Fresh T. arjuna plant leaves were collected from Karaikudi (Tamil Nadu, India) and used to retrieve their extraction. First, the leaves were cleaned with tap water, followed by distilled water and then finely cut into small pieces. 10 g of finely cut leaves were added with 100 ml of double distilled water and boiled for 5 min. The obtained extraction was filtered using Whatman No. 1 filter paper and the filtrate was collected in 250 ml Erlenmeyer flask and stored at room temperature for further usage. Then, 1 ml of T. arjuna leaf extract was added to 100 ml of 1 mM HAuCl4 solution at room temperature and rapid reduction of Au NPs was clearly observed within next 15 min.