title: Smardaesidins A-G, isopimarane and 20-nor-isopimarane diterpenoids from Smardaea sp., a fungal endophyte of the moss Ceratodon purpureus.
abstract: Five new isopimarane diterpenes, smardaesidins A-E (1- 5) and two new 20-nor-isopimarane diterpenes, smardaesidins F (6) and G (7), together with sphaeropsidins A (8) and C-F (10-13) were isolated from an endophytic fungal strain,  Smardaea  sp. AZ0432, occurring in living photosynthetic tissue of the moss  Ceratodon purpureus . Of these, smardaesidins B (2) and C (3) were obtained as an inseparable mixture of isomers. Chemical reduction of sphaeropsidin A (8) afforded sphaeropsidin B (9), whereas catalytic hydrogenation of 8 yielded 7-O-15,16-tetrahydrosphaeropsidin A (14) and its new derivative, 7-hydroxy-6-oxoisopimara-7-en-20-oic acid (15). The acetylation and diazomethane reaction of sphaeropsidin A (8) afforded two of its known derivatives, 6-O-acetylsphaeropsidin A (16) and 8,14-methylenesphaeropsidin A methyl ester (17), respectively. Methylation of 10 yielded sphaeropsidin C methyl ester (18). The planar structures and relative configurations of the new compounds 1-7 and 15 were elucidated using MS and 1D and 2D NMR experiments, while the absolute configurations of the stereocenters of 4 and 6-8 were assigned using a modified Mosher's ester method, CD spectra, and comparison of specific rotation data with literature values. Compounds 1-18 were evaluated for their potential anticancer activity using several cancer cell lines and cells derived from normal human primary fibroblasts. Of these, compounds 8, 11, and 16 showed significant cytotoxic activity. More importantly, sphaeropsidin A (8) showed cell-type selectivity in the cytotoxicity assay and inhibited migration of metastatic breast adenocarcinoma (MDA-MB-231) cells at subcytotoxic concentrations.
authors: SW Center for Natural Products Research and Commercialization, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, 250 E. Valencia Road, Tucson, Arizona 85706-6800, United States.
authors: Xiao-Ning
authors: XN
authors: Wang
authors: Bharat P
authors: BP
authors: Bashyal
authors: E M Kithsiri
authors: EM
authors: Wijeratne
authors: Jana M
authors: JM
authors: U'Ren
authors: Manping X
authors: MX
authors: Liu
authors: Malkanthi K
authors: MK
authors: Gunatilaka
authors: A Elizabeth
authors: AE
authors: Arnold
authors: A A Leslie
authors: AA
authors: Gunatilaka
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D019068:Bryopsida / Q000382:microbiology*; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D060026:Endophytes / Q000737:chemistry*; D005260:Female; D006801:Humans; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism
chemical_list: D000970:Antineoplastic Agents; D004224:Diterpenes; C568758:smardaesidin A