Antimicrobial Potential of Andrographis paniculata Conjugated Gold Nanoparticle

Background: Herbal extracts have been traditionally used as antibacterial agents, and different strategies have been proposed to enhance their antimicrobial activities. This research aimed to assess the antimicrobial potential of Andrographis paniculata conjugated gold nanoparticle (GNP) compounds against Escherichia coli and Bacillus subtilis.Methods: Herbal extract was conjugated with GNP through electrostatic interaction, and characterization was carried out by Fourier-transmission infrared spectroscopy, screening electron microscopy, and transmission electron microscopy and supported by energy-dispersive X-ray spectroscopy. Antibacterial activity of the herbal extract and GNP conjugation was evaluated by disc diffusion assay.Results: Chemical and morphological characterizations of the GNP and herbal extract conjugate revealed intactness of the GNP. In disc diffusion assay, the inhibition zone formed by these compounds was measured for both microorganisms, and they were in the range of 0.6-0.9 cm for the herbal extract. When the herbal extract conjugated with GNP, the zone was between 0.8 and 1.1 cm.Conclusion: This study demonstrated the potentiality of GNP to carry the antibacterial compounds from the herbal extract.