ABSTRACT
The development of antibacterial agents is increasingly gaining much attention due to the expansion activity ofmulti-drug resistant bacteria in causing many diseases. Metallic nanoparticles especially gold nanoparticles in thefield of nanotechnology is one of the new and significant materials to be developed as antibacterial agents. Goldnanoparticles have been successfully synthesized using Uncaria gambir Roxb. leaf extract as a bioreducing agent andtriethanolamine as a capping agent, through reduction of Au+3 by flavonoid compound in the leaf extract. The effect oftriethanolamine and hydrogen tetrachloroaurate (III) acid concentration on the stability and size of nanoparticles wasstudied. The presence of triethanolamine 1% as a capping agent successfully maintained the stability of colloidal goldnanoparticles with a concentration of hydrogen tetrachloroaurate (III) acid at 100 ppm. X-Ray Diffraction analysisshowed peak patterns corresponding to the metallic gold standard with a crystallite size of 32.52 nm. TransmissionElectron Microscope analysis showed that particles were spherical, hexagonal, and triangular, where the smallestparticle size was 7 nm. Synthesized gold nanoparticles showed great antibacterial activity against E. coli and S. aureus.The stability and antibacterial activity of synthesized gold nanoparticles showed good potential to be developed inbiomedical applications