Highly Concentrated Multifunctional Silver Nanoparticle Fabrication through Green Reduction of Silver Ions in Terms of Mechanics and Therapeutic Potentials.

Background: Green synthesis of silver nanoparticles (AgNPs) is limited to produce AgNPs with only relatively low concentrations, and is unsuitable for large-scale productions. The use of Myrtus communis (MC) leaf methanolic extract (rich in hydrolyzable tannins) has been recommended to resolve the issues related to the aggregation of nanoparticles at high concentrations of silver ions with added facet of antioxidant properties.

Methods: The produced highly concentrated MC-AgNPs were characterized by using imaging and spectroscopic methods. Subsequently, antioxidant, anticancer and antifungal activities of the nanoparticles were evaluated.

Results: The thermogravimetric analysis and energy dispersive spectroscopy quantitative results suggested that the nanoparticles are biphasic in nature (bio-molecule + Ag0) and layered in structure, suggesting the formation of nanoparticles through a different mechanism than those described in the literature. MC-AgNPs showed greater scavenging activity of nitric oxide and iron (II) chelating ability than the extract. It also showed good reducing power compared to the standard antioxidant. Remarkable anticancer activity of MC-AgNPs (IC50 = 5.99µg/mL) was found against HCT-116 (human colon carcinoma) cell lines after 24h exposure with a therapeutic index value 2-fold higher than the therapeutic index of standard doxorubicin. Furthermore, distinct antifungal activity (MIC = 4µg/mL) was found against Candida krusei.

Conclusion: The current method outperforms the existing methods because it produces a large amount of multifunctional nanoscale hybrid materials more efficiently using natural sources; thus, it may be used for diverse biomedical applications.