Breast cancer is the leading cause of cancer mortality in women. In this study, liriodenine and lysicamine from Goniothalamus elegans Ast. were investigated for their anti-breast cancer activity based on their molecular interactions with three proteins related to breast cancer. Liriodenine had predicted binding affinities for BRCA1, BRCA2, and estrogen receptor alpha of -6.2, -7.9, and -8.3 kcal/mol, respectively. Lysicamine had predicted binding affinities of -5.8, -7.2, and 7.6 kcal/mol. To evaluate the biological activity of liriodenine and lysicamine, we studied their in vitro cytotoxic effects on MCF-7 cells. These alkaloids showed significant inhibitory effects with IC50 values of 33.31 and 70.03 mu M. These results suggest that Goniothalamus elegans could be a promising medical plant for breast cancer treatment. Further studies are needed to understand the molecular mechanisms and improve the toxicity of liriodenine and lysicamine for clinical use.