Investigation of the biological activity of silver nanoparticles biosynthesized from Echinops ritro L

The biosynthesis of silver nanoparticles (AgNPs) is the subject of this investigation using the ethanolic extract of Echinops ritro L., a medicinal plant from the Asteraceae family, and evaluates their antimicrobial properties. A combination of spectroscopic methods was used to characterise the biosynthesised AgNPs. The UV-visible spectrum showed a characteristic absorption band at 415 nm, confirming AgNPs formation investigation revealed several functional groups that contribute to the stabilisation and reduction of AgNPs. XRD confirmed the crystalline nature of the nanoparticles with an average size of 23.36 nm. The antimicrobial activity of the synthesized AgNPs was assessed against five bacterial strains (Escherichia coli, Enterococcus faecalis, Proteus mirabilis, Enterococcus hirae, and Bacillus cereus) and one fungal species (Candida albicans) using the disc diffusion method. The AgNPs exhibited significant antibacterial activity, with inhibition zones ranging from 5 to 33 mm, depending on the concentration and bacterial strain tested. The E. coli bacteria showed the strongest antibacterial activity, with an inhibitory zone measuring 33±12.5 mm at a concentration of 100 μg/mL. The AgNPs also demonstrated antifungal activity against C. albicans, with a maximum inhibition zone of 21± mm at 100 μg/mL. This research highlights the potential of Echinops ritro L. extract for the green synthesis of AgNPs with promising antimicrobial properties, offering a sustainable approach for developing new antimicrobial agents.