Gold nanoparticles have many advantages in their use, especially in delivering an active substance because of their properties of having nano sized particles. The purpose of this research is to make gold nanoparticle from Sidaguri plant extract. Sidaguri has fenolic compounds that can reduce Au3+ into a more stable Auo form, this method known as Green Synthesis. The making of gold nanoparticles from plant extracts was then characterized to prove the gold nanoparticles had been formed using Uv-Vis spectrophotometry and based on color changes in the solution. The gold nanoparticle solution was formulated into a serum and was evaluated for its stability by 12-day cycling test consisting of 6 cycles. The results showed that the gold nanoparticle solution showed a UV absorption at a wavelength of 530.8 nm which proves that gold nanoparticles have been formed and solutions that show change of color from yellow to blackish purple. After the serum preparation was formulated and can be known that it was stable after a 12-day cycling test evaluation (6 cycles) was carried out with the parameter of organoleptic, spreadability, viscosity, rheology and pH. This research showed that serum containing gold nanoparticles have been successfully prepared with green synthesis method and was stable.

Keyword                     : Gold Nanoparticle, Sidaguri (Sida rhombifolia L.), Green synthesis, Serum, Serum Stability