In this study, we report on the biosynthesis of gold nanoparticles (AuNPs) by using Callistemon citrinus (C. citrinus) seed extract as both reducing and capping agent as well as its characterization. Likewise, the in vitro antiparasitic activities of both biosynthesized gold nanoparticles and crude seed extract of the plant were evaluated. The formation of biosynthesized AuNPs was confirmed by a color change immediately when the seed extract was added to the gold chloride (III) solution. Characterization of the AuNPs was done using analytical tools like ultraviolet–visible spectroscopy, X–ray diffraction, scanning electron microscopy (SEM), energy dispersive X–ray (EDX), transmission electron microscopy (TEM) and Fourier transformed infra–red (FTIR). FTIR showed an absorption peak at 230 nm consistent with the absorption band for gold nanoparticles, the morphology and composition of AuNPs was ascertained by SEM and EDX micrographs; uneven spherical-shaped nanoparticles was established by SEM analysis, and an average particle size of about 37 nm was confirmed by the TEM analysis. The crude seed extracts exhibited antitrypanosoma activities with an IC50 of 11.06 µg/mL. Both the crude seed extract and AuNPs were inactive against plasmodial parasite, while the antibacterial assay showed that AuNPs is potent against gram positive and gram negative bacterial strains.

在这项研究中，我们报道了使用柑桔Callistemon citrinus（C. citrinus）种子提取物作为还原剂和加帽剂对金纳米颗粒（AuNPs）的生物合成及其表征。同样，体外评价了生物合成的金纳米颗粒和植物的粗种子提取物的抗寄生虫活性。当将种子提取物添加到氯化金（III）溶液中时，立即通过颜色变化确认了生物合成AuNP的形成。AuNPs的表征使用紫外可见光谱，X射线衍射，扫描电子显微镜（SEM），能量色散X射线（EDX），透射电子显微镜（TEM）和傅立叶变换红外（FTIR）等分析工具完成）。FTIR显示在230nm处有一个吸收峰，与金纳米颗粒的吸收带一致，通过SEM和EDX显微照片确定了AuNP的形态和组成。通过SEM分析建立了不均匀球形纳米颗粒，通过TEM分析确认平均粒径为37nm左右。粗种子提取物表现出抗锥虫活性，IC50为11.06 µg / mL。粗种子提取物和AuNPs均对疟原虫无活性，而抗菌检测表明AuNPs对革兰氏阳性和革兰氏阴性细菌均有效。