Author(s): Wijeratne EM, Turbyville TJ, Fritz A, Whitesell L, Gunatilaka AA
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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.
This article was published in Bioorg Med Chem
and referenced in Biochemistry & Analytical Biochemistry