Yasushi Ohizumi

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.

Ascididemin, a novel pentacyclic aromatic alkaloid with potent antileukemic activity from the Okinawan tunicate Didemnum sp.

Abstract A novel pentacyclic aromatic alkaloid, ascididemin (1), with potent antineoplastic activity has been isolated from the Okinawan tunicate Didemnum sp. Its structure was elucidated on the basis of spectroscopic data.

Ageliferins, potent actomyosin Atpase activators from the Okinawan marine sponge Agelas sp

Abstract Three bromopyrrole alkaloids, ageliferin (1), bromoageliferin (2), and dibromoageliferin (3), have been isolated as potent actomyosin ATPase activators from the Okinawan marine sponge Agelas sp. and the structures elucidated on the basis of spectral data, especially two dimensional NMR spectra.

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.

Agelasine-A, -B, -C and -D, novel bicyclic diterpenoids with a 9-methyladeninium unit possessing inhibitory effects on na,K-atpase from the okinawa sea sponge Agelas sp.1)

Abstract Agelasine-A, -B, -C and -D, novel bicyclic diterpenoids having inhibitory effects on enzymic reactions of Na,K-ATPase, have been isolated from the orange colored Okinawan sea sponge Agelas sp. and the structures have been determined on the basis of their spectral data and chemical conversions.

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.