Triterpenoid saponins and phenylethanoid glycosides from stem of Akebia trifoliata var. australis

A detailed phytochemical study on the 70% aqueous ethanol extract of stems of Akebia trifoliata (Thunb.) Koidz. var. australis (Diels) Rehd led to isolation of five compounds, together with 12 known triterpenoid saponins and three known phenylethanoid glycosides. The structures of the five compounds were elucidated on the basis of analysis of spectroscopic data and physicochemical properties as: 2alpha, 3beta, 23-trihydroxy-30-norolean-12-en-28-oic acid beta-D-glucopyranosyl ester (1), 2alpha, 3beta, 23-trihydroxy-30-norolean-12-en-28-oic acid beta-D-xylopyranosyl-(1-->3)-O-alpha-D-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (2), 2alpha, 3beta, 23-trihydroxyurs-12-en-28-oic acid beta-D-xylopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (3), 3-beta-[(beta-D-glucopyranosyl-(1-->3)-O-alpha-L-arabinopyranosyl)oxy]-23-hydroxy-30-norolean-12-en-28-oic acid alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (4) and 3-beta-[(alpha-L-xylopyranosyl-(1-->2)-O-alpha-L-arabinopyranosyl)oxy]-30-norolean-12-en-28-oic acid alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->6)-O-beta-D-glucopyranosyl ester (5), named mutongsaponin A, B, C, D and E, respectively.     

Saponins from Allium minutiflorum with antifungal activity

Three saponins, named minutoside A (1), minutoside B (2), minutoside C (3), and two known sapogenins, alliogenin and neoagigenin, were isolated from the bulbs of Allium minutiflorum Regel. Elucidation of their structure was carried out by comprehensive spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry. The structures of the new compounds were identified as (25R)-furost-2alpha,3beta,6beta,22alpha,26-pentaol 3-O-[beta-D-xylopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-galactopyranosyl] 26-O-beta-D-glucopyranoside (1), (25S)-spirostan-2alpha,3beta,6beta-triol 3-O-beta-D-xylopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-galactopyranoside (2), and (25R)-furost-2alpha,3beta,5alpha,6beta,22alpha,26-esaol 3-O-[beta-D-xylopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-galactopyranosyl] 26-O-beta-D-glucopyranoside (3). The isolated compounds were evaluated for their antimicrobial activity. All the novel saponins showed a significant antifungal activity depending on their concentration and with the following rank: minutoside B>minutoside C>minutoside A. No appreciable antibacterial activity was recorded. The possible role of these saponins in plant-microbe interactions is discussed.     

Cytotoxic triterpenoid saponins from the fruits of Aesculus pavia L

Continued chemical investigation on the fruits of North American Aesculus pavia L. resulted in the isolation and identification of 13 polyhydroxyoleanene pentacyclic triterpenoid saponins, named aesculiosides IIe-IIk (1-7), and IIIa-IIIf (8-13), together with 18 known compounds: aesculiosides Ia-Ie (14-18), IIa-IId (19-22), IVa-IVc (23-25), 3-O-[beta-D-galactopyranosyl(1-->2)]-alpha-L-arabinofuranosyl(1-->3)-beta-D-glucuronopyranosyl-21,22-O-diangeloyl-3beta,15 alpha,16 alpha,21 beta,22 alpha,28-hexahydroxyolean-12-ene (26), 3-O-[beta-D-glucopyranosyl(1-->2)]-alpha-L-arabinofuranosyl(1-->3)-beta-D-glucuronopyranosyl-21,22-O-diangeloyl-3beta,16 alpha,21 beta,22 alpha,24 beta,28-hexahydroxyolean-12-ene (27), 3-O-[beta-D-galactopyranosyl(1-->2)]-alpha-L-arabinofuranosyl(1-->3)-beta-D-glucuronopyranosyl-21,22-O-diangeloyl-3beta,16 alpha,21 beta,22 alpha,28-pentahydroxyolean-12-ene (28), R(1)-barrigenol (29), scopolin (30), and 5-methoxyscopolin (31). The structures of these compounds were elucidated by spectroscopic and chemical analyses. Compounds 14-22 and 26-28 were tested in vitro for their activity against 59 cell lines from nine different human cancers including leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast. It was found that compounds with two-acyl groups at C-21 and C-22 had cytotoxic activity for all cell lines tested with GI(50) 0.175-8.71 microM, while compounds without acyl groups at C-21 and C-22 had weak or no cytotoxic activity. These results suggest that the acyl groups at C-21 and C-22 are essential for their activity.     

