The aim of this study was to synthesize the alginate nanogel encapsulating Artemisia ciniformis extract and to evaluate its apoptotic effects on AGS gastric cancer cells. Characterization of the synthesized nanogel was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Dynamic light scattering method (DLS), and Zeta potential. The cytotoxic effects and apoptosis induction of A. ciniformis extract, nanogel encapsulating A. ciniformis extract and alginate nanogel alone were evaluated in the AGS cell line using MTT assay, Annexin-FITC, DAPI staining, cell cycle analysis, and real-time PCR for 24, 48 and 72 h. Anti-proliferative activity and apoptosis induction were observed in the cells treated with alginate nanogel encapsulating A. ciniformis extract and free extract. The alginate nanogel encapsulating A. ciniformis extract had greater potential for the induction of apoptosis than free extract. Flowcytometric results of the cell cycle showed that synthesized nanogel encapsulating A. ciniformis extract could inhibit cell proliferation and arrest the cell cycle at the G0/G1 phase. Induction of apoptosis occurred in a time-, and dose-dependent manner. Expression levels of pro-apoptotic genes were up-regulated. Down-regulation of anti-apoptotic and metastatic genes were detected. It can be concluded that nanogel encapsulating A. ciniformis extract would be a potent anticancer agent against AGS gastric cancer cells. (c) 2020 Elsevier B.V. All rights reserved.