title: Guanacastane diterpenoids from the plant endophytic fungus Cercospora sp.
abstract: Cercosporenes A-F (1-6, respectively), six new guanacastane diterpenes, including a homodimer (5) and a heterodimer (6), were isolated from the crude extract of the fungus Cercospora sp., endophytic to the medicinal plant Fallopia japonica. The structures of 1-6 were elucidated by nuclear magnetic resonance experiments, and 4 and 5 were further confirmed by X-ray crystallography. The absolute configuration of 1 and 3 was assigned by electronic circular dichroism calculations, whereas that of 6 was deduced by the application of the circular dichroism exciton chirality method. In addition to its cytotoxicity against a panel of five human tumor cell lines, HeLa, A549, MCF-7, HCT116, and T24, heterodimer 6 also induced autophagy in HCT116 cells.
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100190, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Feng
authors.forename: Fengxia
authors.initials: F
authors.lastname: Ren
authors.forename: Shubin
authors.initials: S
authors.lastname: Niu
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Liu
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Che
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001203:Ascomycota / Q000737:chemistry*; D002681:China; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D045468:Fallopia japonica / Q000382:microbiology; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D008968:Molecular Conformation; D015394:Molecular Structure; D018515:Plant Leaves / Q000382:microbiology; D010946:Plants, Medicinal / Q000382:microbiology; D013237:Stereoisomerism
chemical_list: D000970:Antineoplastic Agents; D004224:Diterpenes; C000589780:cercosporene F