Flavonol triglycosides from Blackstonia peroliata.

Three new flavonol triglycosides quercetin, kaempferol and isorhamnetin 3-rhamnosyl(1----2)galactoside-7-glucosides have been isolated from leaves and stems of Blackstonia perfoliata. This species together with three other genera of the tribe Gentianeae, subtribe Chlorae: Centaurium, Coutoubea and Eustoma, is unusual in producing flavonol glycosides instead of C-glycosyl flavones, the more characteristic flavonoid constituents of the Gentianaceae.     

Flavonol triglycosides from Magnolia utilis

Three undescribed flavonol triglycosides, rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-d-glucopyranoside (champaluangoside A), rhamnetin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-galactopyranoside (champaluangoside B) and rhamnocitrin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-glucopyranoside (champaluangoside C), were isolated from Magnolia utilis in addition to eleven known compounds; quercetrin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-glucopyranoside, oxytroflavoside G, magnoloside A, magnoloside M, magnoloside D, manglieside A, manglieside B, 1,2-di-O-β-d-glucopyranosyl-4-allylbebzene, syringrin, benzyl β-d-allopyranoside and (+)-syringaresinol-O-β-d-glucopyranoside. The structure elucidation of these compounds was based on analyses of physical and spectroscopic data.     

Flavonol triglycosides of leaves from Maytenus robusta with acetylcholinesterase inhibition

Although Maytenus robusta aqueous infusions of leaves are used in Brazilian traditional medicine for stomach disease treatment, only a few chemical studies of this species are found in literature. The phytochemical investigation of methanol extract from M. robusta leaves yielded the known compound kaempferol (3) and two new flavonol glycosides: kaempferol-3-O-β-d-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside (1) and quercetin-3-O-β-d-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside (2). The chemical structures of 1 and 2 were elucidated by 1D/2D NMR, ESI–MS and ESI–MS² spectral data. It is the first time flavonoids have been reported from M. robusta. Flavonols 1 and 2 showed 66% and 80% acetylcholinesterase (AChE) inhibition, compared to 93% of the standard eserine, by the Ellman’s method. These substances are one of the few active flavonols linked to a trisaccharide chain in the literature presenting this activity, and contribute to the screening for new types of natural AChE inhibitors.     

Microchemical assay of galactose containing cerebrosides

A method for the estimation of galactose containing lipids based on acid hydrolysis and fluorometric assay of galactose with galactose dehydrogenase has been developed. The characteristics of cerebroside hydrolysis under several different conditions are described. Under the conditions of hydrolysis sphingosine and galactose are released in parallel. A microchemical modification of the procedure has been used to assay galactose cerebroside-sulfatide in fragments of mouse cerebellar layers weighing 1–3 μg dry wt dissected from freeze-dried tissue sections.     

Effective diffusivity of galactose in calcium alginate gels containing immobilized Zymomonas mobilis.

The effective diffusivity of galactose was measured for calcium alginate gel membranes containing immobilized live Zymomonas mobilis cells at concentrations ranging from 0 to 150 g dry wt/L of gel. Since galactose is not taken up by living Z. mobilis organisms, the diffusion of this representative six-carbon sugar could be studied independently of sugar consumption. Various immobilized biomass loadings were achieved by two different techniques: addition of biomass at known concentrations to the sodium alginate solution before membrane formation and growth of cells in the gel to various biomass concentrations. The highest immobilized cell concentration, attained by in situ growth, corresponds to the maximum of this system, as growth beyond this maximum concentration led to disintegration of the gel membrane. The galactose effective diffusivity measurements for both methods of immobilized cell loading overlap within experimental error and follow the same general monotonic decline with entrapped biomass concentration. Most of the data fall below the upper bound predicted by Hashin and Shtrikman (1962) and show good agreement with the random pore model of Wakao and Smith (1962, 1964). Available effective diffusivity data from the literature provide evidence that the random pore model is an excellent predictor of sugar effective diffusivity in gel immobilized cell systems in general.     

