Couroupita guianensis is commonly known as cannonball tree, belonging to the family Lecythidaceae. This tree has enormous medicinal values since most of its parts are used as medicines traditionally. In this work, two major aspects were studied. Firstly, the phytochemical screening and biological activities of various extracts of leaf, flower and fruit are prepared and studied. Secondly, silver nanoparticles were synthesized from these parts, characterized instrumentally and checked for its antibacterial activity. This study reveals that except the aqueous extracts, all other extracts have good antioxidant and antibacterial activity hence stating the presence of bioactive compounds. Flower mediated nanoparticles showed better results than others which may be due to the presence of certain phytochemical compounds responsible for the reduction and capping of silver nanoparticles. These results showed the potential of Couroupita guianensis and further investigation to isolate such pharmacologically active compounds that can be used in the production of novel drugs for various diseases would be promising.