Abstract

The present work reports on the antibacterial and antioxidant activity of gold and silver nanoparticles, synthesized by an extract of the brown macroalga Sargassum muticum (SM). These nanoparticles were synthesized and fully characterized by means of UV–Vis spectroscopy and electron microscopy. These techniques confirmed that spherical nanoparticles, with mean diameters of 10.4 ± 1.2 nm for Au@SM and 41.0 ± 5.7 nm for Ag@SM, were formed. To investigate the possible role of these biomolecules in this green synthetic process, Fourier-transformed infrared spectroscopy analysis was performed before and after the synthesis of nanoparticles. Furthermore, the carbohydrate composition was examined along with other variations observed after the synthesis of nanoparticles by size-exclusion chromatography. The study of the changes observed indicated that the polysaccharide fraction of the extract plays a role in the formation of the nanoparticles as well as in their stabilization. The in vitro antioxidant activity was analyzed by the determination of the reducing power, total content of phenolic compounds and the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) scavenging activity. Lastly, the antibacterial activity was tested against three types of bacteria with different cell wall composition. In particular, Ag@SM showed good inhibitory capacity on Gram+, especially on Staphylococcus aureus with a MIC of 3.38 µg/mL.

Graphic abstract

中文翻译：

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鼠尾草生物分子合成银和金纳米粒子及其抗氧化活性和抗菌性能的评价

摘要

本工作报告了由棕色大型藻类Sargassum muticum的提取物合成的金和银纳米颗粒的抗菌和抗氧化活性。（SM）。这些纳米颗粒已经合成，并通过紫外可见光谱和电子显微镜进行了全面表征。这些技术证实形成了球形纳米颗粒，Au @ SM的平均直径为10.4±1.2 nm，Ag @ SM的平均直径为41.0±5.7 nm。为了研究这些生物分子在这种绿色合成过程中的可能作用，在纳米粒子合成之前和之后进行了傅里叶变换红外光谱分析。此外，检查了碳水化合物的组成以及在通过尺寸排阻色谱法合成纳米颗粒之后观察到的其他变化。对所观察到的变化的研究表明，提取物的多糖部分在纳米颗粒的形成及其稳定中起作用。通过测定还原力，酚类化合物的总含量和2,2-二苯基-1-吡啶基-肼基（DPPH）的清除活性来分析体外抗氧化活性。最后，测试了对具有不同细胞壁组成的三种类型细菌的抗菌活性。特别是，Ag @ SM对Gram +具有良好的抑制能力，尤其是对金黄色葡萄球菌，MIC为3.38 µg / mL。

图形摘要