Many nutraceuticals are highly potent, nontoxic, bioactive agents present in dietary vegetables, fruits and spices. They exhibit immune‐modulatory, antioxidant and anticancer activity. The major disadvantage of nutraceuticals is their low aqueous solubility and hence poor bioavailability hindering their therapeutic applications. In the present work, we herein report preparation of nanoparticles of bioactive nutraceuticals such as curcumin (1), quercetin (2), anthraquinone (3), xanthone (4), flavone (5) and vanillin (6) with a view to improve their aqueous‐phase solubility and evaluate their anticancer, antiangiogenic and antioxidant activities. The nanoparticles were prepared by controlled flow rate reprecipitation technique and characterized by spectral and microscopic techniques. Most of the nanoparticles displayed higher in‐vitro anticancer, antioxidant and in‐ovo antiangiogenic activities as compared to the corresponding bulk compounds. The biological activities of nutraceuticals are marked increased by particle size reduction to the nanoscale.