Bi-bicyclic and bi-tricyclic compounds from Dendrobium thyrsiflorum

• Published in: Phytochemistry (Oxford) 2005-05, Vol.66 (10), p.1113-1120
• Main Authors: Zhang, Guang-Nong, Zhong, Ling-Yan, Annie Bligh, S.W., Guo, Ying-Li, Zhang, Chao-Feng, Zhang, Mian, Wang, Zheng-Tao, Xu, Luo-Shan
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; anticarcinogenic activity; Antineoplastic Agents, Phytogenic - chemistry; Antineoplastic Agents, Phytogenic - pharmacology; Applied ecology; benzofuran; Biological and medical sciences; Cell Line, Tumor; Chemical constitution; chemical structure; coumarin; cultured cells; Cytotoxic activity; cytotoxicity; Dendrobium; Dendrobium - chemistry; Dendrobium thyrsiflorum; Denthyrsin; denthyrsinin; Denthyrsinol; Denthyrsinone; dimethoxybenzofuran; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Fundamental and applied biological sciences. Psychology; Humans; Hydrocarbons, Cyclic - chemistry; Hydrocarbons, Cyclic - pharmacology; Molecular Structure; Orchidaceae; phenanthraquinone; phenanthrene; phytochemicals; plant extracts; Plant physiology and development; Plant Stems - chemistry; spectral analysis; stereochemistry; trimethoxyphenanthrene
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2005.04.001

Coumarin–benzofuran, dimeric phenanthrene and phenanthrene–phenanthraquinone derivatives, along with seven known ones, were isolated from Dendrobium thyrsiflorum (Orchidaceae). Four of the compounds showed significant cytotoxic activities against Hela, K-562 and MCF-7 cell lines. One bi-bicyclic and two bi-tricyclic derivatives of coumarin–benzofuran, phenanthrene–phenanthrene and phenanthrene–phenanthraquinone, along with seven known compounds, were isolated from stems of Dendrobium thyrsiflorum Rchb.f. (Orchidaceae). On the basis of chemical, NMR ( 1H, 13C, HMQC, HMBC and NOESY) and mass spectrometry data, their structures were elucidated as denthyrsin [3-(5′,6′-dimethoxybenzofuran-2′-yl)-6,7-dimethoxy-2H-chromen-2-one; 1], denthyrsinol (4,5′-dimethoxy-[1,1′]biphenanthrenyl-2,5,4′,7′-tetraol; 2), and denthyrsinone (7,4′,7′-trihydroxy-2,2′,8′-trimethoxy-[5,1′]biphenanthrenyl-1,4-dione; 3). Compounds 1– 3 and denthyrsinin (1,5,7-trimethoxyphenanthrene-2,6-diol; 4) showed significant cytotoxic activities against Hela (13.5, 9.3, 9.9 and 2.7 μM, respectively), K-562 (0.45, 1.6, 6.0 and 2.3 μM, respectively) and MCF-7 (18.1, not tested, 3.5 and 4.8 μM, respectively) cell lines.