Jun'ichi Kobayashi

Keramamine-A and -B, novel antimicrobial alkaloids from the Okinawan marine sponge Pellina sp.

Abstract Keramamine-A and -B, two new β-carboline alkaloids with a 13 membered ring have been isolated from the Okinawan marine sponge Pellina sp. as antimicrobial substances and the structures of keramamine-A and -B have been determined by X-ray analysis and by spectral and chemical means, respectively.

Isolation and structure of aaptamine a novel heteroaromatic substance possessing α-blocking activity from the sea sponge Aaptos aaptos

A novel heteroaromatic substance, aaptamine possessing an α-adrenoceptor blocking activity has been isolated from the tropical sea sponge Aaptos aaptos and its structure has been determined to be 1 on the basis of spectral data and chemical degradation.

The amino acid sequences of homologous hydroxyproline‐containing myotoxins from the marine snal Conus geographus venom

These peptides inhibit the contractile response of directly stimulated mouse diaphragm.

A novel antagonist of serotonergic receptors, hymenidin, isolated from the Okinawan marine sponge Hymeniacidon sp.

A novel bromine-containing pyrrole compound, hymenidin, has been isolated from the Okinawan marine spongeHymeniacidon sp. as a potent antagonist of serotonergic receptors and its structure elucidated using spectral data.

Prianosin A, a novel antileukemic alkaloid from the okinawan marine sponge Prianos melanos

Abstract A novel alkaloid, prianosin A (1), with potent antineoplastic activity has been isolated from the Okinawan marine sponge Prianos melanos. Its absolute stereostructure was determined by single crystal x-ray diffraction analysis.

Theonelladins A ∼ D, novel antineoplastic pyridine alkaloids from the Okinawan marine sponge Theonella swinhoei

Abstract Novel pyridine alkaloids, theonelladins A ∼ D, with potent antileukemic activity have been isolated from the Okinawan marine sponge Theonella swinhoei and the structures elucidated on the basis of spectroscopic data.

Keramadine, a novel antagonist of serotonergic receptors isolated from the okinawan sea sponge Agelas sp.☆

Abstract A new bromine-containing alkaloid, keramadine, has been isolated from the Okinawan sea sponge Agelas sp. as a novel antagonist of serotonergic receptors and its structure has been elucidated by n.m.r. spectrometry.

Eudistomidin-A, a novel calmodulin antagonist from the okinawan tunicate eudistoma glaucus

Eudistomidin-A, a novel indole alkaloid having calmodulin-antagonistic activity has been isolated from the Okinawan tunicate Eudistoma glaucus and the structure determined to be 1 on the basis of the spectral data and chemical derivatization.

Amphidinolide-A, a novel antineoplastic macrolide from the marine dinoflagellate Amphidinium sp.

Abstract A novel 20-membered macrolide, amphidinolide-A with antineoplastic activity has been isolated from the marine dinoflagellate Amphidinium sp. and its structure was determined to be 1 by spectral data.

Purealin, a novel enzyme activator from the Okinawan marine sponge Psammaplysilla purea

Purealin , a novel secondary metabolite, which modurates enzymic reactions of ATPases, has been isolated from the okinawan marine sponge Psammaplysilla purea and the structure has been determined by the 1H-1H homonuclear and 1H-13C heteronuclear NMR chemical shift correlations and CD spectra.