Green Synthesis of Silver Nanoparticles Using the Leaf Extract of the Medicinal Plant, Uvaria narum and Its Antibacterial, Antiangiogenic, Anticancer and Catalytic Properties

Abstract

Silver nanoparticles (AgNPs) made by green synthesis offer a variety of biochemical properties and are an excellent alternative to traditional medications due to their low cost. In the current study, we synthesised AgNPs from the leaf extract of the medicinal plant Uvaria narum, commonly called narumpanal. The nanoparticles were characterised by ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM analysis showed AgNPs are highly crystalline and spherical with an average diameter of 7.13 nm. The outstanding catalytic activity of AgNPs was demonstrated by employing the reduction of 4-nitrophenol to 4-aminophenol. The AgNPs showed antiangiogenic activity in the chick chorioallantoic membrane (CAM) assay. AgNPs demonstrated anticancer activity against Dalton's lymphoma ascites cells (DLA cells) in trypan blue assay and cytotoxicity against three fish cell lines: Oreochromis niloticus liver (onlL; National Repository of Fish Cell Lines, India (NRFC) Accession number-NRFC052) cells, Cyprinus carpio koi fin (CCKF; NRFC Accession number-NRFC007) cells and Cyprinus carpio gill (CyCKG; NRFC Accession number-NRFC064). Furthermore, the AgNPs demonstrated their ability to inhibit pathogenic microorganisms, Staphylococcus aureus, and Escherichia coli. The results from the study displayed green synthesised AgNPs exhibit antiangiogenic activity, cytotoxicity, antimicrobial and catalytic properties, which are crucial characteristics of a molecule with excellent clinical applications.

Keywords: Uvaria narum; antiangiogenic activity; antibacterial activity; anticancer property; catalytic property; silver nanoparticles.

Figure 1

Photograph of Uvaria narum plant.

Figure 2

The colour change observed during MW exposure of AgNO₃ (0.001 M) with U. narum leaf extract (a), UV-Vis spectra showing the effect of MW exposure over time (b) (Concentration of AgNO₃: 0.001 M; MW power: 350 W).

Figure 3

FTIR spectrum of biosynthesised AgNPs.

Figure 4

SEM images of the AgNPs prepared using U. narum leaf extract under different magnifications (A,B).

Figure 5

TEM images of the AgNPs under different magnifications (A–C), particle size histogram (D) and SAED pattern (E).

Figure 6

Time-dependant UV-Vis absorption spectra of NaBH₄ reduction of 4-nirophenol. The graph indicates reduction of nitro-phenolate ion with time interval of 1 min.

Figure 7

CV analysis of leaf extract of U. narum.

Figure 8

Antiangiogenic activity of AgNPs in vitro CAM assay: AgNPs inhibited the development of blood vessels demonstrating the antiangiogenic nature of the nanoparticles (G–I). Phosphate buffer (A–C) and leaf extracts (D–F) were used for comparison. The quantification of the images with respect to length and junction was analysed and represented as mean ± SD (J,K). AgNPs showed a significant reduction in blood vessel length and junction formation (p < 0.05).

Figure 9

Analysis of in vitro cancer cell cytotoxicity of AgNPs (A–E). The quantification of anticancer activity was estimated and represented as bar diagram (F). The green synthesised AgNPs showed significant cytotoxicity against the control group.

Figure 10

Cytoxicity of AgNPs as observed by morphological changes in three fish cell lines: onlL, CCKF and CyCKG. In comparison to plant extract (B,E,H) and control (A,D,G), green produced AgNPs demonstrated greater cytotoxicity (C,F,I) in the three fish cell lines.

Figure 11

AgNPs showed a clear zone of inhibition against E. coli (A) and S. Aureus (C). Kanamycin (positive control) and Uvaria leaf extract were used as controls. The quantification of antimicrobial activity was estimated and represented as bar diagram (B,D).