Antimicrobial and Cytotoxicity Effects of Synthesized Silver Nanoparticles from Punica granatum Peel Extract

Abstract

To address the growing challenges from drug-resistant microbes and tumor incidence, approaches are being undertaken to phytosynthesize metal nanoparticles, particularly silver nanoparticles, to get remedial measure. In this study, an attempt has been made to utilize a major biowaste product, pomegranate fruit peel (Punica granatum), to synthesize silver nanoparticles. The silver nanoparticles (AgNPs) were synthesized using the aqueous extract of pomegranate peel. The formation of synthesized AgNPs was confirmed through UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) as well as through the change of the colorless aqueous solution to a dark brown solution. Using UV-Vis spectroscopy, the dark brown solution showed a Plasmon resonance band peak at 378 nm in UV-Vis spectroscopy after reacting for 24, 48, and 72 h. The XRD report revealed that the AgNPs had a cubic structure. The TEM and SEM report showed the nanoparticles were equally distributed in the solution, with a spherical shape and size ranging from 20 to 40 nm and with an average particle size of 26.95 nm. EDX imaging also confirmed the presence of AgNPs. The synthesized AgNPs were found to exhibit good antimicrobial effects on Gram-negative and Gram-positive bacteria, particularly the pathogens Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27584), Proteus vulgaris (ATCC 8427), Salmonella typhi (ATCC 14028), Staphylococcus aureus (ATCC 29213), Staphylococcus epidermidis (MTCC 3615), and Klebsiella pneumonia. The cytotoxic effects of AgNPs were also tested against a colon cancer cell line (RKO: ATCC® CRL-2577™), and it was observed that the viabilities were 56% and 61% on days 3 and 5, respectively, with exposure to 12.5 μg of AgNPs. This simple, economic, and eco-friendly method suggests that the AgNPs biosynthesized using pomegranate peel extract may be a novel, potent solution for the development of a drug for colon cancer that also has antibacterial activity.

Keywords: Antibacterial; Anticancer; Phytosynthesis; Pomegranate peel; Silver nanoparticles.

Fig. 1

a 0.l mM of silver nitrate. b Color changes after P. granatum peel extract added

Fig. 2

UV-Vis absorbance spectra of synthesized AgNPs at 48 to 72 h in time intervals

Fig. 3

XRD pattern of synthesized AgNPs from P. granatum peel extract

Fig. 4

TEM image of synthesized AgNPs from P. granatum peel extract

Fig. 5

SEM image of synthesized AgNPs from P. granatum peel extract

Fig. 6

EDX image of synthesized AgNPs from P. granatum peel extract with quantitative analysis

Fig. 7

Antimicrobial effects and zone of inhibition of AgNPs of Gram-negative pathogens (a–c)

Fig. 8

Antimicrobial effects and zone of inhibition of AgNPs of Gram-positive pathogens (d–f)

Fig. 9

Antimicrobial activity of AgNPs against Gram-negative and Gram-positive pathogens

Fig. 10

Cytotoxicity of AgNPs. a Cell proliferation and viability analysis on RKO cells. One-way ANOVA multiple comparisons, ***P < 0.0005. b Apoptosis/necrosis analysis on RKO cells. c RKO cells exposed to different doses of AgNPs