Biomolecules and Genetics Division, School of Biosciences and Technology, VIT University, Vellore, 632 014, Tamil Nadu, India.
Parasitol Res. 2013 Jan;112(1):215-26. doi: 10.1007/s00436-011-2682-z. Epub 2011 Oct 19.
The aim of the present study was to assess the larvicidal property of marine actinobacterial compound 5-(2,4-dimethylbenzyl) pyrrolidin-2-one (DMBPO) extracted and isolated from Streptomyces VITSVK5 sp. tested against the larvae of Rhipicephalus (Boophilus) microplus Canestrini (Acari: Ixodidae), Anopheles stephensi Liston, and Culex tritaeniorhynchus Giles (Diptera: Culicidae). The isolate bacteria was taxonomically characterized, identified, and designated as Streptomyces VITSVK5 sp. The crude extract was loaded on silica gel column and eluted with chloroform:methanol. The isolated pure compound was analyzed by thin layer chromatography using chloroform and methanol as the solvent system and confirmed by high-performance liquid chromatography. The structure of the purified compound was established from infrared, ultraviolet, (1)H-nuclear magnetic resonance (NMR), (13)C-NMR, and mass spectral data. The chemical shift assignments obtained for the aliphatic compound from (1)H-NMR corresponding to the molecular formula C(13)H(17)NO. Bioassay-guided fractionation led to the isolation of compound which was identified as DMBPO. In the present study, Streptomyces VITSVK5 sp. crude extract and different fractions were tested against the larvae of parasites at the concentration of 1,000 ppm. Those fractions showing 100% mortality in 24 h alone was selected for further column chromatographic separation. The purified compound, C(13)H(17)NO, was tested in the concentrations of 500, 250, 125, 62.5, and 31.25 ppm and observed the percent larval mortality of 100, 70, 64, 40, and 28 against R. microplus; 100, 79, 63, 36, and 22 against A. stephensi; and 100, 84, 67, 42, and 27 against C. tritaeniorhynchus, respectively. The crude extract showed parasitic effects after 24 h of exposure at 1,000 ppm, and parasite mortality was observed against the larvae of R. microplus (LC(50) = 210.39 ppm, r (2) = 0.873); A. stephensi (LC(50) = 169.38 ppm, r (2) = 0.840); and C. tritaeniorhynchus (LC(50) = 198.75 ppm, r (2) = 0.887). The maximum efficacy was observed in purified marine actinobacterial compound DMBPO with LC(50) and r (2) values against the larvae of R. microplus (84.31 ppm, 0.889); A. stephensi (88.97 ppm, 0.817), and C. tritaeniorhynchus (74.95 ppm, 0.781), respectively. The control (distilled water) showed nil mortality in the concurrent assay.
本研究旨在评估从海洋放线菌菌株 Streptomyces VITSVK5 中提取和分离得到的化合物 5-(2,4-二甲基苄基)吡咯烷-2-酮 (DMBPO) 的杀幼虫特性，该化合物针对 Rhipicephalus (Boophilus) microplus Canestrini (蜱螨目: 硬蜱科)、Anopheles stephensi Liston 和 Culex tritaeniorhynchus Giles (双翅目: 蚊科)的幼虫进行了测试。分离的细菌经过分类学鉴定、鉴定，并被命名为 Streptomyces VITSVK5 sp。粗提取物加载到硅胶柱上，用氯仿:甲醇洗脱。分离的纯化合物通过薄层色谱法用氯仿和甲醇作为溶剂系统进行分析，并通过高效液相色谱法进行确认。通过红外、紫外、(1)H-核磁共振 (NMR)、(13)C-NMR 和质谱数据确定了纯化化合物的结构。从(1)H-NMR 中获得的脂肪化合物的化学位移分配对应于分子式 C(13)H(17)NO。基于生物活性的分步分离导致分离出的化合物被鉴定为 DMBPO。在本研究中，Streptomyces VITSVK5 sp. 粗提取物和不同馏分以 1000 ppm 的浓度对寄生虫幼虫进行了测试。那些在 24 小时内显示出 100%死亡率的馏分被单独选择用于进一步的柱色谱分离。测试了纯化化合物 C(13)H(17)NO 在 500、250、125、62.5 和 31.25 ppm 的浓度下，对 R. microplus 的幼虫死亡率分别为 100%、70%、64%、40%和 28%；对 A. stephensi 的幼虫死亡率分别为 100%、79%、63%、36%和 22%；对 C. tritaeniorhynchus 的幼虫死亡率分别为 100%、84%、67%、42%和 27%。粗提取物在 1000 ppm 浓度下暴露 24 小时后表现出寄生虫效应，对 R. microplus 的幼虫死亡率为 50.39 ppm (LC(50)，r(2) = 0.873)；A. stephensi 的幼虫死亡率为 169.38 ppm (LC(50)，r(2) = 0.840)；C. tritaeniorhynchus 的幼虫死亡率为 198.75 ppm (LC(50)，r(2) = 0.887)。纯化的海洋放线菌化合物 DMBPO 表现出最大的功效，对 R. microplus 的幼虫的 LC(50)和 r(2)值分别为 84.31 ppm (0.889)；A. stephensi 的幼虫的 LC(50)和 r(2)值分别为 88.97 ppm (0.817)；C. tritaeniorhynchus 的幼虫的 LC(50)和 r(2)值分别为 74.95 ppm (0.781)。对照（蒸馏水）在平行试验中无死亡率。
