The design, synthesis, characterization and application of biologically synthesized nanomaterials have become an important branch of nanotechnology. In this paper, we report the extracellular synthesis of gold nanoparticles using Barbated Skullcup (BS) herb (a dried whole plant of Scutellaria barbata D. Don) as the reducing agent. After exposing the gold ions to BS herb extract, rapid reduction of gold ions is observed leading to the formation of gold nanoparticles in solution. UV-vis spectrum of the aqueous medium containing gold nanoparticles showed a peak at around 540 nm. Transmission electron microscopy (TEM) micrograph analysis of the gold nanoparticles indicated that they were well-dispersed and ranged in size 5-30 nm. When the gold nanoparticles were modified on the glassy carbon electrode (GCE), it could enhance electronic transmission rate between the electrode and the p-nitrophenol.