Unit of Nanotechnology and Bioactive Natural Products, Post Graduate and Research Department of Zoology, C. Abdul Hakeem College, Melvisharam, 632 509, Vellore District, Tamil Nadu, India.
Parasitol Res. 2012 Sep;111(3):1369-78. doi: 10.1007/s00436-011-2559-1. Epub 2011 Jul 26.
The use of acaricides had limited efficacy in reducing tick infestations and is often accompanied by serious drawbacks, including the selection of acaricide resistant ticks, contamination of environment, and milk and meat products with drug residues. The present study was based on assessments of the antiparasitic activities to determine the efficacy of synthesized silver nanoparticles (AgNPs) utilizing aqueous leaf extract of Ocimum canum Sims (Labiatae) against the larvae of Hyalomma anatolicum (a.) anatolicum Koch, 1844 and Hyalomma marginatum (m.) isaaci Sharif, 1928 (Acari: Ixodidae). The synthesized AgNPs results were recorded from UV-vis spectrum, X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The production of the AgNPs synthesized from the leaf extract of O. canum was evaluated through UV-visible spectrophotometer in a range of wavelength from 300 to 600 nm. This revealed a peak at 426 nm in leaf extracts of O. canum, indicating the production of AgNPs. The XRD spectrum compared with the standard confirmed spectrum of silver particles formed in the present experiments were in the form of nanocrystals, as evidenced by the peaks at 2θ values of 27.71°, 32.16°, 38.08°, 46.15°, 54.70° and 57.35°. The FTIR spectra of AgNPs exhibited prominent peaks at 818, 1,045, 1,381 and 1,616 in the region 500-3,000 cm(-1). The peaks correspond to the presence of a C-H vibration of the aromatic ring, stretch vibration of C-O, carbonyl groups and flavanones. SEM analyses of the synthesized AgNPs were clearly distinguishable, which measured 25-110 nm in size. It is clear that the rod and cylindrical structures have an average size of 95 nm. The EDX spectra showed the purity of the material and the complete chemical composition of the synthesized AgNPs. Parasite larvae were exposed to varying concentrations of aqueous leaf extract of O. canum and synthesized AgNPs for 24 h. The acaricidal activities of aqueous crude leaf extracts of O. canum against the larvae of H. a. anatolicum and H. m. isaaci have LC(50) and LC(90) values of 15.31 and 13.85 mg/L, and 62.41 and 48.86 mg/L, respectively. The efficacies of 1 mM AgNO(3) solution against H. a. anatolicum and H. m. isaaci were LC(50) = 12.25 and 12.17 mg/L, LC(90) = 49.17 and 46.52 mg/L, respectively, and the maximum efficacy was observed in the synthesized AgNPs against H. a. anatolicum and H. m. isaaci with LC(50) and LC(90) values of 0.78 and 1.00 mg/L, and 1.51 and 1.68 mg/L, respectively. This method is considered as an innovative alternative approach to control parasites.
本研究基于评估驱虫活性，以确定利用 Ocimum canum Sims（唇形科）叶水提物合成的银纳米粒子（AgNPs）对 Hyalomma anatolicum（a.）anatolicum Koch，1844 和 Hyalomma marginatum（m.）isaaci Sharif，1928（蜱螨目：Ixodidae）幼虫的疗效。AgNPs 的合成结果从紫外可见光谱、X 射线衍射（XRD）分析、傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）和能谱（EDX）分析中记录。通过在 300-600nm 波长范围内的紫外可见分光光度计评估了从 O. canum 叶提取物中合成的 AgNPs 的产生。这在 O. canum 叶提取物中显示出 426nm 的峰值，表明 AgNPs 的产生。XRD 光谱与标准银粒子形成的标准光谱进行比较，证实了在本实验中形成的纳米晶体形式的颗粒，这一点可以从 2θ 值为 27.71°、32.16°、38.08°、46.15°、54.70°和 57.35°的峰得到证明。AgNPs 的 FTIR 光谱在 500-3000cm（-1）区域显示出 818、1045、1381 和 1616nm 处的明显峰值。这些峰对应于芳香环的 C-H 振动、C-O 的伸缩振动、羰基和黄烷酮的存在。合成 AgNPs 的 SEM 分析清晰可辨，大小为 25-110nm。很明显，棒状和圆柱形结构的平均尺寸为 95nm。EDX 光谱显示了材料的纯度和合成 AgNPs 的完全化学成分。寄生虫幼虫暴露于不同浓度的 O. canum 叶水提物和合成 AgNPs 24 小时。O. canum 叶水提物对 H. a. anatolicum 和 H. m. isaaci 幼虫的杀螨活性的 LC（50）和 LC（90）值分别为 15.31 和 13.85mg/L，62.41 和 48.86mg/L。1mM AgNO（3）溶液对 H. a. anatolicum 和 H. m. isaaci 的功效分别为 LC（50）= 12.25 和 12.17mg/L，LC（90）= 49.17 和 46.52mg/L，而合成 AgNPs 对 H. a. anatolicum 和 H. m. isaaci 的最大功效为 LC（50）和 LC（90）值分别为 0.78 和 1.00mg/L，1.51 和 1.68mg/L。这种方法被认为是控制寄生虫的一种创新替代方法。
