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Biomedical subjects

A Umeyama

Publications and source records attributed to A Umeyama.

At least 19 recordsLinked to original sources
PubMed2000

New 24-isopropylcholesterol and 24-isopropenylcholesterol sulfate from the marine sponge Epipolasis species.

Two novel steroids, polasterol A (1) and polasterol B sulfate (2), along with two known compounds, 22(E),24-isopropylcholesta-5, 22-dien-3 beta-ol (3) and halistanol sulfate (4), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1 and 2 were determined as 3 beta-hydroxy-24-isopropylcholesta-5, 22(E)-dien-7-one and 24xi-isopropenylcholesta-22(Z), 28(29)-diene-2 beta,3 alpha,6 alpha-triyl trisodium sulfate on the basis of spectroscopic investigations and a chemical conversion.

Animals↗
PubMed2000

Two new 26,27-cyclosterols from the marine sponge Strongylophora corticata.

Two novel steroids with a cyclopropane ring at C-25 and C-26, 7-oxopetrosterol (1) and 7alpha-hydroxypetrosterol (2), along with two known compounds, petrosterol (3) and 23,24-dihydrocalysterol (4), have been isolated from the Japanese marine sponge Strongylophora corticata. The structures of 1 and 2 were determined as 26, 27-cyclo-24,27-dimethyl-3beta-hydroxycholest-5-en-7-one and 26, 27-cyclo-24,27-dimethylcholest-5-en-3beta,7alpha-diol on the basis of spectroscopic investigations.

Animals↗
PubMed1998

Peroxypolasol and mugipolasol: two novel diterpenes from the marine sponge epipolasis sp

Two novel diterpenes, peroxypolasol (1) and mugipolasol (2), have been isolated from the Japanese marine sponge Epipolasis sp. The structures of 1 and 2 were determined on the basis of spectroscopic data. Compound 1 is a diterpene with a peroxide ring in the side chain, and 2 is an unusual six/five-membered ring diterpene with an ethyl unit at C-2.

Journal Article↗
PubMed1995

Mechanism of inhibition of IgE-dependent histamine release from rat mast cells by penasterol and penasterone.

Penasterol and penasterone, constituents of the Okinawan marine sponge Penares incrustans, dose-dependently inhibited anti-IgE-induced histamine release from rat mast cells. The concentrations of penasterol and penasterone required for 50% inhibition of anti-IgE-induced histamine release (IC50) were 0.5 and 1.5 microM, respectively. Both compounds dose-dependently inhibited phospholipase A2 (PLA2) activity. Moreover, they inhibited anti-IgE-induced [3H]arachidonic acid from rat mast cells. These results suggest that the mechanism of inhibition by these compounds of the histamine release induced by anti-IgE was through the inhibition of PLA2.

Animals↗
PubMed1994

Potent inhibitors of histamine release: polyhydroxylated sterols from the Okinawan soft coral Sinularia abrupta.

A new polyhydroxylated steroid (24-methylene-1 alpha, 3 beta, 11 alpha-trihydroxycholest-5-ene-18-oic acid-3-acetate, 1) and known related compounds (2-4) from the soft coral Sinularia abrupta have potently inhibited histamine release from rat peritoneal mast cells induced by anti-immunoglobulin E. The inhibitory effect of 1 was approximately 6500 times stronger than that of disodium cromoglycate, a well-known antiallergic drug.

Animals↗
PubMed1994

Triterpenoid glycosides from Anagallis arvensis.

From the herb of Anagallis arvensis, we have isolated four novel oleanane glycosides, anagallosaponins VI-IX, and two artifact saponins, apoanagallosaponins III and IV, formed from anagallosaponins III and IV. The structures were elucidated by chemical and spectral methods, 2D NMR techniques being particularly helpful. The structures of anagallosaponins VI and VII were characterized as priverogenin B 3-O-beta-D-xylopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-alpha-L-arabinopyranoside and 3-O-(beta-D-glucopyranosyl (1-->4)-[beta-D-xylopyranosyl (1-->2)]beta-D-glucopyranosyl (1-->4)-alpha-L-arabinopyranoside), respectively. The structures of anagallosaponins VIII and IX were characterized as 23-hydroxypriverogenin B 22-acetate 3-O-(beta-D-xylopyranosyl (1-->2)-O-beta-D-glucopyranosyl (1-->4)[beta-D-glucopyranosyl (1-->2)]-alpha-L-arabinopyranoside), 3-O-(beta-D-glucopyranosyl (1-->4)-[beta-D-xylopyranosyl (1-->2)]beta-D-glucopyranosyl (1-->4)[beta-D-glucopyranosyl (1-->2)]- alpha-L-arabinopyranoside), respectively. The structures of apoanagallosaponins III and IV were characterized as camelliagenin A 16-acetate 3-O-beta-D-xylopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-alpha-L-arabnopyranoside, 3-O-(beta-D-xylopyranosyl (1-->2)-O-beta-D-glucopyranosyl (1-->4)[beta-D-glucopyranosyl (1-->2)]-alpha-L-arabinopyranoside), respectively.

Carbohydrate Conformation↗
PubMed1994

Baccharane glycosides from seeds of Impatiens balsamina.

From the seeds of Impatiens balsamina have been isolated four rare baccharane glycosides, hosenkosides L-O. The structures of all isolates were secured by the use of 2D NMR techniques (1H-1H COSY, HMQC, HMBC, ROESY) and chemical derivatization. Hosenkosides L and M are hosenkol A 3-O-sambubiosyl-28-O-glucoside and 3-O-sambubiosyl-26-O-glucosyl-28-O-glucoside, respectively. Hosenkoside N is hosenkol C 3-O-glucosyl-28-O-glucoside. Hosenkoside O is hosenkol D 3-O-sophorosyl-28-O-glucoside.

