Green Synthesis and Characterization of Novel Silver Nanoparticles Using Achillea maritima subsp. maritima Aqueous Extract: Antioxidant and Antidiabetic Potential and Effect on Virulence Mechanisms of Bacterial and Fungal Pathogens

Abstract

Novel silver nanoparticles were synthesized based on a simple and non-toxic method by applying the green synthesis technique, using, for the first time, the aqueous extract of an extremophile plant belonging to the Achillea maritima subsp. maritima species. AgNP characterization was performed via UV-Visible, front-face fluorescence spectroscopy, and FTIR and XRD analyses. AgNP formation was immediately confirmed by a color change from yellow to brown and by a surface plasmon resonance peak using UV-Vis spectroscopy at 420 nm. The biosynthesized AgNPs were spherical in shape with a size ranging from approximatively 14.13 to 21.26 nm. The presented silver nanoparticles exhibited strong antioxidant activity following a DPPH assay compared to ascorbic acid, with IC50 values of about 0.089 µg/mL and 22.54 µg/mL, respectively. The AgNPs showed higher antidiabetic capacities than acarbose, by inhibiting both alpha amylase and alpha glucosidase. The silver nanoparticles could affect various bacterial mechanisms of virulence, such as EPS production, biofilm formation and DNA damage. The silver nanoparticles showed no lysozyme activity on the cell walls of Gram-positive bacteria. The AgNPs also had a strong inhibitory effect on the Candida albicans virulence factor (extracellular enzymes, biofilm formation). The microscopic observation showed abnormal morphogenesis and agglomeration of Candida albicans exposed to AgNPs. The AgNPs showed no cytotoxic effect on human cells in an MTT assay. The use of novel silver nanoparticles is encouraged in the formulation of natural antimicrobial and antidiabetic agents.

Comparative Study of Callistemon citrinus (Bottlebrush) and Punica granatum (Pomegranate) Extracts for Sustainable Synthesis of Silver Nanoparticles and Their Oral Antimicrobial Efficacy

“…The wavelength shift gives possible variations in the size of the synthesized samples (Ag-BBE and Ag-PPE). The presence of a single peak occurrence reflects the spherical shape of the nanoparticles [ 35 ]. The successfully formed nanoparticles validate the suitability of the tested plant extracts (BBE and PPE) as capping and reducing agents for the desired green synthesis of the silver nanoparticles.…”

“…A bottom-up approach is an eco-friendly method where green synthesis is utilized. In this method, reduction and oxidation are the primary reactions for producing nanoparticles [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. This environmentally friendly strategy employs less damaging substances to health by utilizing natural resources such as plants (leaf, bark, flower, fruit, and root extracts) and micro-organisms (bacteria, fungi, viruses, and algae) [ 31 , 33 ].…”

“…The foremost benefits of utilizing the green approach are reduced cost, availability, ease of manipulation, and biocompatibility [ 34 ]. Various plant extracts with distinct secondary metabolites, including Achillea maritima [ 35 ], Coriandrum sativum [ 33 ], Symphyti radix [ 36 ], Lavandula angustifolia Mill [ 37 ], Avena fatua L. [ 38 ], Holigarna arnottiana [ 39 ], Pulicaria undulata [ 40 ], and Leucosidea sericea [ 32 ] were recently employed as reducing and capping agents in the environmentally friendly synthesis of Ag nanoparticles.…”

Green Synthesis of Silver Nanoparticles Using Jasminum nudiflorum Flower Extract and Their Antifungal and Antioxidant Activity

“…The presence of aldehyde or ketone functional groups (C=O) from flavonoid and tannin derivatives can be inferred from the peaks at 1617 cm −1 ,1626 cm −1 , 1650 cm −1 , and 1653 cm −1 [ 44 , 47 , 49 ]. While the peak at 1633 cm −1 and 1631 cm −1 signifies C=C stretching vibrations of the hydrocarbon portion of biological double-bond molecules, the band at 1052 cm −1 and 1031 cm −1 may be attributed to C-O stretching [ 35 , 46 , 50 ]. And the peaks at 1607 cm −1 and 1396 cm −1 correspond to the asymmetric stretching of NO 2 [ 50 ].…”

“…While the peak at 1633 cm −1 and 1631 cm −1 signifies C=C stretching vibrations of the hydrocarbon portion of biological double-bond molecules, the band at 1052 cm −1 and 1031 cm −1 may be attributed to C-O stretching [ 35 , 46 , 50 ]. And the peaks at 1607 cm −1 and 1396 cm −1 correspond to the asymmetric stretching of NO 2 [ 50 ]. Flavonoids, monoterpenes, iridoids, mites, and glycosides constitute the major compounds in the Oleaceae Hoffmans.…”