Plumeria alba-Mediated Green Synthesis of Silver Nanoparticles Exhibits Antimicrobial Effect and Anti-Oncogenic Activity against Glioblastoma U118 MG Cancer Cell Line

Abstract

Plumeria alba (P. alba) is a small laticiferous tree with promising medicinal properties. Green synthesis of nanoparticles is eco-friendly, cost-effective, and non-hazardous compared to chemical and physical synthesis methods. Current research aiming to synthesize silver nanoparticles (AgNPs) from the leaf extract of P. alba (P- AgNPs) has described its physiochemical and pharmacological properties in recognition of its therapeutic potential as an anticancer and antimicrobial agent. These biogenic synthesized P-AgNPs were physiochemically characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), and zeta potential analyses. Antimicrobial activity was investigated against Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Enterococcus faecalis, Bacillus subtilis, Streptococcus pneumoniae, Candida albicans, and Candida glabrata. Anticancer activity against glioblasoma U118 MG cancer lines was investigated using an MTT assay, and apoptosis activity was determined by flow cytometry. UV–visible spectroscopic analysis portrayed surface plasmon resonance at 403 nm of synthesized P-AgNPs, and FTIR suggested the presence of amines, alkanes, and phenol molecules that could be involved in reduction and capping processes during AgNPs formation. Synthesized particles were spherical in shape and poly-dispersed with an average particle size of 26.43 nm and a poly-dispersity index (PDI) of 0.25 with a zeta potential value of −24.6 mV, ensuring their stability. The lattice plane values confirm the crystalline nature as identified by XRD. These P-AgNPs exhibited potential antimicrobial activity against selected human pathogenic microbes. Additionally, the in vitro MTT assay results show its effective anticancer activity against the glioma U118 MG cancer cell line with an IC50 value of 9.77 µg/mL AgNPs by initiating apoptosis as identified by a staining study with flow cytometric annexin V–fluorescein isothiocyanate (FITC) and propidium iodide (PI). Thus, P. alba AgNPs can be recommended for further pharmacological and other biological research. To conclude, the current investigation developed an eco-friendly AgNPs synthesis using P. alba leaf extract with potential cytotoxic and antibacterial capacity, which can therefore be recommended as a new strategy to treat different human diseases.

Green Synthesis of Silver Nanoparticles Using Randia aculeata L. Cell Culture Extracts, Characterization, and Evaluation of Antibacterial and Antiproliferative Activity

“…On the other hand, based on inhibition zone assays, AgNPs (7–14 nm) synthesized using Thuja occidentalis leaf extracts were found to have inhibitory effect against S. aureus and E. coli at 40 µL of plant extract/nanoparticles, while leaf extracts were not effective [ 71 ]. By using AgNPs synthesized with extracts of Plumeria alba , it was found that they showed good antibacterial activity at concentrations of 25–100 µg/mL in terms of zone of inhibition, in which large zones of inhibition were observed mainly for Streptococcus pneumoniae (16 mm) at 100 µg/mL [ 72 ]. Similarly, other studies report obtaining AgNPs (approximately 15 nm in diameter) using waste material (dry grass), demonstrating activity against P. aeruginosa and Acinetobacter baumannii with a MIC = 3 µg/mL of AgNPs [ 73 ].…”

Antifungal activity of silver nanoparticles prepared using Aloe vera extract against Candida albicans

“…In Figure-6 , the XRD pattern presents diffraction peaks at 27.90, 32.23, 46.29, and 54.91, corresponding to lattice plane values recorded at (111), (200), (220), and (311) of Ag crystals, respectively. The obtained peaks in the XRD pattern clearly explained that the Ag + ions had been completely reduced to Ag 0 by the reducing and stabilization compounds in the aqueous extract under reaction conditions [ 32 ]. There were some unassigned peaks in the chromatogram.…”

“…There were some unassigned peaks in the chromatogram. The presence of sharp peaks in the chromatogram indicated proteins or some bioorganic compounds in the NPs during synthesis [32]. Similar results of crystalline were reported by Rudrappa et al [32] on Plumeria alba-mediated AgNPs with XRD spectrum pattern that showed distinct diffraction peaks at 2θ angles of 38.19°, 44.37°, 64.77°, and 76.39°, indexed to the (111), ( 200), (220), and (311) Bragg's reflection of the face-centered cubic structure of Ag crystals, confirming their highly crystalline nature [32].…”

“…The presence of sharp peaks in the chromatogram indicated proteins or some bioorganic compounds in the NPs during synthesis [32]. Similar results of crystalline were reported by Rudrappa et al [32] on Plumeria alba-mediated AgNPs with XRD spectrum pattern that showed distinct diffraction peaks at 2θ angles of 38.19°, 44.37°, 64.77°, and 76.39°, indexed to the (111), ( 200), (220), and (311) Bragg's reflection of the face-centered cubic structure of Ag crystals, confirming their highly crystalline nature [32]. In another work by Krishna et al [33], AgNPs from a leaf extract of Sansevieria roxburghiana showed peaked values at 38°, 44°, 64°, and 77°, confirming the crystalline face-centered cubic nature.…”

Antimicrobial activity of the methanolic leaf extract of Prosopis laevigata

“…One of the main research directions to combat this problem has focused on the search for novel molecules that can complement or replace the antibiotics that are currently used and have lost their effectiveness over time 2 , 4 . A great number of these investigations explore secondary metabolites from fungi, plants, and animals for this purpose, sometimes using traditional medicine as a starting point to identify compounds of interest 5 – 7 .…”