title: A new dihydroxanthenone from a plant-associated strain of the fungus Chaetomium globosum demonstrates anticancer activity.
abstract: Bioassay-guided fractionation of a cytotoxic EtOAc extract of the fungal strain, Chaetomium globosum, inhabiting the rhizosphere of the Christmas cactus, Opuntia leptocaulis, of the Sonoran desert afforded a new dihydroxanthenone, globosuxanthone A (1), a new tetrahydroxanthenone, globosuxanthone B (2), two new xanthones, globosuxanthone C (3) and D (4), 2-hydroxyvertixanthone (5), and two known anthraquinones (6 and 7). The structures of the new compounds 1-4 were elucidated by NMR and MS techniques, and the relative stereochemistry of 1 was determined by X-ray crystallographic analysis. Of the compounds encountered, 1 was found to exhibit strong cytotoxicity against a panel of seven human solid tumor cell lines, disrupt the cell cycle leading to the accumulation of cells in either G2/M or S phase, and induce classic signs of apoptosis.
authors.affiliation: Southwest Center for Natural Products Research and Commercialization, Office of Arid Lands Studies, College of Agriculture and Life Sciences, The University of Arizona, 250 E. Valencia Road, Tucson, AZ 85706-6800, USA.
authors.forename: E M Kithsiri
authors.initials: EM
authors.lastname: Wijeratne
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Turbyville
authors.forename: Anne
authors.initials: A
authors.lastname: Fritz
authors.forename: Luke
authors.initials: L
authors.lastname: Whitesell
authors.forename: A A Leslie
authors.initials: AA
authors.lastname: Gunatilaka
mesh_terms: D000880:Anthraquinones; D000970:Antineoplastic Agents / Q000302:isolation & purification* / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002597:Chaetomium / Q000737:chemistry*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015394:Molecular Structure; D013237:Stereoisomerism; D014966:Xanthenes / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000880:Anthraquinones; D000970:Antineoplastic Agents; D014966:Xanthenes