Pentagamavunon-1 (PGV-1), a potential chemopreventive agent with a strong cytotoxic effect, modulates prometaphase arrest. Improvement to get higher effectiveness of PGV-1 is a new challenge. A previous study reported that the natural compound, galangin, has antiproliferative activity against cancer cells with a lower cytotoxicity effect. This study aims to develop a combinatorial treatment of PGV-1 and galangin as an anticancer agent with higher effectiveness than a single agent. In this study, 4T1, a TNBC model cell, was treated with a combination of PGV-1 and galangin. As a result, PGV-1 and galangin showed a cytotoxic effect with IC50 values of 8 and 120 µM, respectively. Combining those chemicals has a synergistic impact, as shown by the combination index (CI) value of 1. Staining with the May Grunwald-Giemsa reagent indicated mitotic catastrophe evidence, characterized by micronuclear and multinucleated morphology. Moreover, the senescence percentage was higher than the single treatment. Furthermore, bioinformatics investigations showed that PGV-1 and galangin target CDK1, PLK1, and AURKB, overexpression proteins in TNBC that are essential in regulating cell cycle arrest. In conclusion, the combination of PGV-1 and galangin exhibit a synergistic effect and potential to be a chemotherapeutic drug by the mechanism of mitotic catastrophe and senescence induction.