¹Rajiv Gandhi Institute of Pharmacy, Faculty of Pharmaceutical Science & Technology, AKS University, Satna (MP)- India DOI : 10.29228/jrp.2022.00 Tinospora cordifolia extracts are extensively used in various herbal preparations for the treatment of different ailments for its anti-periodic, anti-spasmodic, anti-microbial, anti-osteoporotic, anti-inflammatory, anti-arthritic, anti-allergic, and anti-diabetic properties. In the present investigation the aqueous extract of leaf of Tinospora cordifolia was used as reducing agent for the synthesis of Selenium nanoparticles. The total phenolic content of the extract was determined by derivatization with Folin-ciocalteu reagent and measuring the absorbance in UV-visible spectrophotometer at 765 nm. The SeNPs prepared by reduction of sodium selenite by the extract were assessed in terms of FTIR, UV absorption, size, and form and antidepressant action using forced swim test in mice. The extract solution was dark green in color and contained 1.3 ± 0.003 GAE/mg of phenolics. Se NP was produced rapidly with ascorbic acid as well as Tinospora cordifolia extract. The formation of Se NP is indicated by an absorbance at 226.0 nm in the ultraviolet spectrum. The FTIR spectrum revealed the stretching and bending vibrations of O-H, C-H, C-C, N-O, C-N, and other groups due to the presence of phytoconstituent composition. It was discovered that the concentration of the extract, or reducing agent, had an impact on the size of the Se NP nanoparticles, which ranged in size from 46 to 137 nm. The SEM images showed smooth particles with a spherical structure. The Se NPs synthesized using Tinospora cordifolia leaf extract exhibited antidepressant action in a concentration dependent manner. The lowest immobility time was depicted by Se NPE4 (1.115 ± 0.0213 min).. Keywords : Selenium nanoparticles; Tinospora cordifolia; Biogenic reduction; green synthesis; sodium selenite