Centre for Plant Sciences and Biodiversity, University of Swat, Charbagh 19120, Khyber Pakhtunkhwa, Pakistan.
Centre for Biotechnology and Microbiology, University of Swat, Charbagh 19120, Khyber Pakhtunkhwa, Pakistan.
Molecules. 2022 May 30;27(11):3525. doi: 10.3390/molecules27113525.
Biologically synthesized silver nanoparticles are emerging as attractive alternatives to chemical pesticides due to the ease of their synthesis, safety and antimicrobial activities in lower possible concentrations. In the present study, we have synthesized silver nanoparticles (AgNPs) using the aqueous extract of the medicinal plant and tested them against the plant pathogenic bacterium , the causative agent of citrus canker, via an in vitro experiment. The synthesized silver nanoparticles were characterized by techniques such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis and transmission electron microscopy. Moreover, the plant species were investigated for phenolics, flavonoids and antioxidant activity. The antioxidant potential of the extract was determined against a DPPH radical. The extract was also evaluated for phenolic compounds using the HPLC technique. The results confirmed the synthesis of centered cubic, spherical-shaped and crystalline nanoparticles by employing standard characterization techniques. A qualitative and quantitative phytochemical analysis revealed the presence of phenolics (41.52 mg GAE/g), flavonoids (14.2 mg QE/g) and other metabolites of medicinal importance. Different concentrations (1000 µg/mL to 15.62 µg/mL-2 fold dilutions) of AgNPs and plant extract (PE) alone, and both in combination (AgNPs-PE), exhibited a differential inhibition of in a high throughput antibacterial assay. Overall, AgNPs-PE was superior in terms of displaying significant antibacterial activity, followed by AgNPs alone. An appreciable antioxidant potential was recorded as well. The observed antibacterial and antioxidant potential may be attributed to eight phenolic compounds identified in the extract. The leaf-extract-induced synthesized AgNPs exhibited strong antibacterial activity against , which could be exploited as effective alternative preparations against citrus canker in planta in a controlled environment. In addition, as a good source of phenolic compounds, the plant could be further exploited for potent antioxidants.
生物合成的银纳米粒子由于其易于合成、安全性高以及在较低浓度下具有抗菌活性，成为化学农药的有吸引力的替代品。在本研究中，我们使用药用植物的水提物合成了银纳米粒子（AgNPs），并通过体外实验测试了它们对植物病原菌的抗菌活性，该病原菌是柑橘溃疡病的病原体。合成的银纳米粒子通过紫外可见光谱、傅里叶变换红外光谱、能谱、X 射线衍射分析和透射电子显微镜等技术进行了表征。此外，还对植物物种进行了酚类、类黄酮和抗氧化活性的研究。使用 DPPH 自由基测定了提取物的抗氧化潜力。还使用 HPLC 技术评估了提取物中的酚类化合物。结果证实，采用标准表征技术，合成了中心立方、球形和结晶纳米粒子。定性和定量的植物化学分析表明，存在具有药用重要性的酚类（41.52mgGAE/g）、类黄酮（14.2mgQE/g）和其他代谢物。不同浓度（1000µg/mL 至 15.62µg/mL-2 倍稀释）的 AgNPs 和植物提取物（PE）单独使用，以及两者联合使用（AgNPs-PE），在高通量抗菌测定中表现出不同程度的抑制作用。总体而言，AgNPs-PE 在显示出显著的抗菌活性方面表现更为出色，其次是单独的 AgNPs。同时还记录了相当大的抗氧化潜力。观察到的抗菌和抗氧化潜力可能归因于提取物中鉴定出的八种酚类化合物。叶提取物诱导合成的 AgNPs 对表现出很强的抗菌活性，可作为在受控环境下防治柑橘溃疡病的有效替代制剂。此外，作为酚类化合物的良好来源，该植物可进一步开发为有效的抗氧化剂。
