Department of Biosciences, Integral University, Lucknow, India.
School of Biotechnology, IFTM University, Moradabad, India.
Life Sci. 2018 Sep 15;209:430-434. doi: 10.1016/j.lfs.2018.08.046. Epub 2018 Aug 20.
Silver nanoparticles (AgNPs) have been used in various medicinal and commercial products because of their exceptional anti-microbial and anti-odor properties. On the other hand, increased commercialization of AgNPs containing products has led to its release into the environment. Thus, studies are needed to assess their impact on the environment as well as on human body. Several reports have shown that AgNPs could cause some serious neurotoxic effects. Most of these studies have been performed using chemically synthesized AgNPs. In contrast, green nanoparticles are usually considered safer than their chemically synthesized counterparts. Accordingly, in this research work, we have assessed the effect of AgNPs synthesized from aqueous-leaf-extract of Mentha piperita on one of the most important neurological enzymes i.e. acetylcholinesterase (AChE) to predict its neurotoxicity. M. piperita synthesized AgNPs were subjected to characterization by UV-visible-spectrometry, Scanning Electron-Microscopy as well as Transmission Electron-Microscopy. Here, the size of the AgNPs was found to be 35 nm with spherical shape. These AgNPs showed concentration-dependent inhibitory-effect on the AChE enzyme-activity displaying an IC of 150 nM. Further, kinetic analysis showed mixed type of inhibition, which means that AgNPs were capable of binding to both the free enzyme (AChE) and to the enzyme-substrate (AChE-acetylcholine) complex. These results suggest that even green synthesized AgNPs might cause neurotoxicity via inhibiting AChE activity. However, more studies are needed to elucidate the exact mechanism of neurotoxicity by AgNPs. Nevertheless, we could safely state that the present study provides relevant preliminary information regarding neurotoxicity of green synthesized AgNPs.
纳米银颗粒（AgNPs）因其具有出色的抗菌和除臭性能，已被广泛应用于各种医药和商业产品中。另一方面，含有 AgNPs 的产品商业化程度的提高导致其被释放到环境中。因此，需要研究其对环境以及人体的影响。有几项报告表明，AgNPs 可能会引起一些严重的神经毒性作用。这些研究大多使用化学合成的 AgNPs 进行。相比之下，绿色纳米颗粒通常被认为比其化学合成的对应物更安全。因此，在这项研究工作中，我们评估了从 Mentha piperita 的水提叶提取物合成的 AgNPs 对一种最重要的神经酶，即乙酰胆碱酯酶（AChE）的影响，以预测其神经毒性。用紫外可见分光光度法、扫描电子显微镜和透射电子显微镜对 M. piperita 合成的 AgNPs 进行了表征。结果发现，AgNPs 的尺寸为 35nm，呈球形。这些 AgNPs 对 AChE 酶活性表现出浓度依赖性抑制作用，IC 为 150nM。进一步的动力学分析表明，AgNPs 具有混合抑制类型，这意味着 AgNPs 能够与游离酶（AChE）和酶-底物（AChE-乙酰胆碱）复合物结合。这些结果表明，即使是绿色合成的 AgNPs 也可能通过抑制 AChE 活性引起神经毒性。然而，需要进一步的研究来阐明 AgNPs 引起神经毒性的确切机制。尽管如此，我们可以有把握地说，本研究为绿色合成的 AgNPs 的神经毒性提供了相关的初步信息。
