Chromone derivative with a spiro[chromene-5,2′-furan] ring and sesquiterpenoids from the marine algicolous Trichoderma asperellum Z54–7

A novel chromone derivative with a unique carbon skeleton, trichochromone A (1), a new trichothecene sesquiterpenoid, trichodermarin O (2), and two new farnesane-type sesquiterpenoids, trichodersanins A and B (3 and 4), were isolated from the fungus Trichoderma asperellum Z54-7 obtained from the surface of marine red alga Hyalosiphonia caespitosa. Their structures and configurations were elucidated by detailed spectroscopic analysis and single-crystal X-ray diffraction. Trichochromone A (1) features a spiro[chromene-5,2'-furan] ring. Trichodermarin O (2) is the second trichothecene derivative with an aminosugar unit. Compounds 1 and 3/4 exhibited weak inhibition against one marine phytoplankton species, Chattonella marina.