Biosynthesis of Silver Nanoparticles Using Cucumis prophetarum Aqueous Leaf Extract and Their Antibacterial and Antiproliferative Activity Against Cancer Cell Lines

Abstract

Biosynthesized nanoparticles are gaining attention because of biologically active plant secondary metabolites that help in green synthesis and also due to their unique biological applications. This study reports a facile, ecofriendly, reliable, and cost-effective synthesis of silver nanoparticles using the aqueous leaf extract of Cucumis prophetarum (C. prophetarum) and their antibacterial and antiproliferative activity. Silver nanoparticles were biosynthesized using the aqueous leaf extract of C. prophetarum, which acted as a reducing and capping agent. The biosynthesized C. prophetarum silver nanoparticles (Cp-AgNPs) were characterized using different techniques, such as UV-visible spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). Phytochemical analysis was performed to determine the phytochemicals responsible for the reduction and capping of the biosynthesized Cp-AgNPs. The antioxidant activity of the biosynthesized nanoparticles was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Their antibacterial activity was checked against Staphylococcus aureus (Gram-positive) and Salmonella typhi (Gram-negative) bacteria. The biosynthesized nanoparticles showed dosage-dependent inhibition activity with a significant zone of inhibition and were more effective toward S. typhi as compared to S. aureus. Their antiproliferative activity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on selected cancer cell lines. The IC₅₀ values of Cp-AgNPs on A549, MDA-MB-231, HepG2, and MCF-7 were found to be 105.8, 81.1, 94.2, and 65.6 μg/mL, respectively, and this showed that the Cp-AgNPs were more potent toward MCF-7 as compared to other cell lines used in this study. This work revealed that the biosynthesized silver nanoparticles using C. prophetarum leaf extract were associated with good antibacterial activity and antiproliferative potential against selected cancer cell lines. The biosynthesized C. prophetarum AgNPs can be further exploited as a potential candidate for antioxidant, antibacterial, and anticancer agents.

Figure 1

Biosynthesis of silver nanoparticles: (A) color change of the extract from pale yellow to dark brown after incubation at room temperature (RT); (B) UV spectra of the aqueous leaf extract and Cp-AgNPs synthesized from the C. prophetarum leaf extract.

Figure 2

Nanoparticle size measurements: (A) size and PDI analysis; (B) ζ-potential of the biosynthesized Cp-AgNPs.

Figure 3

FTIR spectra of the C. prophetarum leaf extract (red) and Cp-AgNPs (blue) synthesized from the leaf extract.

Figure 4

XRD pattern of the synthesized Cp-AgNPs using C. prophetarum leaf extract.

Figure 5

Electron microscopy study: (A) SEM analysis and (B) EDX spectra of Cp-AgNPs.

Figure 6

Free radical scavenging activity of different concentrations of the aqueous leaf extract of C. prophetarum and Cp-AgNPs using (A) DPPH scavenging effect and (B) ABTS assay.

Figure 7

Bactericidal activity of different concentrations of (A) aqueous extract and (B) Cp-AgNPs against S. aureus and (C) aqueous extract and (D) Cp-AgNPs against S. typhi.

Figure 8

Effect of different concentrations of Cp-AgNPs on the viability of human cancer cell lines. One-way analysis of variance (ANOVA) multiple comparisons; ****P-value signifies < 0.0001, ***P-value signifies < 0.001, **P-value signifies < 0.01, and *P-value signifies < 0.05.

Figure 9

Morphology at the IC₅₀ concentration of Cp-AgNPs of cancer cell lines (A) A549, (B) MDA-MB-231, (C) HepG2, and (D) MCF-7.