ABSTRACT: Quinazoline derivatives display multiple pharmacological activities and target various biological receptors. Based on the skeleton of quinazoline core, we designed and synthesized three new quinazoline-phenyl chlormethine conjugates (I-III) bearing a Schiff base (C = N) linker, and investigated their anti-tumor effects on HepG2-xenografted tumor and human cancer cell line HepG2. Among these compounds, compound II showed better inhibitory effect against HepG2 cells. In the present study, TUNEL staining, western blot, molecular docking, and siRNA were used to investigate the inhibitory mechanism of compound II towards hepatoma. Compound II inhibited HepG2-xenografted tumor growth in nude mice. Moreover, Compound II not only up-regulated Bax/Bcl-2 ratio and active-caspase 3 level, but also down-regulated Sirt1 expression and its activity, as well as PGC-1? expression. Furthermore, compound II also significantly suppressed the promotion of HepG2 cell proliferation, as evidenced by MTT assay and lactate dehydrogenase (LDH) release assay. Of note, the cytotoxicity of Compound II on HepG2 cells mainly via regulating Sirt1/caspase 3 signaling pathway, consisting with the results in vivo. Intriguingly, z-DEVD-FMK, a caspase 3 inhibitor, almost abolished the inhibitory effects of compound II. Of note, knockdown of caspase 3 by siRNA significantly reversed the inhibitory effect of compound II on HepG2. Interestingly, compound II directly bonded to Sirt1, indicating that Sirt1 might be a promising therapeutic target of compound II. In summary, our findings reveal that compound II, a new synthetical phenyl chlormethine-quinazoline derivative, contributes to the apoptosis of HepG2 cells both in vivo and in vitro through mediating Sirt1/caspase 3 singling pathway. These findings demonstrate that compound II may be a new potent agent against hepatocellular carcinoma.