Development of a 1H NMR structural-reporter-group concept for the primary structural characterisation of alpha-D-glucans

An NMR study of proton chemical shift patterns of known linear alpha-D-glucopyranose di- and trisaccharide structures was carried out. Chemical shift patterns for (alpha1-->2)-, (alpha1-->3)-, (alpha1-->4)- and (alpha1-->6)-linked D-glucose residues were analysed and compared to literature data. Using these data, a 1H NMR structural-reporter-group concept was formulated to function as a tool in the structural analysis of alpha-D-glucans.     

Triterpene saponins and iridoid glucosides from galium rivale

Three new glycosides of the oleanene-type triterpenes, rivalosides C-E (1-3), along with three known triterpene saponins, momordin IIb (4) and rivalosides A-B (5-6), and five known iridoid glucosides: monotropein, scandoside, deacetylasperulosidic acid, geniposidic acid and asperulosidic acid, were isolated from aerial parts of Galium rivale. The structures of the new compounds were elucidated by spectral methods and chemical means as 2alpha-acetoxy-3alpha, 19alpha-dihydroxy-olean-12-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1--> 6)-beta-D-glucopyranoside, 2alpha,3alpha, 19alpha-trihydroxy-olean- 12-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranoside and 3-O-beta-D-glucuronopyranosyl-24-hydroxy-olean-12-en-28-oic acid 28-O-beta-D-glucopyranoside, for rivalosides C-E, respectively. The taxonomic significance of the rivalosides in G. rivale was discussed.     

Saikosaponins from roots of Bupleurum gibraltaricum and Bupleurum spinosum

Two new saikosaponins have been identified in the butanolic fraction of the ethanol extract of the roots of Bupleurum spinosum: 3beta,16alpha,23,28-tetrahydroxyoleana-11,13(18)-dien- 30-oic acid 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-fucopyranoside, and 3beta,16alpha,23,28,30-pentahydroxyoleana-11,13(18)-diene 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-fucopyranoside. 3Beta,16beta,23-trihydroxy-13,28-epoxyolean-11-ene 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-fucopyranoside was also isolated, and this structure agreed with the one proposed for bupleuroside I, but their spectroscopic data have not been described until now. From the same fraction of the roots of Bupleurum gibraltaricum, the known compound buddlejasaponin IV has been isolated as the predominant component (90%). Structures were elucidated using spectroscopic analysis, specially 2D-NMR experiments.     

Leishmanicidal cycloartane-type triterpene glycosides from Astragalus oleifolius

Two new cycloartane-type glycosides oleifoliosides A (1) and B (2) were isolated from the lower stem parts of Astragalus oleifolius. Their structures were identified as 3-O-[beta-xylopyranosyl-(1 --> 2)-alpha-arabinopyranosyl]-6-O-beta-xylopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane and 3-O-[beta-xylopyranosyl-(1 --> 2)-alpha-arabinopyranosyl]-6-O-beta-glucopyranosyl-3beta,6alpha,16beta,24(S),25-pentahydroxycycloartane, respectively, by means of spectroscopic methods (IR, 1D and 2D NMR, ESI-MS). Three known cycloartane glycosides cyclocanthoside E (3), astragaloside II (4) and astragaloside IV (5) were also isolated and characterized. All five compounds were evaluated for in vitro trypanocidal, leishmanicidal and antiplasmodial activities as well as their cytotoxic potential on primary mammalian (L6) cells. Except for the compound 5, all compounds showed notable growth inhibitory activity against Leishmania donovani with IC50 values ranging from 13.2 to 21.3 microg/ml. Only weak activity against Trypanosoma brucei rhodesiense was observed with the known compounds astragaloside II (4, IC50 66.6 microg/ml) and cyclocanthoside E (3, IC50 85.2 microg/ml), while all compounds were inactive against Trypanosoma cruzi and Plasmodium falciparum. None of the compounds were toxic to mammalian cells (IC50's > 90 microg/ml). This is the first report of leishmanicidal and trypanocidal activity of cycloartane-type triterpene glycosides.     

