Green synthesis of gold nanoparticles using Jatropha integerrima Jacq. flower extract and their antibacterial activity

With the rise of antibiotic resistance, there is an increasing interest in discovering novel antimicrobial agents. Antibiotics could be replaced with metal-based nanoparticles that have long-lasting antibacterial properties. This study aimed to synthesize gold nanoparticles (AuNPs) and test their antibacterial effectiveness against a variety of human pathogens. The AuNPs were characterized using UV, FT-IR, XRD, and TEM with EDX. By using the well diffusion and microdilution techniques, the impact of synthesized AuNPs was tested against B. subtilis, S. aureus, E. coli, and K. pneumoniae. The AuNPs were synthesized from Jatropha integerrima Jacq. flower extract. UV–vis spectrum showed a high peak at 547 nm; FT-IR revealed phenolic compounds in the plant extract were responsible for AuNP formation. XRD and SAED confirmed the crystalline nature while TEM revealed the shape to be spherical and DLS revealed the size to be 38.8 nm with the stability of −0.3 mV. The AuNPs exhibit maximal and minimal antibacterial activity towards E. coli and B. subtilis. The MIC of AuNPs against B. subtilis, S. aureus, E. coli, and K. pneumoniae were found to be 5.0, 10, 2.5, and 2.5 μg/mL, respectively. Thus, synthesized nanoparticles might be a good alternative to develop an antibacterial agent against the selected human pathogens.