Green synthesis of silver nanoparticles from Fraxinus angustifolia Vahl. Extract: Characterization and assessment of their biological activities

Nanoparticle synthesis for biological devices is one of the most promising research fields invading the world. This work aimed to synthesize ecofriendly silver nanoparticles (AgNPs) with enhanced biological activities. A green method was adopted to synthesize, for the first time, AgNPs from Fraxinus angustifolia extracts. The AgNPs structural and morphological properties were characterized. Their antioxidant, antimicrobial and antidiabetic effects were investigated. Their cytotoxic and genotoxic effects were explored using the novel method of acetocarmine dye. Results confirmed the formation of stable, mono-dispersed and spheric nanoparticles with a Face-Centered Cubic crystalline structure, sized from 30.12 to 49.62 nm. The AgNPs showed high antioxidant activities (DPPH, β -carotene bleaching and total antioxidant activities). They significantly inhibited the growth of the multi-drug resistant pathogens Escherchia coli and Candida tropicalis. However, they showed moderate inhibitory activity against biofilm production of E. coli and C. tropicalis, with 65 and 63% inhibition, respectively. F. angustifolia AgNPs exhibited interesting antidiabetic activity, exceeding that of the acarbose. Interestingly, the acetocarmine stanning was approved as an exploration technique for the screening of cytotoxic and genotoxic effects. Allium cepa epidermis tissues treated by the AgNPs presented a visible morphological change in the cell membrane and the disruption of the nuclear envelope. The obtained results highlighted the versatile biological potential of F. angustifolia AgNPs allowing their use as green nanomaterials in food preservation, pharmaceutical formulation and in food quality prospecting. This work also affords a new method for screening possible cytotoxicity and genotoxicity of nanomaterials in agri-food applications.