Aims: Formulation and evaluation of quercetin-loaded nanoparticles Background: Nowadays, polymeric nanoparticles are one of the most chosen drug delivery systems for the treatment of life-threatening diseases such as cancer. Drug loading, drug entrapment, and drug release have been the challenges in nanoformulations till now. Various researchers are working to improve these limitations. Objective: Formulation of quercetin-loaded starch nanoparticles .Evaluation of drug loading, entrapment, size release, and activity of prepared starch nanoparticles Methods: In the present study, starch was isolated from a novel source, i.e., unripe banana fruit. Banana starch contains amylose and amylopectin in a certain ratio. Quercetin-loaded banana starch nanoparticles were prepared using the nano-precipitation method. Drug loading and drug entrapment were determined by different methods. Results: The enhanced water absorption capacity of prepared nanoparticles proved the breaking of intra-molecular bonding of amylopectin. In-vitro drug release of quercetin was found to be sustained for up to 12 hours from prepared nanoparticles. SEM was used to determine the particle size and morphology of prepared particles, which were found to be 67.67-133.27 and spherical, respectively. The antioxidant activity of prepared nanoparticles was evaluated by the DPPH scavenging model. The MTT assay for cytotoxicity studies was done using H661 lung cancer cell lines. Conclusion: In this research work, banana as a new source of starch was used to prepare quercetin nanoparticles by nano-precipitation method. The various factors of starch that affect the properties of nanoparticles such as water/oil absorption capacity, drug entrapment/loading, and drug release profile were studied. This study also revealed the effect of starch on particle morphology and size. The yield of prepared nanoparticles was lower than expected but particle size and shape were satisfactory. Prepared nanoparticles were evaluated for their antioxidant and cytotoxic potential. Finally, researchers felt the ratio of amylase and amylopectin were considerable factors in the selection of any starch for the formulation of any drug delivery system. This ratio affects the precipitation of nanoparticles, their properties such as oil/water absorption, drug entrapment, and loading as well as the drug release profile of the formulation.