Glycosides↗
PubMed1994

Hosenkosides F, G, H, I, J, and K, novel baccharane glycosides from the seeds of Impatiens balsamina.

From the seeds of Impatiens balsamina we have isolated six novel baccharane glycosides, hosenkosides F-K. The structures of all isolates were determined by the use of two dimensional (2D) NMR techniques (1H-1H correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC), rotating frame Overhauser enhancement spectroscopy (ROESY), total correlation spectroscopy (TOCSY)) and chemical derivatization. Hosenkosides F, H and I are hosenkol B 3-O-sambubiosido-26-O-glucoside, 3-O-sambubioside and 3,26-O-diglucoside, respectively. Hosenkoside G is hosenkol C 3-O-sambubiosido-28-O-glucoside. Hosenkosides J and K are hosenkol A 3-O-sophoroside and 3-O-sophorosido-26-O-glucosyl-28-O-glucoside, respectively.

Carbohydrate Sequence↗
PubMed1994

Structures of anagallosaponins I-V and their companion substances from Anagallis arvensis L.

From the herb of Anagallis arvensis L., we have isolated five novel oleanane glycosides, anagallosaponins I-V and the artifact, methyl anagallosaponin I, besides anagallosides A, B, C, and desglucoanagallosides A and B. The structures of isolates were identified by the use of 2D-NMR techniques (1H-1H correlation spectroscopy (COSY), 1H-detected heteronuclear multiple quantum coherence (HMQC), heteronuclear multiple quantum coherence (HMBC), rotating frame Overhauser enhancement spectroscopy (ROESY), total correlation spectroscopy (TOCSY). The structures of anagallosaponins I and II were characterized as anagallogenin A. 3-O-(beta-D-glucopyranosyl (1-->4)-[beta-D-xylopyranosyl (1-->2)-] beta-D-glucopyranosyl (1-->4)- [beta-D-glucopyranosyl (1-->2)]-alpha-L-arabinopyranoside) and anagallogein A 22-acetate 3-O-(beta-D-xylopyranosyl (1-->2)-O-beta-D- glucopyranosyl (1-->4)-[beta-D-glucopyranosyl (1-->2)]-alpha-L-arabinopyranoside), respectively. The structures of anagallosaponins III, IV and V were characterized as priverogenin B 22-acetate 3-O-beta-D-xylopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-alpha-L-arabinopyranoside, 3-O-(beta-D-xylopyranosyl (1-->2)-beta-D-glucopyranosyl (1-->4)-[beta-D-glucopyranosyl (1-->2)]-alpha-L-arabinopyranoside), 3-O-(beta-D-glucopyranosyl (1-->4)-[beta-D-xylopyranosyl (1-->2)]-beta-D-glucopyranosyl (1-->4)-alpha-L-arabinopyranoside), respectively. Methyl anagallosaponin I, the methylacetal of anagallosaponin I might be derived from anagallosaponin I during the isolation procedure.

Carbohydrate Conformation↗
PubMed1993

Mechanism of inhibition of IgE-dependent histamine release from rat mast cells by xestobergsterol A from the Okinawan marine sponge Xestospongia bergquistia.

Histamine release from rat peritoneal mast cells induced by anti-IgE was essentially complete within 4-5 min. Xestobergsterol A and B, which are constituents of the Okinawan marine sponge Xestospongia bergquistia Fromont, dose-dependently inhibited anti-IgE-induced histamine release from rat mast cells. The IC50 values of xestobergsterol A and B for histamine release in mast cells activated by anti-IgE were 0.07 and 0.11 microM, respectively. Anti-IgE stimulated PI-PLC activity in a mast cell membrane preparation. Xestobergsterol A dose-dependently inhibited the generation of IP3 and membrane-bound PI-PLC activity. Moreover, xestobergsterol A inhibited Ca(2+)-mobilization from intracellular Ca(2+)-stores as well as histamine release in mast cells activated by anti-IgE. On the other hand, xestobergsterol B did not inhibit the membrane-bound and cytosolic PI-PLC activity, IP3 generation or the initial rise in [Ca2+]i in mast cells activated by anti-IgE. These results suggest that the mechanism of inhibition by xestobergsterol A of the initial rise in [Ca2+]i, of the generation of IP3, and of histamine release induced by anti-IgE, was through the inhibition of PI-PLC activity.

Animals↗
PubMed1993

Histamine release from rat mast cells induced by the inhibition of adenosinetriphosphatase for Na and K channels.

6-Tridecylresorcylic acid (TRA) caused histamine release from rat peritoneal mast cells in a dose-dependent manner. The release of histamine by TRA was also time dependent. On the other hand, high K+ (150 mM) strongly inhibited TRA-induced histamine release from rat mast cells. These results suggest that histamine release from mast cells might be associated with K+ channel activity.

Actomyosin↗
PubMed1992

Potent inhibitors of histamine release, two novel triterpenoids from the Okinawan marine sponge Penares incrustans.

Two novel triterpenoids with an unusual 14-carboxyl group, penasterone [1] and acetylpenasterol [2], were isolated from the Okinawan marine sponge Penares incrustans. The structures of 1 and 2 were established mainly on the basis of nmr spectroscopic data. The relative stereochemistry of 1 was confirmed by single-crystal X-ray diffraction analysis. Compounds 1 and 2 potently inhibited histamine release from rat peritoneal mast cells induced by anti-IgE in a dose-dependent manner.

Animals↗