Phytochemical study of Chiliadenus montanus aerial parts afforded six compounds; Intermedeol (1), 5α-hydroperoxy-β-eudesmol (2), 5,7-dihydroxy-3,3’,4’-trimethoxyflavone (3), 5,7,4’-trihydroxy-3,6,3’-trimethoxyflavone (jaceidin) (4), eudesm-11,13-ene-1β,4β,7α-triol (5) and 1β,4β,7β,11-tetrahydroxyeudesmane (6). These compounds were identified based on their NMR spectral data. The isolated compounds were tested for their cytotoxicity against liver cancer cell line (HepG2) and breast cancer cell line (MCF-7). Jaceidin flavonoid (4) exhibited the highest cytotoxic effect in vitro. Therefore, both of jaceidin and C. montanus extract were evaluated for their in vivo anti-tumor activity against Ehrlich’s ascites carcinoma (EAC). Compared to control group, jaceidin and C. montanus extract decreased the tumor weight, improved the histological picture of tumor cells, lowered the levels of VEGF and ameliorate the oxidative stress. Molecular docking and in silico studies suggested that jaceidin was a selective inhibitor of VEGF-mediated angiogenesis with excellent membrane permeability and oral bioavailability.