ent-Kaurenoic acids from Mikania hirsutissima (Compositae)

Four ent-kaurenoic acid derivatives, 2beta,16alpha,17-trihydroxy-ent-kauran-19-oic acid (1), 3beta,16alpha,17-trihydroxy-ent-kauran-19-oic acid (2), 11alpha,15beta-dihydroxy-7-O-beta-d-glucopyranosyl-ent-kaur-16-en-19-oic acid (3) and 1alpha,15beta-dihydroxy-7-O-beta-d-glucopyranosyl-ent-kaur-16-en-19-oic acid (4), were isolated together with five known compounds, 1,5-dicaffeoyl-quinic acid (5), 2-O-glucosyloxy-4-methoxy-cinnamic acid (6), phenethyl alcohol glucoside (7), phenethyl-1-O-beta-d-apiofuranosyl (1-->2) beta-d-glucopyranoside (sayaendoside) (8) and 3,6-dihydroxy-beta-ion-9-ol (9) from the 50% aqueous acetone extract of the aerial parts of Mikania hirsutissima DC. (Compositae). Compounds 1-9 were tested for their proliferative activity toward peripheral blood mononuclear cells (hPBMC); compounds 1 and 2 showed significant activity (43.8% and 36.7%, at 100 microM, respectively) on the lymphocyte.     

Effect of synthetic sialyl 2-->1 sphingosine and other glycosylsphingosines on the structure and function of the "glycosphingolipid signaling domain (GSD)" in mouse melanoma B16 cells

Mouse melanoma B16 cells are characterized by a high concentration of GM3 ganglioside, which has been identified as a melanoma-associated antigen and is present as a clustered microdomain organized with major signal transducers, c-Src, small G-protein (Rho A), and focal adhesion kinase (FAK), to form a "glycosphingolipid signaling domain" or "glycosignaling domain" (GSD) separable from cholesterol- and caveolin-enriched microdomain, "caveolae." Cholesterol-binding reagents, filipin and nystatin, disrupt the structure and function of caveolae, but have no effect on GSD function [Iwabuchi, K., et al. (1998) J. Biol. Chem. 273, 33766-33773]. In this study, we searched for compounds which disrupt the structure and function of GSD in B16 cells. Such compounds should have structural features analogous to those of GM3, destroy or reduce clustering of GM3 in GSD, and inhibit GM3-dependent adhesion and signaling. The simplest compound so far found with these properties is sialyl alpha2-->1 sphingosine (Sph). We describe the synthesis of this compound and its analogues, and their effects on GM3 expression pattern and GSD function, in comparison with effects of lyso-GM3 and other lyso compounds, in B16 cells. Incubation of B16 cells with 0.5-10 microM sialyl alpha2-->1 Sph or 1-5 microM lyso-GM3 reduced GM3 clustering and GM3-dependent adhesion, and inhibited adhesion-dependent cellular FAK activity. The c-Src activation response of GSD isolated from B16 cells was inhibited strongly by sialyl alpha2-->1 Sph. Substitution of the Sph amino group with a chloroacetyl or N,N-dimethyl group strongly reduced the inhibitory effect of sialyl alpha2-->1 Sph on GM3-dependent adhesion, FAK, and c-Src response. Other lyso compounds such as lyso-phosphatidylcholine, galactosyl-Sph (psychosine), and lactosyl-Sph at 0.5-10 microM did not show the same effect as sialyl alpha2-->1 Sph. Thus, adhesion coupled with signal transduction, initiated by clusters of GM3 in GSD, is blocked by sialyl alpha2-->1 Sph or lyso-GM3. Analogues with N-substitution of Sph in sialyl alpha2-->1 Sph, other lyso-phospholipids, and galactosyl- or lactosyl-Sph did not block such adhesion, coupled with activation of c-Src and FAK.     

