Plant extracts serve as reducing and coating agents and are, therefore, commonly employed for the generation of silver (Ag) nanoparticles (NPs). Plant extract mediated synthesis of Ag NPs is a green, environmentally friendly and cost-effective technique which offers a new and potential alternative to chemically synthesized NPs, decreasing the utilization of hazardous and toxic chemicals and protecting the environment. Origanum vulgare L. extracts were evaluated for total flavonoid and phenol content. The free radical scavenging activity was determined employing 2,2-diphenyl-1-picrylhydrazyl assay. Ag NPs were produced exploiting ethanolic extracts of O. vulgare L. leaves. The generation of Ag NPs was carried out both in light and dark conditions. The biosynthesized Ag NPs were characterized employing microscopic and spectroscopic techniques. Antibacterial activities of Ag NPs were determined following appropriate methods. The results revealed that energy of photons was required to reduce Ag⁺ to Ag⁰. According to scanning electron microscopy reports, biologically formed Ag NPs ranged in size from 1 to 50 nmand were presented instability causing aggregation. They indicated that O. vulgare L. extracts were rich in flavonoids and phenols and exhibited strong antioxidant activity. Ag NPs exhibited good antibacterial activity immediately after production. Gram-positive strains showed higher sensitivity to Ag NPs compared to Gram-negative stains. Ag NPs can serve as an effective antibacterial agent against antibiotic-resistant strains. The kanamycin-resistant strain was more sensitive to Ag NPs than the ampicillin-resistant strain. Thus, Origanum extract-mediated synthesized Ag NPs can be recommended as alternative effective antibacterial agents, but their activity depended on bacterial species and strains.

中文翻译：

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牛至提取物介导的银纳米粒子的合成，其表征和抗菌活性。

植物提取物用作还原剂和包衣剂，因此通常用于生成银（Ag）纳米颗粒（NPs）。植物提取物介导的Ag NP的合成是一种绿色，环保且具有成本效益的技术，它为化学合成NP提供了一种新的潜在替代方法，从而减少了有害和有毒化学物质的利用并保护了环境。评价了牛至属植物提取物的总类黄酮和苯酚含量。使用2，2-二苯基-1-吡咯肼基测定法测定自由基清除活性。Ag NPs是利用普通小麦的乙醇提取物生产的L.叶子。Ag NP的生成是在明暗条件下进行的。利用显微镜和光谱技术对生物合成的银纳米颗粒进行了表征。Ag NPs的抗菌活性是按照适当的方法确定的。结果表明，需要光子能量才能将Ag ⁺还原为Ag ⁰。根据扫描电子显微镜报告，生物形成的Ag NPs的大小范围为1至50 nm，并且存在不稳定的现象，会引起聚集。他们表示，O。vulgareL.提取物富含类黄酮和酚，并表现出强大的抗氧化活性。Ag NP在生产后立即显示出良好的抗菌活性。与革兰氏阴性菌相比，革兰氏阳性菌对Ag NPs的敏感性更高。Ag NPs可以作为有效的抗抗生素菌株的抗菌剂。耐卡那霉素的菌株比耐氨苄青霉素的菌株对Ag NPs更敏感。因此，牛至提取物介导的合成银纳米颗粒可以被推荐作为替代的有效抗菌剂，但是它们的活性取决于细菌的种类和菌株。