SYNTHESIS OF GOLD NANOPARTICLES FROM LEAF EXTRACT OF Vitex grandifolia AND EVALUATION OF ITS ANTIBACTERIAL ACTIVITY AGAINST MULTI DRUG RESISTANT BACTERIA

The alarming prevalence of multidrug-resistant (MDR) bacteria threatens global public health. Current research has investigated the use of gold nanoparticles (AuNPs) as a potential solution. As a result, this study tends to establish that gold nanoparticles (AuNPs) synthesised from Vitex grandifolia leaf extract can be effective against these pathogens. Sunlight-driven synthesis was used for the gold nanoparticle synthesis. The application of techniques such as ultraviolet-visible-spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD,) and Transmission electron microscopy (TEM) were used for the detailed characterisation of the synthesised nanoparticles. The antimicrobial efficacy of the AuNPs against these multidrug-resistant pathogens was accessed using the agar well diffusion method at various concentrations that range between 10µg/ml -100µg/ml. The obtained UV-Vis result indicated that the absorbance peak of the synthesised nanoparticle was between 400nm and 600nm of visible light region, with a band gap at 3.5eV. Also, the FTIR results showed peaks that ranged between 470.96𝑐𝑚−1 and 3433.17𝑐, 𝑚−1 which are functional groups such as alkenyl C=C stretch, OH stretches, and polysulfides. To validate its antibacterial activity, AuNPs exhibited a zone of inhibition that ranges between 7mm and 13mm against various pathogens such as Pseudomonas aeruginosa, Salmonella typhi, Streptococcus pyogenes and Klebsiella pneumoniae at different concentrations. Thus, this study offers a rapid and cost-effective method for synthesising AuNPs using Vitex grandifolia. This indicates positive potential in tackling multidrug-resistant pathogens, reducing the milestone in this research study.