Abstract: Trihydroxybenzoic acid show the anti-tumor potency from many previous investigations, but the research for the inhibitory effect and mechanism on SMMC-7721 cells has not been regarded so far. MTT assay was used to evaluate the anti-proliferation effect of trihydroxybenzoic acid on SMMC-7721 cells and human PBMC. ROS production, apoptotic cells and the mitochondrial membrane potential were detected by flow cytometry. The activities of Caspase-3,9 were measured by colorimetric method. The results show that trihydroxybenzoic acid significantly inhibit the proliferation of SMMC-7721 cells in dose and time-dependent pathways. Compared with control group, trihydroxybenzoic acid caused the increase of ROS levels and a concomitant dissipation of the mitochondrial membrane potential, activities caspase-9 and caspase-3, triggering apoptosis of SMMC-7721 cells. Mitochondrial-dependent pathways could involved in trihydroxybenzoic acid induced SMM-7721 cells apoptosis.

Key words: Trihydroxybenzoic acid, Human hepatocarcinoma SMMC-7721 cells, Apoptosis, Mitochondrial membrane potential