Nanotechnology is a practical and exquisite method for enhancing the bioavailability of insect medicines. The present work deals with nano-encapsulation of freeze-dried Polyrhachis sp. (Pol) to increase its aqueous solubility and bioactivity. In the current study, Polyrhachis sp. was encapsulated into carbonate calcium (CaCO 3 ) through a one-step co-precipitation method to produce CaCO 3 @Pol nanoparticles (NPs). It was characterized accordingly by FTIR, FESEM, DLS, and zeta potential analysis methods. Null CaCO 3 and CaCO 3 @Pol particle sizes were observed in the nano range, and most of the nanoparticles had spherical shapes. The cytotoxicity evaluation of neat Pol and CaCO 3 @Pol was performed in vitro on human breast cancer cells (MCF7) and human gastric cancer cells (AGS) through an MTT assay. Morphological alternation studies disclosed that CaCO 3 @Pol-treated cells had undergone apoptosis since shrinkage and apoptotic bodies were observed. The half-maximal inhibitory and 50% lethal dose of neat Pol and CaCO 3 @Pol were calculated. Besides, the RT-PCR technique analyzed the status of apoptosis genes such as caspase-3, caspase-8, caspase-9, Bcl-2, and Bax expressions. The molecular mechanisms provoked apoptosis through modulating pro (caspase-8, caspase-9, Bax) and anti-apoptotic (Bcl-2) mediator genes expression in AGS cells. The findings conveyed that the CaCO 3 @Pol is a promising biomaterial for future biomedical applications.