Introduction and Aim: Presently, research and development in nanomaterials is gaining hypersonic reach in various areas of applications.  Biological way of preparing such nanomaterials is acquiring noteworthiness in the view of affordability and environment-friendly approach. In this current work, gold nanoparticles(AuNPs) were prepared using leaves extract of Chloroxylon swietenia having anticancer behaviour with the focus to blend the therapeutic activity among the nanoparticles was studied by conjugating with 5 Fluorouracil (5-FU) to target breast cancer cells.   Materials and Methods: Chloroxylon swietenia leaf extract was prepared and chloroauric acid (HAuCl4) was added to synthesis AuNPs. As prepared AuNPs were characterized using UV-visible spectrophotometry, TEM and EDAX. The antioxidant tests were done by DPPH assay. Further, the AuNPs were conjugated with5-fluorouracil. The in vitro cytotoxicity of the synthesized gold nanoparticles and conjugated AuNPs were assessed by MTT assay against normal and A549 breast cancer cell lines and the efficacy was noted.   Results: Preparation of AuNPsthrough the leaf extract of C. swietenia was carried out in an effective way.The preliminary test for the confirmation of as synthesized NPs was done through spectroscopic analysis, resulting in a characteristic peak at 539nm. The TEM examination provided the information about size and the pattern of NPs. Cytotoxicity investigation of NPs with VERO cell lines confirmed its non-toxic nature towards the cells. Anticancer study with A549 breast cancer cell lines also proved the NPs with IC50 value at 25µl/ml.    Conclusion: The conjugated AuNPs with 5-FU revealed anticancer activity in A549 breast cancer cell line but correspondingly it is proved to be safe with standard VERO cell line. The findings stand with a strong point to expand the studies through the evolution of potential drug molecules to deal with the disease of interest.