Four New Cytotoxic Arborinane-Type Triterpenes from the Endolichenic Fungus Myrothecium inundatum

Abstract

Two new arborinane-type triterpenes, myrotheols A (1) and B (2), two new arborinane-type glycosides, myrothesides C (3) and D (4), together with four known diterpenes (5 – 8) were isolated from the ethyl acetate extract of the endolichenic fungus Myrothecium inundatum. The structures of new compounds 1 – 4 were elucidated by NMR and MS analyses. The absolute configuration of 1 was assigned by a single-crystal X-ray diffraction experiment. Compounds 3 and 4 represent the first two natural 4-O-methyl-α-D-mannosides. Compounds 1 – 8 exhibited cytotoxicity against K562 and RKO human cancer cell lines.

Key words

endolichenic fungi - Myrothecium inundatum - Stachybotryaceae - arborinane-type - riterpenes - diterpenes - cytotoxicity

^* These authors contributed equally to this work.

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