Taro Amagata

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Five novel metabolites, trichodenones A-C (1-3), harzialactone A (4) and B (5), have been isolated together with known R-mevalonolactone (6) from the culture broth of a strain of Trichoderma harzianum OUPS-N115 originally separated from the sponge Halichondria okadai. Their structures have been elucidated by spectral evidence. Among them, 1-3 exhibited(More)
Saltwater culture of Myrothecium verrucaria, separated from a Spongia sp. collected in Hawaii, was a source of three new trichothecenes, 3-hydroxyroridin E (1a), 13'-acetyltrichoverrin B (2), and miophytocen C (3) and nine known related compounds (1b, 4, 5, 6, 7a, 7b, 8, 9a, and 9b). The stereostructures of the new compounds were established on the basis of(More)
Two novel cyclic depsipeptides, guangomides A (1) and B (2), together with a new destruxin derivative (3) were isolated from the cytotoxic extract obtained from the saltwater culture of an unidentifiable sponge-derived fungus. The new structures were elucidated on the basis of analysis of extensive 1D and 2D NMR data sets, and the absolute configurations of(More)
[structure: see text] Structurally unique steroids, isocyclocitrinol A (1) and 22-acetylisocyclocitrinol A (2), were isolated from the extract of a saltwater culture of sponge-derived Penicilliun citrinum. The structures were established by analysis of 1D and 2D NMR data. The absolute structures were determined on the basis of X-ray structure analysis and(More)
The Halichondria sponge-derived fungus, Gymnacella dankaliensis, was cultured in two different media conditions. A modified malt extract medium containing soluble starch instead of glucose resulted in two extremely unusual steroids, dankasterones A (2) and B (3), while four additional unusual steroids, gymnasterones A (4), B (5), C (6), and D (7), were(More)
Gymnastatins F -H (2-4) and gymnamide (5) have been isolated from the mycelial MeOH extract of the Halichondria sponge-derived fungus Gymnascella dankaliensis. Their stereostructures have been established on the basis of spectroscopic analyses using 1D and 2D NMR techniques. The stereochemistry of gymnastatin H (4) was determined by its synthesis. Among(More)
Four new metabolites, gymnastatins Q ( 3) and R ( 4) and dankastatins A ( 5) and B ( 6), have been isolated from the mycelial MeOH extract of a fungal strain of Gymnascella dankaliensis separated from a Halichondria sponge. Their stereostructures have been established on the basis of spectroscopic analysis using 1D and 2D NMR techniques. All of the isolated(More)
The structures and biological properties of peptides produced by two genera of marine-derived fungi, an atypical Acremonium sp., and a Metarrhizium sp. were explored. The Acremonium strain was isolated from a marine sponge and has previously been shown by our group to produce peptides from the efrapeptin and RHM families. The isolation and structure(More)
The sponge-derived polyketide macrolides fijianolides A (1) and B (2), isolaulimalide and laulimalide, have taxol-like microtubule-stabilizing activity, and the latter exhibits potent cytotoxicity. Insight on the biogeographical and phenotypic variations of Cacospongia mycofijiensis is presented that will enable a future study of the biosynthetic pathway(More)