Recently, the incidence of hepatocellular carcinoma has increased worldwide. Cembranoid-type diterpenes (CBDs) from tobacco exhibit good antimicrobial, antitumor, and neuroprotective activities. Therefore, in this study, we isolated CBDs from Nicotiana tabacum L. and evaluated their antitumor activity against hepatoma cell lines. Particularly, the anti-tumor activity of α-2,7,11-cyprotermine-4,6-diol (α-CBD) was investigated against HepG2, SMMC-7721, and HL-7702 cells. The MTT assay revealed that α-CBD reduced the formation of cell clones and inhibited the proliferation of hepatocellular carcinoma cells. Morphological observations showed that α-CBD altered cell morphology and membrane permeability before inducing apoptosis. To further explore the antitumor mechanism of α-CBD, flow cytometry and transcriptome analysis were performed using HepG2 cells. The results showed that the number of HepG2 cells increased from 10.4% to 29.8%, indicating that α-CBD inhibits the proliferation of hepatocellular carcinoma cells in the S phase. The gene expression analysis of HepG2 cells treated with α-CBD showed 3068 genes with altered expression, among which 1289 were upregulated and 1779 were downregulated. Apoptosis induced by these differentially expressed genes might be mediated by the p53-PUMA, PI3K-Akt, and IL-1-NF-κB-IAP pathways. Comprehensively, our study shows that α-CBD isolated from N. tabacum L. can be potentially used as a natural antitumor agent.

Four new μ 2 -oxo-bridged dinuclear aryltelluronic triorganotin esters [ArTe(μ-O)(OH)(OSnR 3 ) 2 ] 2 (Ar = n-propyl-Ph, R = Me: 1, R = Ph: 2; Ar = i-propyl-Ph, R = Me: 3, R = Ph: 4) were synthesized by reaction of μ 2 -oxo-bridged dinuclear aryltelluronic acids and the corresponding R 3 SnCl (R = Me, Ph) with potassium hydroxide in methanol. The complexes were characterized by X-ray crystallography, elemental analysis, FT-IR, and NMR ( 1 H, 13 C, 119 Sn) spectroscopy. The structural analysis indicates that these complexes are isostructural and crystallized as Sn 4 Te 2 molecules, in which the asymmetric four-membered Te 2 (μ 2 -O) 2 units are situated in the center. The geometry of tellurium is described as a distorted octahedron and each tin is described as a distorted tetrahedron. Complex 2 has a 2-D network structure connected by intermolecular C-H⋯π interactions. Complexes 1-4 were tested for in vitro cytotoxicity against human lung cancer cells (A549) and human hepatocellular carcinoma cells (HepG2).

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Six new arenetelluronic triorganotin esters, namely (R 3 Sn) 4 [ArTe(μ-O)(OH)O 2 )] 2 (Ar