Green Synthesis and Characterization of Silver Nanoparticles Using Traditional Medicinal Herb Phyllanthus Maderaspatensis for their Antibacterial and Anti-biofilm Activities

Abstract

The misuse of antibiotics has led to the rise of multidrug-resistant (MDR) pathogens, posing a significant threat to global health. The shortcoming of new antibiotics with novel mode of action augments this challenge. Nanoparticles, particularly synthesized through green synthesis methods, have emerged as promising agents to combat the growing issue of MDR. The current study focuses on the green synthesis of silver nanoparticles (AgNPs) using seed extract from the traditional medicinal herbaceous plant Phyllanthus maderaspatensis (PM). AgNPs were synthesized by mixing the PM seed extract (PMSE) with 3 mM silver nitrate at 80 °C for 15 min, followed by precipitation using acetone and drying at 70 °C. Characterization of the derived AgNPs with UV spectroscopy resulted absorption maximum at 430 nm. FTIR analysis revealed the capping of functional moieties such as alcohol, amine, aldehyde, alkene and halo to their surfaces. SEM and TEM analysis disclosed the spherical and quasi-spherical shaped nanoparticles, with smooth surface and notable lattice fringes appearance. The size of AgNPs ranges from ~ 5 nm to ~ 78 nm in diameter. The synthesised nanoparticles happen to be highly stable as deduced via mean zeta potential of -37.9 mV. XRD and energy dispersive X-ray spectrum of the synthesized AgNPs conforms the presence of silver in the synthesised nanoparticles. The antimicrobial potential of the synthesized AgNPs against different bacterial strains provides minimum inhibitory concentration values as low as 150 to 225 µg/mL. Additionally, the AgNPs also exhibited outstanding anti-biofilm capabilities. Crystal violet uptake assay and light microscopy studies indicates that membrane disruption contributes to their bactericidal effect. Altogether, the utilization of PMSE as a reducing agent holds promise as a cost-effective, scalable, and eco-friendly alternative to traditional AgNP synthesis methods. This PMSE derived AgNPs demonstrate strong potential for broad applications namely in agriculture for management of PM seeds and across medicine such as development of anti-bacterial coating or as an active ingredient in wound dressing.