Galactose oxidase action on galactose containing glycolipids--a fluorescence method

Features that alter the glycolipid sugar headgroup accessibility at the membrane interface have been studied in bilayer lipid model vesicles using a fluorescence technique with the enzyme galactose oxidase. The effects on oxidation caused by variation in the hydrophobic moiety of galactosylceramide or the membrane environment for galactosylceramide, monogalactosyldiacylglycerol and digalactosyldiacylglycerol were studied. For this study we combined the galactose oxidase method for determining the oxidizability of galactose containing glycolipids, and the fluorescence method for determining enzymatic hydrogen peroxide production. Exposed galactose residues with a free hydroxymethyl group at position 6 in the headgroup of glycolipids were oxidized with galactose oxidase and subsequently the resultant hydrogen peroxide was determined by a combination of horseradish peroxidase and 10-acetyl-3,7-dihydroxyphenoxazine (Amplex Red). Amplex Red reacts with hydrogen peroxide in the presence of horseradish peroxidase with a 1:1 stoichiometry to form resorufin. With this coupled enzyme approach it is also possible to determine the galactolipid transbilayer membrane distribution (inside-outside) in bilayer vesicles.     

Ricin antitoxins based on lyotropic mesophases containing galactose amphiphiles

Lyotropic mesophases of the inverse hexagonal or cubic type are nanostructured materials that result from the self-assembly of amphiphilic surfactant molecules in water. The extremely large area of the surfactant-water interface inherent within these structures makes them attractive media for sorbent or encapsulant systems. Here, we report on the development of a new class of polyvalent materials that are based on the incorporation of bioactive ligands within lyotropic mesophases. In particular, we have studied the potential for these materials to behave as polyvalent antitoxins by incorporating synthetic galactose amphiphiles, which mimic the natural cell surface ligand for the protein toxin ricin. The study demonstrates that cubic morphology lyotropic mesophases containing galactose amphiphiles exhibit high specificity ricin uptake, with favorably high dissociation constants and high capacities. We suggest that lyotropic mesophase polyvalent ligands are thus promising materials for the incorporation of a broad range of cell surface recognition moieties and hence may have wide applicability as materials capable of partaking in biological recognition processes.     

Flavonol diglycosides from Blackstonia perfoliata.

Two unusual diglycosides, quercetin and kaempferol 3-rhamnosyl(1----2)galactosides and the new isorhamnetin 3-rhamnosyl(1----2)galactoside have been isolated from the aerial parts of Blackstonia perfoliata. Instead of C-glycosylflavones, the occurrence of flavonol glycosides in this species as well as in three other genera of the Gentianaceae: Centaurium, Coutoubea and Eustoma, is in agreement with the grouping of these four genera in the subtribe Chlorae of the Gentianeae.     

Flavonol glycosides from Calotropis gigantea.

Besides isolation and characterization of isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucopyranoside and taraxasteryl acetate, a new flavonol trisaccharide was isolated from the aerial parts of Calotropis gigantea, and its structure was established as isorhamnetin-3-O-[2-O-beta-D-galactopyranosyl-6-O-alpha-L-rhamnopy ranosyl]- beta-D-glucopyranoside by a combination of fast atom bombardment mass spectroscopy, 1H and 13C NMR spectra and some chemical degradations.     

Flavonol glycosides from Monnina sylvatica.

A new kaempferol triglycoside and three known kaempferol glycosides, among them two apiosides, have been isolated from the aerial parts of Monnina sylvatica. The structures were established on the basis of acid and enzymatic hydrolysis and spectral data (UV, 1H and 13CNMR, NOE difference measurements, D/CI and FAB-MS) of the isolates and of some derivatives. The triglycoside kaempferol 3-O-beta-D-glucosyl-(1----2)-O-[alpha-L-rhamnosyl(1----6)]-beta-D- galactoside is a new natural product. The configuration of the apiosyl moiety in kaempferol 3-O-beta-D-apiosyl(1----2)-beta-D-galactoside and kaempferol 3-O-beta-D-apiosyl(1----2)-O-[alpha-L-rhamnosyl(1----6)]- beta-D-galactoside was established through NOE difference measurements on the peracetate.     

Structure of phosphonoglycosphingolipid containing pyruvylated galactose in nerve fibers of Aplysia kurodai

A phosphonoglycosphingolipid, designated as FGL-IIb, was identified in nerve fibers of Aplysia kurodai by two-dimensional thin layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). FGL-IIb was isolated from the nervous system of A. kurodai by Iatrobeads column chromatography using three solvent systems. Pyruvic acid was identified by thin layer chromatography as its 2,4-dinitrophenylhydrazone and established by permethylation studies to be attached as a ketal to O-3 and O-4 of the terminal galactose of the oligosaccharide chain in FGL-IIb. By sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structure of FGL-IIb was concluded to be [3,4-O-(1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3(Fuc alpha 1----2) (2-aminoethylphosphonyl----6)Gal beta 1----4Glc beta 1----1ceramide. Its major aliphatic components were palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. This is the first report of the occurrence of pyruvylated galactose as a constituent of animal sphingolipid.     

