Eco-friendly synthesis of silver nanoparticles using leaf extract of Flemingia wightiana: spectral characterization, antioxidant and anticancer activity studies

In the present investigation, we report simple, robust and eco-friendly synthesis of silver nanoparticles (AgNPs) using leaf extract of Flemingia wightiana. The leaf extract of F. wightiana acts as reducing agent which reduces the silver ions into FW-AgNPs, as well as stabilizing agent by capping around them. Biosynthesized FW-AgNPs were characterized by different spectroscopic techniques. UV–Vis spectrum showed the characteristic SPR peak between 380 and 460 nm. EDX analysis revealed the presence of metallic silver at 3 keV. XRD analysis clearly revealed that FW-AgNPs are crystalline in nature with FCC structure. TEM analysis depicted the spherical morphology with 20–40 nm in size. DLS analysis showed that average hydrodynamic size and PDI value of FW-AgNPs were found to be 47.6 nm and 4.5 respectively. Biosynthesized FW-AgNPs showed high negative zeta potential value of − 25.3 mV. FTIR analysis revealed the participation of polyphenols and proteins in the bioreduction and stabilization of FW-AgNPs. FW-AgNPs showed strong DPPH and H2O2 scavenging activity with IC50 values of 71.96 and 80.59 µg/mL respectively. Further FW-AgNPs also showed effective cytotoxicity against cancer cells including SKOV3 and COLO205 with maximum inhibition of 83.2% and 75.9% respectively.