Makoto Kuramoto

Halichlorine, an inhibitor of VCAM-1 induction from the marine sponge Halichondria okadai Kadata

Abstract The novel alkaloid halichlorine was isolated from Halichondria okadai Kadota and its structure was elucidated by spectroscopic analysis. The relative stereochemistry was clarified by a detailed analysis of coupling constants and the NOESY spectrum. Halichlorine significantly inhibits VCAM-1 induction in cultured HUVE (human umbilical vein endothelial) cells.

ISOLATION AND STRUCTURE OF PINNATOXIN D, A NEW SHELLFISH POISON FROM THE OKINAWAN BIVALVE PINNA MURICATA

Abstract A new shellfish poison, pinnatoxin D, has been isolated from the Okinawan bivalve Pinna muricata . The planar structure was elucidated by extensive 2D NMR experiments, and the relative stereochemistry was deduced by NOESY data and 3 J HH coupling constants. Pinnatoxin D is a novel amphoteric carbocyclic compound which is composed of a 6,7-spiro ring, a 5,6-bicyclo ring and a 6,5,6-trispiro ketal involving 15 chiral centers.

Pinnaic acid and tauropinnaic acid: Two novel fatty acids composing a 6-azaspiro[4.5]decane unit from the Okinawan bivalve Pinna muricata

Abstract Two novel fatty acids with cPLA 2 inhibitory activity, pinnaic acid and tauro-pinnaic acid, were isolated from the Okinawan bivalve Pinna muricata . Their structures, including the relative stereochemistry at C5, C9, C13 and C14, were elucidated by extensive 2D NMR spectroscopic analysis.

Absolute stereochemistry of halichlorine; A potent inhibitor of VCAM-1 induction

Abstract The absolute stereochemistry of a marine alkaloid halichlorine, which significantly inhibits VCAM-1 induction in HUVE cells, was established by synthesis of a degradation product of natural product.

Microwave plasma in hydrocarbon liquids

The generation of microwave plasma in liquid with vapor bubbles has been achieved and will soon be applied to high-speed chemical vapor deposition. Vapor bubbles are induced from an electrode by heating. The deposition rate of diamondlike carbon films depends on the pressure and the power of the microwave supply. Polycrystalline silicon carbide is synthesized on a silicon substrate in a mixture of n-dodecane and silicone oil. The dispersion of water droplets in liquid creates many pores on the silicon carbide films. The synthesis of carbon nanotubes can be achieved in liquid benzene.

ABSOLUTE CONFIGURATION OF NORZOANTHAMINE, A PROMISING CANDIDATE FOR AN OSTEOPOROTIC DRUG

Abstract The absolute configuration of norzoanthamine ( 1 ) was determined to be 2 R 4 S , 6 S , 9 S , 10 R , 12 S , 13 R , 18 S , 21 S , and 22 S based on 1 H NMR spectral data of the MTPA esters of norzoamthamine derivatives. The possible biogenesis of zoanthamines is also proposed.

Radio frequency plasma in water

We generate a radio frequency (RF) plasma in water at an atmospheric pressure by applying an RF power of 13.56 MHz from an electrode. The plasma is in a bubble formed in water. On the basis of hydrogen spectral lines under the assumption of thermal equilibrium, the temperature of the plasma is estimated to be 4000–4500 K. Spectroscopic measurements show that hydrogen and oxygen are excited in the plasma. The plasma is also obtained in tap water or NaCl solution with a high conductivity. In the solution, sodium spectral lines are observed. Colored water containing methylene blue is exposed to the plasma. The absorbence spectra of the colored water before and after exposure to the plasma suggest the decomposition of organic matter due to chemical reactions involving active species, such as OH-radicals.

Three novel anti-microfouling nitroalkyl pyridine alkaloids from the Okinawan marine sponge Callyspongia sp

Abstract Three novel nitroalkyl pyridine alkaloids, untenines A, B and C, with anti-microfouling activity, were first isolated from the Okinawan marine sponge Callyspongia sp. Their structures were elucidated on the basis of spectroscopic methods. The synthesis of untenine A was also carried out.

Cylindradines A and B: Novel Bromopyrrole Alkaloids from the Marine Sponge Axinella cylindratus

The novel alkaloids cylindradines A and B were isolated from Axinella cylindratus, and their structures were elucidated by spectroscopic analyses. Stereochemistries of these compounds were determined by X-ray analysis. Cylindradines showed moderate inhibitory activity against the murine leukemia cell line P388.

Isolation and structural elucidation of a growth stimulant for arbuscular mycorrhizal fungus from Laminaria japonica Areschoug

Arbuscular Mycorrhizal (AM) fungi enhance terrestrial plant growth by forming a symbiotic relationship with the roots of its host plant. A growth stimulant for AM fungi was isolated from a brown alga Laminaria japonica Areschoug. The active substance for in vitro AM hyphal growth was isolated from 75% methanol extracts of L. japonica using a succession of chromatographic procedures, including flash chromatography equipped with an octa decyl silane (ODS) column, gel filtration chromatography and HPLC using an ODS column. Spores of Gigaspora margarita Becker & Hall, an AM fungus, were exposed to the compound in vitro, and hyphal growth of G. margarita was measured after two weeks of incubation. At 40 mg L−1, the compound significantly stimulated the in vitro hyphal growth of G. margarita, compared to the control. This compound was elucidated as 5′-deoxy-5′-methylamino-adenosine by EIMS and NMR spectrum.