Hopane-type saponins from Glinus lotoides Linn

Seven hopane-type saponins were isolated from the methanol extract of Glinus lotoides. Six of them were identified as novel compounds and designated as lotoideside A [3-O-beta-D-xylopyranosyl (1-->2)-alpha-L-rhamnopyranosyl-6 alpha-O-beta-D-xylopyranosyl-22-beta-O-beta-D-glucopyranosyl-16 beta-hydroxy hopane (1)], lotoideside B [3-O-beta-D-xylopyranosyl (1-->2)-alpha-L-rhamnopyranosyl-22-beta-O-beta-D-glucopyranosyl-6 alpha,16 beta-dihydroxyhopane (2)], lotoideside C [3-OD-xylopyranosyl-6 alpha-O-beta-D-xylopyranosyl-16 beta-O-beta-D-xylopyranosyl-22 beta-hydroxyhopane (3)], lotoideside D [3-O-beta-D-xylopyranosyl-16 beta-O-alpha-L-arabinopyranosyl-6 alpha,22-beta-dihydroxyhopane (4)], lotoideside E [3-O-beta-D-xylopyranosyl-6 alpha-O-beta-D-xylopyranosyl-16 beta,22-beta-dihydroxyhopane (5)], and lotoideside F [3-O-beta-D-xylopyranosyl-22-beta-O-beta-D-glucopyranosyl-16 beta-hydroxyhopan-6-one (6)]. The known compound succulentoside B (7) was also encountered. Their structures were elucidated on the basis of one-and two-dimensional NMR spectroscopic techniques, ESIMS and chemical evidences.     

Triterpenoidal lupin saponins from the Chilean legume Lupinus oreophilus Phil

Two lupin saponins, 3beta,21alpha,22beta,24-tetrahydroxyolean-12-en-3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-O-alpha-L-arabinopyranoside and 3beta,21alpha,22beta,24-tetrahydroxyolean-12-en-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-O-alpha-L-rhamnopyranoside, along with eight other saponins and one triterpene previously reported from other legumes, were isolated from the aerial parts of Lupinus oreophilus collected in northern Chile. The structures of the isolated compounds were established with the help of extensive spectroscopic techniques.     

A triterpenoidal saponin and sphingolipids from Pteleopsis hylodendron

From the stem bark of Pteleopsis hylodendron, a triterpenoidal saponin bellericagenin [B 3-O-[beta-D-glucopyranosyl-(1-->2)-alpha-D-glucopyranoside] (1) (Pteleopsoside)] and two sphingolipids, hylodendroside-I (2), and hylodendroside-II (3) were isolated, along with a synthetically known compound, [2alpha, 3beta, 23-triacetoxy-19alpha-hydroxyolean-12-en-28-oic acid (4)]. Other known compounds, friedelin (5), beta-carotene (6), lupeol (7), sitosterol (8), and stigmasterol (9), were also obtained. Their structures were deduced with the help of detailed spectroscopic studies.     

Secondary metabolites from Senecio burtonii (Compositae)

A cacalolide derivative named 4alpha-[2'-hydroxymethylacryloxy]-1beta-hydroxy-14-(5-->6) abeo eremophilan-12,8-olide and a shikimic acid derivative named (3'E)-(1alpha)-3-hydroxymethyl-4beta,5alpha-dimethoxycyclohex-2-enyloctadec-3'-enoate along with three known compounds, octacosan-1-ol, 3beta-hydroxyolean-12-en-28-oic acid and 3beta-acetoxyolean-12-en-28-oic acid were isolated from Senecio burtonii. Their structures and relative configurations were established on the basis of spectroscopic analysis.     

