和验证，就可以进行合成并制成产品。
