Takuma Sasaki

Purealidins B and C, new bromotyrosine alkaloids from the okinawan marine sponge Psammaplysilla purea

New bromotyrosine-derived alkaloids, purealidins B (1) and C (2), have been isolated from the Okinawan marine sponge Psammaplysilla purea and their structures elucidated on the basis of spectroscopic data. Purealidin B (1) showed antibacterial activity, while purealidin C (2) exhibited antifungal and antineoplastic activities.

Fellutamides A and B, cytotoxic peptides from a marine fish-possessing fungus Penicillium fellutanum

Abstract Two cytotoxic peptides, fellutamides A and B, have been isolated from the cultured fungus Penicillium fellutanum Biourge which was isolated from the gastrointestine of the marine fish Apogon endekataenia Bleeker, and the structures were elucidated to be 1 and 2 by two-dimensional NMR and FAB MS/MS data.

Iejimalides C and D, new antineoplastic 24-membered macrolide sulfates from the okinawan marine tunicate Eudistoma cf. rigida

Abstract Two new 24-membered macrolide sulfates, iejimalides C ( 1 ) and D ( 2 ), with antineoplastic activity have been isolated from the Okinawan marine tunicate Eudistoma cf. rigida . The structures were elucidated on the basis of spectroscopic data.

Nakijiquinones A and B, new antifungal sesquiterpenoid quinones with an amino acid residue from an Okinawan marine sponge

Abstract Two new sesquiterpenoid quinones with an amino acid residue, nakijiquinones A (1) and B (2), have been isolated from an Okinawan marine sponge

Brasiliquinones A–C, new cytotoxic benz[a]anthraquinones with an ethyl group at C-3 from actinomycete Nocardia brasiliensis

Three new cytotoxic benz[a]anthraquinones with an ethyl group at C-3, brasiliquinones A–C 1–3, have been isolated from the actinomycete Nocardia brasiliensis IFM 0089, and their structures elucidated on the basis of spectroscopic data and by chemical means. Brasiliquinone A 1 is the first benz[a]anthraquinone possessing ristosamine as an O-glycoside moiety, while brasiliquinones B 2 and C 3 correspond to the aglycone of 1 and the 8-O-methyl derivative of 2, respectively.

Stelliferins A-F, new antineoplastic isomalabaricane triterpenes from the Okinawan marine sponge Jaspis stellifera

Abstract Six new antineoplastic isomalabaricane-type triterpenes, stelliferins A–F, have been isolated from the Okinawan marine sponge Jaspis stellifera . The structures were established by spectroscopic analyses, espesially 1D and 2D NMR techniques. The stereostructures have been elucidated by NOESY spectra as well as chemical degradation experiments.

Niphatesines A–D, new antineoplastic pyridine alkaloids from the okinawan marine sponge Niphates sp.

Four new pyridine alkaloids, niphatesines A–D (1–4), with potent antineoplastic activity were isolated from the Okinawan marine sponge Niphates sp. and their structures were elucidated on the basis of spectroscopic data.

Niphatesines E–H, new pyridine alkaloids from the Okinawan marine sponge Niphates sp.

Four new mono-3-alkyl-substituted pyridine alkaloids, niphatesines E–H (1–4), possessing oxime methyl ether or methoxyamine functionality have been isolated from the Okinawan marine sponge Niphates sp. and the structures elucidated by spectral and chemical means. These pyridine alkaloids exhibited cytotoxic and antimicrobial activities.

Hymenamides G, H, J, and K, four new cyclic octapeptides from the Okinawan marine sponge Hymeniacidon sp.

Abstract Four new cyclic octapeptides, hymenamides G, H, J, and K, (1–4), have been isolated from the Okinawan marine sponge Hymeniacidon sp. and the structures elucidated on the basis of 2D NMR data and Edman degradation experiments of their partial hydrolysis products.

Plakotenin, a new cytotoxic carboxylic acid from the okinawan marine sponge plakortis Sp.

Plakotenin, a new carboxylic acid with cytotoxic activity was isolated from the Okinawan marine sponge Plakortis sp. and the structure elucidated on the basis of spectroscopic data.