Mitsugi Kozawa

Chalcones from Angelica keiskei

Abstract Four new chalcones, xanthangelols B–E were isolated from roots of Angelica keiskei and their structures determined to be 2′,4,4′-trihydroxy-3′-[( E )-6-hydroxy-3,7-dimethyl-2,7-octadienyl]chalcone, 2′,4,4′-trihydroxy-3′-[( E )-3-methy]-6-oxo-2-hexenyl]chalcone, 2′,4-dihydroxy-4′-methoxy-3′-(2-hydroxy-3-methyl-3-butenyl)chalcone and 2′,4-dihydroxy-4′-methoxy-3′-(2-hydroperoxy-3-methyl-3-butenyl)chalcone, respectively, by means of chemical and spectral analyses.

Coumarin glycosides from Edgeworthia chrysantha

Abstract Rutarensin and two new coumarins, edgeworoside B and C, were isolated from the root and stem of Edgeworthia chrysantha ( E. papyrifera ). The structures of edgeworoside B and C were determined as 3-(7-coumarinyloxy)-8-(7-hydroxycoumarin-8-yl)-7-β- d -apiofranosyloxycoumarin and 8-(7-hydroxycoumarin-8-yl)-7-α- l -rhamnopyranosyloxycoumarin.

Inhibition of gastric H+,K+-ATPase and acid secretion by cassigarol A, a polyphenol from Cassia garrettiana Craib

The effects of cassigarol A, a naturally occurring polyphenol, on gastric H+,K(+)-ATPase and gastric acid secretion were studied. Cassigarol A inhibited H+,K(+)-ATPase and K-stimulated p-nitrophenyl phosphatase from hog gastric mucosa with 50% inhibition of 1.2 x 10(-6) and 6.3 x 10(-6) M, respectively. The kinetic study showed that the inhibition of H+,K(+)-ATPase by cassigarol A was competitive with respect to ATP and non-competitive with respect to K+. Cassigarol A inhibited both H+,K(+)-ATPase-mediated proton transport and 2-deoxy-D-glucose-induced acid secretion. On the other hand, cassigarol A acetate, in which phenolic hydroxy groups are acetylated, was not effective in the inhibition of enzyme activity and acid secretion. These results indicate that cassigarol A is a potent inhibitor of gastric H+,K(+)-ATPase, that the anti-secretory activity of cassigarol A is related to the inhibition of H+,K(+)-ATPase and that an important moiety of cassigarol A in the interaction with the enzyme is the phenolic hydroxy groups.

Biflavonoids from Daphne odora

Abstract Two new biflavonoids, daphnodorins E and F, were isolated from the roots of Daphne odora and their structures established from spectral and chemical evidence.

A spirobiflavonoid genkwanol B from Daphne genkwa

Abstract A novel biflavonoid, genkwanol B, was isolated from the roots of Daphne genkwa . The structure of genkwanol B was determined on the basis of chemical studies and spectroscopic data, including NOESY and HMBC experiments.

THREE BIFLAVONOIDS FROM WIKSTROEMIA SIKOKIANA

Abstract Three new biflavonoids, sikokianin C, and wikstrols A and B, were isolated from the roots of Wikstroemia sikokiana and their structures established by chemical and spectroscopic means.

A third spirobiflavonoid genkwanol C from Daphne genkwa

Abstract A novel biflavonoid, genkwanol C, was isolated from the roots of Daphne genkwa . The absolute structure of genkwanol C was determined on the basis of spectroscopic data including CD spectrum and modified Moshers method.

Stilbenoids from Cassia garrettiana

Abstract Three new stilbenoids, cassigarols E-G, were isolated from the Thai crude drug, ‘Sa mae sarn’ (the heartwood of Cassia garrettiana ) and their structures were established from spectral and chemical evidences.

Chromones from Cnidium monnieri

Abstract Four new chromones, cnidimol C–F, along with cnidimol A, cnidimol B and karenin were isolated from the aerial parts of Cnidium monnieri . The structures of the new chromones were determined to be 5,7-dihydroxy-2-hydroxy-methylchromone, 5,7-dihydroxy-6-[(2 Z )-3-hydroxymethyl-2-butenyl]-2-hydroxymethylchromone, 5,7-dihydroxy-6-[2-hydroxy-3-methyl-3-butenyl]- 2-hydroxymethylchromone and 5,8-dihydroxy-2-hydroxymethyl-8-methyl-4 H ,9 H -pyrano [3,2- h ][1]benzoxepin-4-one.

Isocoumarins from Coriandrum sativum

Abstract Two new isocoumarins, coriandrone A and B, were isolated from the aerial parts of Coriandrum sativum together with two known isocoumarins, coriandrin and dihydrocoriandrin. Their structure were established by spectroscopic means and X-ray analysis.