The facile synthesis of ultra stable gold nanoparticles (GNPSs) is demonstrated using fruit peel extract of Momordica charantia. The best parameters for the synthesis of gold nanoparticles were pH10, high temperature (1000C) and 100 ppm aurochlorate salt. The results were verified using UV-Vis spectroscopy, XRD and Transmission electron microscopy. The GNPSs were monodisperse and found to be 10-100 nm in size. The stability of the GNPs synthesised using biological protocols was found to be extremely high than the chemically synthesised GNPs when tested using 5M NaCl solution. The Nitrate reductase activity was found to be 0.1667 mmole/min/gram of plant tissue which got reduced to 0.0132 mmole/min/gram in the solution after the formation of gold nanoparticles. The protein content got depleted after the formation of GNPSs in the solution from 214.12 mg/ml to 64.42 mg/ml.
