Green synthesis of silver nanoparticles using Azadirachta indica (Neem) fruit pulp extract and their antioxidant, antibacterial, and anticancer activity

Abstract

In this research, silver nanoparticles (AgNPs) were synthesized using Azadirachta indica (Neem) fruit pulp extract as a natural reducing agent. The synthesized AgNPs were characterized by the TEM, AFM, XRD, DLS, FTIR, and UV–visible spectral analysis. Visual confirmation of AgNP synthesis was indicated by the appearance of a reddish-brown color, further supported by a UV–visible SPR band at approximately 453 nm. FTIR analysis supported the formation and stabilization of the nanoparticles, attributed to the phytochemicals present in the flower extract. The AgNPs were characterized by XRD analysis that confirmed the FCC crystalline nature of the AgNPs with an average crystalline size of 20.8 nm. EDX confirmed the presence of elemental silver. HRTEM images showed that the AgNPs are nearly spherical with an average size of 31.5 nm. The high negative potential value of AgNPs (−36.7 mV) was evident from DLS studies. AFM data revealed that the particles were agglomerated and spherical in shape, with less than 40 nm. The AgNPs also exhibited good antioxidant activities against DPPH radical with 66.72 % radical scavenging ability. The biosynthesized AgNPs demonstrated notable anticancer activity against burst cancer cell lines (77.28 µg/mL in the MTT assay) and demonstrated good antibacterial activities against gram-negative bacteria and gram-positive bacteria with a Zone of inhibition ranging from 8 to 16 mm. This study demonstrates the synthesis of AgNPs and their promising in biomedical applications, and the benefits of using plant extracts to prepare green nanoparticles.