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In this study, we reported millepachine (MIL), a novel chalcone compound for the first time isolated from Millettia pachycarpa Benth (Leguminosae), induced cell cycle arrest and apoptosis in human hepatocarcinoma cells in vitro and in vivo. In in vitro screening experiments, MIL showed strong antiproliferation activity in several human cancer cell lines, especially in HepG2 cells with an IC50 of 1.51 µM. Therefore, we chose HepG2 and SK-HEP-1 cells to study MIL's antitumor mechanism. Flow cytometry showed that MIL induced a G2/M arrest and apoptosis in a dose-dependent manner. Western blot demonstrated that MIL-induced G2/M arrest was correlated with the inhibition of cyclin-dependent kinase 1 activity, including a remarkable decrease in cell division cycle (cdc) 2 synthesis, the accumulation of phosphorylated-Thr14 and decrease of phosphorylation at Thr161 of cdc2. This effect was associated with the downregulation of cdc25C and upmodulation of checkpoint kinase 2 in response to DNA damage. MIL also activated caspase 9 and caspase 3, and significantly increased the ratio of Bax/Bcl-2 and stimulated the release of cytochrome c into cytosol, suggesting MIL induced apoptosis via mitochondrial apoptotic pathway. Associated with those effects, MIL also induced the generation of reactive oxygen species. In HepG2 tumor-bearing mice models, MIL remarkably and dose dependently inhibited tumor growth. Treatment of mice with MIL (20mg/kg intravenous [i.v.]) caused more than 65% tumor inhibition without cardiac damage compared with 47.57% tumor reduction by 5mg/kg i.v. doxorubicin with significant cardiac damage. These effects suggested that MIL and its easily modified structural derivative might be a potential lead compound for antitumor drug.

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Twenty-two compounds based on thiazolidine-2,4-dione moiety were synthesized and evaluated for the inhibitory potency on the production of nitric oxide (NO), inducible nitric oxide synthase (iNOS) activity, and the generation of prostaglandin E(2) (PEG(2)). (Z)-N-(3-chlorophenyl)-2-(4-((2,4-dioxothiazolidin-5-ylidene) methyl) phenoxy) acetamide (3I), superior to the commercial anti-inflammatory drug indomethacin, significantly inhibited iNOS activity (IC(50) = 8.66 μM), iNOS-mediated NO, and cyclooxygenase (COX)-2-derived PGE(2) production (IC(50) = 4.16 and 23.55 μM, respectively) on lipopolysaccharide (LPS)-induced RAW 264.7 cells. Docking study revealed that 3I was perfectly docking into the active site of murine iNOS and suppressed the expression of iNOS protein as evidenced by Western blot analysis. At the dose of 50 mg/kg, oral administration of 3I possessed protective properties in both carrageenan-induced paw edema and adjuvant-induced arthritis rat models.