Biomedical subjects
Publications and source records attributed to S Arihara.
A new bromopyrrole alkaloid (1) along with (+/-)-2 and (+/-)-longamide (3) has been isolated from the Japanese marine sponge Homaxinella sp. The structures of the compounds were proposed on the basis of spectroscopic data. The optical resolution of (+/-)-2 by chiral HPLC was successful and afforded the two enantiomers, (+)-2 and (-)-2.
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.
The structural elucidation of six new related polyoxypregnane glycosides, gymnepregosides A (1), B (2), C (3), D (4), E (5) and F (6), together with two known compounds, from the roots of Gymnema alternifolium (Asclepiadaceae) was achieved through on a detailed study of 1H- and 13C-NMR spectral data and chemical means. The results obtained for new compounds, 1-6, show that they are (20S)-pregn-6-ene-3 beta,5 alpha,8 beta,12 beta,14 beta,17 beta,20-heptaol or sarcostin 3-O-glycosides, and all the sugars at C-3 are beta(1-->4)-linked. Some of them possessed benzoyl, cinnamoyl and tigloyl residues as the ester linkages located at C-12 and/or C-20 of the aglycon.
Seven saponins named pithedulosides A-G were isolated from the seeds of Pithecellobium dulce. Their structures were established through spectral analyses as echinocystic acid 3-O-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside, echinocystic acid and oleanolic acid 3-O-alpha-L-arabinopyranosyl- (1-->2)-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranosides and 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl -(1-->6)-beta-D-glucopyranosides, oleanolic acid 3-O-alpha-L-arabinopyranosy-(1-->2)-alpha-L- arabinopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1-->2)]-beta- D-glucopyranoside, and 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6) -[beta-D-glucopyranosyl-(1-->2)]--beta-D-glucopyranoside.
Four new oleanane-type triterpene glycosides, pithedulosides H-K (1-4), were isolated from the seeds of Pithecellobium dulce. Their structures were established by extensive NMR experiments and chemical methods. Compounds 1-3 comprised acacic acid as the aglycon and either monoterpene carboxylic acid and its xyloside or monoterpene carboxylic acid as the acyl moiety at C-21. The oligosaccharide moieties linked to C-3 and C-28 were determined as alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1 -->6)- [beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosyl and alpha-L-arabinofuranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->3)]-alpha- rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester, respectively. Compound 4 was established as an echinocystic acid 3-O-glycoside having the same sugar sequences as 1-3. Also obtained in this investigation was the known compound 5, which was identified as echinocystic acid 3-O-beta-D-xylopyranosyl- (1-->2)-alpha-L-arabinopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1 -->2)]- beta-D-glucopyranoside.
From the fresh stem of Stephanotis lutchuensis var. japonica, ten new oleanane-type triterpenoid glycosides, named sitakisosides XI-XX (1-10), were isolated. Their structures were determined on the basis of spectroscopic data and chemical evidence. The results show that all have a 3-O-beta-D-xylopyranosyl(1 --> 6)-beta-D-glucopyranosyl(1 --> 6)- beta-D-glucopyranosyl moiety and the aglycones of sitakisosides XI-XV, XVI and XVII, XVIII and XIX, and XX are sitakisogenin, chichipegenin, marsglobiferin and longispinogenin, respectively. Sitakisosides XI-XIII, XVI and XVIII, having an acyl group, showed antisweet activity.
The structural elucidation of seven related oxypregnane-oligoglycosides stephanosides K (1), L (2), M (3), N (4), O (5), P (6), and Q (7) from the fresh stem of Stephanotis lutchuensis var. japonica (Asclepiadaceae) was achieved through on a detailed study of their high-field 1H- and 13C-NMR spectra. The results show that all the sugars are beta (1-->4)-linked. The aglycones of stephanosides K, M, and O, and stephanosides L, N, and P were identified as 12-O-cinnamoyl-20-O-(E)-2-methyl-2-butenoyl, and 12-O-cinnamoyl-20-O-nicotinoyl derivatives of (20S)-pregn-6-ene-3 beta,5 alpha,8 beta,12 beta,14 beta,17 beta,20-heptaol, respectively. The aglycone of stephanoside Q was 12-O-cinnamoyldeacetylmetaplexigenin (kidjoranin).
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.
Three main saponins named albiziasaponins A, B, and C were isolated from the barks of Albizia lebbeck. Their structures were established through spectral analyses as acacic acid lactone 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)- beta-D-glucopyranoside, 3-O-beta-D-glucopyranosyl-(1-->2)-O-[alpha-L-arabinopyranosyl-(1-- >6)]- beta-D-glucopyranoside and 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)- O- [beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranoside.
Three monodesmosidic glucuronide saponins of barringtogenol C, named barringtosides A, B and C have been isolated as their methyl esters from the dried seeds of Barringtonia acutangula. On the basis of chemical and spectral evidence, the structures of these new saponins were elucidated to be as follows: barringtoside A, 3-O-beta-D-xylopyranosyl(1-->3)-[beta-D-galactopyranosyl(1-->2)]-beta-D- glucuronopyranosyl barringtogenol C; barringtoside B, 3-O-beta-D-xylopyranosyl(1-->3)-]beta-D-galactopyranosyl(1-->2)]-beta-D- glucuronopyranosyl-21-O-tigloyl-28-O-isobutyryl barringtogenol C; barringtoside C, 3-O-alpha-L-arabinopyranosyl(1-->3)-[beta-D-galactopyranosyl(1-->2 )]-beta-D - glucuronopyranosyl barringtogenol C.
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.
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.
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.
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.
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.
From the fresh stem of Stephanotis lutchuensis var. japonica, we have isolated five new oleane glycosides named sitakisosides I-V (1-5). Their structures were determined on the basis of spectroscopic data and chemical evidence. Sitakisoside V showed the strongest antisweet activity among sitakisosides I-V.
From the fresh stem of Stephanotis lutchuensis var. japonica, five new oleanane-type triterpenoid glycosides named sitakisosides VI-X (1-5) were isolated. Their structures were determined on the basis of spectroscopic data and chemical evidence. Sitakisosides VI and VII are 3-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranosyl(1-->6)-beta-D- glucopyranosido-21-O-(6-N-methylanthranilyl)-beta-D-glucopyr anosyl and 3-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranosyl(1-->6)-beta-D- glucopyranosido-21-O-(4-N-methylanthranilyl)-beta-D-glucopyr anosyl sitakisogenin, respectively. Sitakisoside VIII is 3-O-beta-D-xylopyranosyl(1-->6)-beta-D- glucopyranosyl(1-->6)-beta-D-glucopyranosido-21-O-N-methylanthr anilyl- 3 beta,16 beta,21 beta,28-tetrahydroxyolean-12-ene-22-one. Sitakisoside IX is 3-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranosyl(1-->6)-beta-D- glucopyranosido-21-O-(6-N-methylanthranilyl)-beta-D-glucopyr anosyl gymnestrogenin. Sitakisoside X is 3-O-beta-D-xylopyranosyl(1-->6)-beta-D- glucopyranosyl(1-->6)-beta-D-glucopyranosyl longispinogenin.
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.