title: Labdane diterpenoids and highly methoxylated bibenzyls from the liverwort Frullania inouei.
abstract: Four undescribed labdane diterpenoids, 1,2-dehydro-3,7-dioxo-manoyl oxide (1), 1,2-dehydro-7 beta-hydroxy-3-oxo-manoyl oxide (2), 3,7-dioxo-manoyl oxide (3), and 3beta-hydroxy-7-oxo-manoyl oxide (4) together with three known diterpenoids (5-7) and four highly methoxylated bibenzyls (8-11) were isolated from the liverwort Frullania inouei. The absolute structures of 1-4 were established by combined analysis of NMR data, CD data coupled with TDDFT CD calculations, and single-crystal X-ray diffraction measurement. Cytotoxicity tests to human tumor KB, KB/VCR, K562 or K562/A02 cells showed bibenzyls 8-11 inhibited cell proliferation with ID(50) values ranging from 11.3 to 49.6 microM and overcame the multidrug resistance (MDR) with the reversal fold (RF) values ranging from 3.19 to 10.91 (5 microM) for vincristine-resistant KB/VCR and RF values from 4.40 to 8.26 (5 microM) for adriamycin-resistant K562/A02 cells, respectively. However, none of the diterpenoids were found to be active (ID(50)>50 microM).
authors.affiliation: Department of Natural Products Chemistry, School of Pharmaceutical Sciences, Shandong University, No. 44 West Wenhua Road, Jinan 250012, People's Republic of China.
authors.forename: Dong-Xiao
authors.initials: DX
authors.lastname: Guo
authors.forename: Feng
authors.initials: F
authors.lastname: Xiang
authors.forename: Xiao-Ning
authors.initials: XN
authors.lastname: Wang
authors.forename: Hui-Qing
authors.initials: HQ
authors.lastname: Yuan
authors.forename: Guang-Min
authors.initials: GM
authors.lastname: Xi
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Wang
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Yu
authors.forename: Hong-Xiang
authors.initials: HX
authors.lastname: Lou
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D001632:Bibenzyls / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000187:drug effects; D037961:Frullania / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D014961:X-Ray Diffraction
chemical_list: D000970:Antineoplastic Agents; D001632:Bibenzyls; D004224:Diterpenes