New steroid glycosides from the starfish Fromia milleporella

Two new steroid glycosides from the starfish Fromia milleporella collected in the Seychelles were isolated and characterized: milleporoside A, (20R, 24R)-29-O-[3-O-methyl-beta-D-xylopyranosyl-(1-->4)-3-O-methyl-beta-D-xylopyranosyl]-24-ethyl-5alpha-cholestane-3beta,4beta,6alpha,8,15beta,16beta,29-heptaol, and milleporoside B, (20R, 24R)-(22E)-28-O-[3-O-methyl-beta-D-xylopyranosyl-(1-->4)-3-O-methyl-beta-D-xylopyranosyl]-24-methyl-5alpha-cholest-22-ene-3beta,4beta,6alpha,8,15beta,16beta,28-heptaol. The structures of the glycosides were determined from their spectra and a comparison with spectral characteristics of known compounds. These compounds exhibit a moderate cytostatic activity toward the embryos of the sea urchin Strongylocentrotus intermedius.     

Defects in degradation of blood group A and B glycosphingolipids in Schindler and Fabry diseases

Skin fibroblast cultures from patients with inherited lysosomal enzymopathies, alpha-N-acetylgalactosaminidase (alpha-NAGA) and alpha-galactosidase A deficiencies (Schindler and Fabry disease, respectively), and from normal controls were used to study in situ degradation of blood group A and B glycosphingolipids. Glycosphingolipids A-6-2 (GalNAc (alpha 1-->3)[Fuc alpha 1-->2]Gal(beta1-->4)GlcNAc(beta 1-->3)Gal(beta 1--> 4)Glc (beta 1-->1')Cer, IV(2)-alpha-fucosyl-IV(3)-alpha-N-acetylgalactosaminylneolactotetraosylceramide), B-6-2 (Gal(alpha 1-->3)[Fuc alpha 1--> 2] Gal (beta 1-->4)GlcNAc(beta 1-->3)Gal(beta 1-->4)Glc(beta 1-->1')Cer, IV(2)- alpha-fucosyl-IV(3)-alpha-galactosylneolactotetraosylceramide), and globoside (GalNAc(beta 1-->3)Gal(alpha 1-->4)Gal(beta 1-->4)Glc(beta 1-->1') Cer, globotetraosylceramide) were tritium labeled in their ceramide moiety and used as natural substrates. The degradation rate of glycolipid A-6-2 was very low in fibroblasts of all the alpha-NAGA-deficient patients (less than 7% of controls), despite very heterogeneous clinical pictures, ruling out different residual enzyme activities as an explanation for the clinical heterogeneity. Strongly elevated urinary excretion of blood group A glycolipids was detected in one patient with blood group A, secretor status (five times higher than upper limit of controls), in support of the notion that blood group A-active glycolipids may contribute as storage compounds in blood group A patients. When glycolipid B-6-2 was fed to alpha-galactosidase A-deficient cells, the degradation rate was surprisingly high (50% of controls), while that of globotriaosylceramide was reduced to less than 15% of control average, presumably reflecting differences in the lysosomal enzymology of polar glycolipids versus less-polar ones. Relatively high-degree degradation of substrates with alpha-D-Galactosyl moieties hints at a possible contribution of other enzymes.     

Acylated apigenin glycosides from alfalfa (Medicago sativa L.) var. Artal.

Three flavones, including 4'-O-[2'-O-E-feruloyl-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]apigenin, 7-O-beta-D-glucuronopyranosyl-4'-O-[2'-O-E-feruloyl-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]apigenin and 7-O-beta-D-glucuronopyranosyl-4'-O-[2'-O-p-E-coumaroyl-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucuronopyranoside]apigenin have been identified in alfalfa var. Artal. The known flavone 7-O-[2-O-E-feruloyl-[beta-D-glucuronopyranosyl(1-->3)]-O-beta-D-glucuronopyranosyl(1-->2)-O-beta-D-glucurono-pyranoside] apigenin was also isolated. The structures of these compounds were deduced on the basis of their spectral data.     

Triterpenoid glycosides from Bacopa monnieri

Two triterpenoid glycosides have been isolated along with 10 known saponins from Bacopa monnieri. Structures of the compounds have been elucidated as 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl] jujubogenin (1) and 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl] pseudojujubogenin (2) by high resolution NMR spectral data and chemical correlations. Further, the chemical compositions of bacosides A and B have been delineated.     