Studies of cocoa tea, a wild tea tree containing theobromine

Camellia ptilophylla Chang is a wild tea tree containing theobromine and is caffeine-flee. Lots of researches have been conducted for its domestication since it was discovered to contain theobromine in its shoots. First, its pharmacological and physiological effects have been studied, demonstrating that it can be used as a new resource of tea as daily and healthy beverage. Cocoa tea differs from traditional tea in that it does not excite the nervous system. Second, various ways of propagation have been investigated, and sexless cutting has been the method adopted currently. Third, through selection and breeding, plantation of cocoa tea can be set up to cultivate new varieties, and cocoa tea of different flavors such as green cocoa tea, oolong cocoa tea, and black cocoa tea can be processed. Thus, cocoa tea will become a choice in the tea market.     

Preparation of carcinoembryonic antigen (CEA) containing significantly increased amounts of galactose and galactosamine.

CEA was prepared by combined isoelectric precipitation, ultrafiltration and column chromatography under controlled conditions of pH. The resulting immunologically active materials were higher in carbohydrate (85-87%), N-acetyl galactosamine (10-11.5%) and galactose (28-32%) content than that previously reported. Differences in amino acid yield were also noted; the concentrations of aspartate, serine, glycine and alanine being higher and that of lysine, histidine, arginine, proline, valine, isoleucine, leucine and tyrosine were lower than that reported for CEA prepared by previous methods. The tumor tissues for CEA extraction were obtained from two Group O Rh positive deceased. Neither preparation showed Group A or B activity as measured by hemagglutination inhibition. It is suggested that the method of purification influences the carbohydrate and amino acid yields.     

Novel phosphonoglycosphingolipids containing pyruvylated galactose from the nervous system of Aplysia kurodai

We have reported the existence of a phosphonoglycosphingolipid containing a pyruvylated galactose, FGL-IIb, in nerve fibers of Aplysia kurodai (Araki, S., Abe, S., Ando, S., Kon, K., Fujiwara, N. & Satake, M. (1989) J. Biol. Chem. 264, 19922-19927). We have now isolated two other pyruvylated galactose-containing phosphonoglycosphingolipids, named FGL-V and FGL-IIa, from the nervous tissue of Aplysia, and characterized them as [3,4-O-(S-1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3[6'-O-(2- aminoethylphosphonyl)Gal alpha 1----2] (2-aminoethylphosphonyl----6) Gal beta 1----4Glc beta 1----1 ceramide and [3,4,O-(S-1-carboxyethylidene)] Gal beta 1----3GalNAc alpha 1----3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2]Gal beta 1----4Glc beta 11----ceramide, respectively. Their major aliphatic components are palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, the nervous system of Aplysia contains several pyruvylated phosphonoglycolipids.     

Flavonol and anthraquinone glycosides from Rhamnus formosana.

Two new flavonol triglycosides, and a new anthraquinone glycoside, have been isolated from the roots of Rhamnus formosana. These compounds have been characterized as rhamnazin 3-O-[alpha-L-rhamopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----6 )]-beta-D-galactopyranoside (rhamnazin 3-isorhamninoside), rhamnocitrin 3-O-isorhamninoside and 1,6,8-trihydroxy-3-methylanthraquinone 1-O-rhamnosyl(1----2)glucoside, respectively.     

Flavonol glycoside production in callus cultures of Epimedium diphyllum.

Callus cultures of Epimedium diphyllum produced a large amount of epimedoside A in addition to a small amount of diphylloside B, ikarisoside C, epimedoside E, diglycosides of des-O-methylanhydroicaritin (8-gamma, gamma-dimethylallylkaempfero). Icariin, epimedins A-C, which are glycosides of anhydroicaritin, were also produced in the callus cultures. Contents of the flavonol glycosides in callus tissue were higher than those of mother plants, but the composition of each flavonol glycoside mixture in the callus cultures was different from that of the original plants. The time-course experiments showed that an inverse relationship existed between cell growth and flavonol glycoside production. Effects of hormonal factors on cell growth and flavonol glycoside production indicated that 2,4-dichlorophenoxyacetic acid was needed for the production of flavonol glycosides.