Green synthesis of gold nanoparticles using seed aqueous extract of Abelmoschus esculentus and its antifungal activity

In the present work, we describe the synthesis of gold nanoparticles (Au NPs) using seed aqueous extract of Abelmoschus esculentus and its antifungal activity. UV–visible spectroscopy, XRD, FTIR, AFM, FESEM and EDX analyses were performed to ascertain the formation of Au NPs. The synthesized Au NPs were characterized by a peak at 536 nm in the UV–visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 62 nm size. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (1 1 1), (2 0 0), (2 2 0) and (3 1 1) Bragg's reflections of cubic structure of metallic gold, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. AFM shows the 3D topological characteristic of Au NPs. FESEM images revealed that all particles were spherical with a narrow size range of 45–75 nm. Antifungal activity of Au NPs were tested against Puccinia graminis tritci, Aspergillus flavus, Aspergillus niger and Candida albicans using standard well diffusion method. The maximum zone of inhibition was observed in the Au NPs against P. graminis (17 mm) and C. albicans (18 mm). The results suggest that the synthesized Au NPs act as an effective antifungal agent. It is confirmed that Au NPs are capable of rendering high antifungal efficacy and hence has a great potential in the preparation of drugs used against fungal diseases.

Graphical abstractSynthesis of gold nanoparticles (Au NPs) using Abelmoschus esculentus seed extract as reducing and capping agent. The synthesized NPs were characterized by a peak at 536 nm in the UV–visible spectrum. XRD confirmed the crystalline nature of the nanoparticle of 62 nm size. FESEM images displays that all particles are spherical with a very narrow size distribution. AFM finds the topological appearance and the size range was found to be 45–75.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Abelmoschus esculentus seed aqueous extract was utilized to synthesis Au NPs. ► The UV peak was practical at 536 nm which is typical to polydisperse nanoparticles. ► XRD confirmed the crystalline nanoparticles of 62 nm size. ► FESEM images display spherical shape of the synthesized NPs. ► Au NPs had significant antifungal activity.