Analysis of glycosylinositol phosphorylceramides expressed by the opportunistic mycopathogen Aspergillus fumigatus

Acidic glycosphingolipid components were extracted from the opportunistic mycopathogen Aspergillus fumigatus and identified as inositol phosphorylceramide and glycosylinositol phosphorylceramides (GIPCs). Using nuclear magnetic resonance sppectroscopy, mass spectrometry, and other techniques, the structures of six major components were elucidated as Ins-P-Cer (Af-0), Manp(alpha1-->3)Manp(alpha1-->2)Ins-P-Cer (Af-2), Manp(alpha1-->2)Manp(alpha1-->3)Manp(alpha1-->2)Ins-P-Cer (Af-3a), Manp(alpha1-->3)[Galf(beta1-->6)]Manp(alpha1-->2)-Ins-P-Cer (Af-3b), Manp(alpha1-->2)-Manp(alpha1-->3)[Galf(beta1-->6)]Manp(alpha1-->2)Ins-P-Cer (Af-4), and Manp(alpha1-->3)Manp(alpha1-->6)GlcpN(alpha1-->2)Ins-P-Cer (Af-3c) (where Ins = myo-inositol and P = phosphodiester). A minor A. fumigatus GIPC was also identified as the N-acetylated version of Af-3c (Af-3c*), which suggests that formation of the GlcNalpha1-->2Ins linkage may proceed by a two-step process, similar to the GlcNalpha1-->6Ins linkage in glycosylphosphatidylinositol (GPI) anchors (transfer of GlcNAc, followed by enzymatic de-N-acetylation). The glycosylinositol of Af-3b, which bears a distinctive branching Galf(beta1-->6) residue, is identical to that of a GIPC isolated previously from the dimorphic mycopathogen Paracoccidioides brasiliensis (designated Pb-3), but components Af-3a and Af-4 have novel structures. Overlay immunostaining of A. fumigatus GIPCs separated on thin-layer chromatograms was used to assess their reactivity against sera from a patient with aspergillosis and against a murine monoclonal antibody (MEST-1) shown previously to react with the Galf(beta1-->6) residue in Pb-3. These results are discussed in relation to pathogenicity and potential approaches to the immunodiagnosis of A. fumigatus.     

Bioactive sucrose esters from Bidens parviflora

An investigation on Bidens parviflora led to the isolation of three sucrose esters and a substituted truxillate. Their structures were elucidated as (6-O-(E)-p-coumaroyl)-beta-D-fructofuranosyl-(2-->1)-alpha-D-glucopyranoside, (6-O-(E)-p-coumaroyl)-beta-D-fructofuranosyl-(2-->1)-(6-O-(E)-p-coumaroyl)-alpha-D-glucopyranoside II, 6,6'-sucrose ester of (1alpha,2alpha,3beta,4beta)-3,4-bis(4-hydroxyphenyl)-1,2-cyclobutanedicarboxylic acid, dimethyl ester of (1alpha,2alpha,3alpha,4alpha)-2,4-bis(3,4-dihydroxyphenyl)-1,3-cyclobutanedicarboxylic acid on the basis of spectral and chemical evidence. These compounds were subjected to the following bioassays: the histamine release inhibition of rat mast cells induced by antigen-antibody reaction and the inhibitory activity of PGE(2) production by macrophages.     

Glycolipids from Thermotoga maritima, a hyperthermophilic microorganism belonging to Bacteria domain.

Two novel glycolipids with a very rare alpha(1-->4) diglucosyl structure have been isolated from the thermophilic bacterium Thermotoga maritima. The structures of these compounds, on the basis of chemical procedures and spectroscopic studies (FAB-MS and NMR), were shown to be: 1(3),2-dipalmitoyl-3(1)-[glucopyranosyl-(6-decanoyl)-alpha-D-(1-->4)- glucopyranosyl-alpha-D]-glycerol (Glycolipid 1) and 1(3),2-dipalmitoyl-3(1)-[glucopyranosyl-alpha-D-(1-->4)-glucopyranosyl- alpha-D]-glycerol (Glycolipid 2).