Biological synthesis of silver nanoparticles and evaluation of antibacterial and antifungal properties of silver and copper nanoparticles

There is increasing attention being paid to metallic nanoparticles because of their intensive applications in different areas of science such as medicine, chemistry, agriculture, and biotechnology. In addition, there has been growing interest in using environmentally friendly methods of synthesizing nanoparticles without making or using substances risky to the environment and human health. Biological methods for the synthesis of nanoparticles have been considered as possible ecofriendly alternatives to chemical synthesis. In the present study, biosynthesis and characterization of silver nanoparticles (SNPs) using marshmallow flower (Althaea officinalis L.), thyme (Thymus vulgaris L.), and pennyroyal (Mentha pulegium L.) leaf extracts is reported for the first time. Copper nanoparticles (CuNPs) were formed by reduction of CuCl2 with L-ascorbic acid. The antibacterial and antifungal effects of SNPs and CuNPs in comparison with silver nitrate (AgNO3) and copper chloride (CuCl2) (respective nanoparticle constrictive salts) and synthetic antibiotics and fungicides were studied. Fungi (A. flavus and P. chrysogenum) and bacteria (E. coli and S. aureus) showed clear hypersensitivity to silver and copper nanoparticles, and the effects of SNPs were more notable than those of CuNPs. Data analysis showed that copper chloride and silver nitrate had a lower inhibitory effect in their nanoparticles, especially against the tested fungi.