Hepatoprotective Constituents of Macrocybe gigantea (Agaricomycetes) from India.

Non-alcoholic fatty liver disease (NAFLD) is one of the most frequent, chronic liver diseases worldwide and currently has no specific therapy. Our previous study indicated the anti-NAFLD effect of Macrocybe gigantea (Massee) Pegler & Lodge in high-fat diet-fed animals. This study aimed to isolate and identify the active hepatoprotective constituents from M. gigantea using fatty acid induced steatotic HepG2 cells as in vitro model. The effect of the test materials on the viability of HepG2 cells was analyzed using MTT assay. The HepG2 cells were treated with a mixture of palmitate-oleate to induce steatosis; after 24 h of treatment with the test materials, the intracellular lipid content was estimated using Oil Red O staining. The levels of transaminases were also estimated in the spent media. Bioassay-guided isolation of hepatoprotective constituents from M. gigantea yielded two compounds viz., ergosterol and linoleic acid; their structures were confirmed using spectroscopic data. Among these two compounds, ergosterol significantly lowered the levels of intracellular triglyceride content of fatty acid induced HepG2 cells; it also lowered the leakage of transaminases. The reductions caused by linoleic acid were not statistically significant at the tested concentrations. Detailed investigations on efficacy and safety of these compounds and M. gigantea might yield some useful leads for the management of NAFLD.

Direct determination of bisphenol A and nonylphenol in river water by column-switching semi-microcolumn liquid chromatography/electrospray mass spectrometry

A rapid and sensitive analytical method based on column-switching semi-microcolumn high-performance liquid chromatography (HPLC) with electrospray mass spectrometry was developed for determining trace levels of bisphenol A (2,2-bis(4-hydroxyphenyl)propane) and nonylphenol (4-nonylphenol) in river water. An aliquot of sample solution was directly injected into the precolumn packed with Capcellpak MF-Ph for sample cleanup and enrichment. The compounds of interest were then transferred to a C-18 analytical column for main separation through a change in flow path by a programmed switching valve. Bisphenol A, nonylphenol, and interfering substances were satisfactorily separated with a simple gradient elution complete within 35 min. Detection of their deprotonated molecules was conducted in negative ion mode. A reduced flow rate (100 &mgr;L/min) optimized for the narrow bore column was found advantageous in obtaining a high degree of sensitivity during electrospray detection. The influence of carrier additives on sensitivity was also examined. This method produced detection limits of 0.5 ng/mL for bisphenol A and 10 ng/mL for nonylphenol (signal-to-noise ratio 3). Calibration curves were observed in the range of 2.5-50 ng/mL (r(2) = 0.999) for bisphenol A and 50-500 ng/mL (r(2) = 0.998) for nonylphenol. Recoveries of the compounds from spiked distilled water and river water were 99.7-138.5% with a relative standard deviation (RSD) ranging from 2.2-9.7%. Copyright 1999 John Wiley & Sons, Ltd.

Direct determination of methamphetamine enantiomers in urine by liquid chromatography with a strong cation-exchange precolumn and phenyl-beta-cyclodextrin-bonded semi-microcolumn.

Methamphetamine enantiomers in drug abusers' urine were clearly separated by semi-microcolumn liquid chromatography using a column-switching system. The system consists of two separation processes: firstly, a strong cation-exchange precolumn removes neutral and anionic substances in urine, and then methamphetamine enantiomers trapped in the column are transferred to and separated in a phenyl-beta-cyclodextrin-bonded semi-microcolumn (Chiral Drug, 150 mm x 1.5 mm I.D.). (S)-(+)-Methamphetamine was baseline separated from (R)-(-)-methamphetamine within 25 min, directly from urine samples. The detection limit for both enantiomers was 0.1 microg/ml.

Triterpenoid saponin from Vaccaria segetalis.

A new triterpenoid saponin, vaccaroid B, has been isolated from the seeds of Vaccaria segetalis and its structure was elucidated to be 3beta-hydroxyolean-12-en-23, 28-dioic acid-28-O-beta-D-glucopyranosyl-(1-->3)- beta-D-glucopyranosyl-(1-->6)-[6- O-(3-hydroxy-3-methylglutaryl)-beta-D-glucopyranosyl-(1-->2)]- beta-D-glucopyranoside by spectroscopic methods.

Antiandrogenic natural Diels--Alder-type adducts from Brosimum rubescens.

The isolation and structure elucidation of five novel natural Diels--Alder-type adducts, named palodesangrens A-E (1-5), from the Peruvian folk medicine known as "palo de sangre" (Brosimum rubescens) is described. The structures of the Diels--Alder adducts, consisting of chalcone derivatives and a prenylcoumarin, were elucidated by analysis of spectroscopic data including 2D NMR. Some of these compounds showed potent inhibitory activity towards 5 alpha-dihydrotestosterone (DHT) binding with an androgen receptor to form a DHT-receptor complex that causes androgen-dependent diseases.

Analysis of ibuprofen metabolites by semi-microcolumn liquid chromatography with ultraviolet absorption and pulsed amperometric detectors.

Semi-microcolumn (1.5 mm i.d.) liquid chromatography (LC) system with ultraviolet (UV) and pulsed amperometric detector (PAD) was constructed for analysis of ibuprofen metabolites in human urine. PAD was connected in series with the UV detector, and an alkaline solution was post-column added to a mobile phase after the UV detector. By a gradient elution, five ibuprofen metabolites were detected with UV detection from 1 microliter of human urine at 3.5 h after the administration, and information concerning their glucuronation was simultaneously obtained by PAD response.

Thionation of segetalins A and B, cyclic peptides with estrogen-like activity from seeds of Vaccaria segetalis.

Thionation of estrogen-like active cyclic peptides, segetalins A (1) and B (2), with Lawesson's reagent provided each two thiosegetalins; thiosegetalin A1 [Gly-1-psi(CS-NH)-Val-2; Trp-5-psi (CS-NH)-Ala-6]segetalin A, thiosegetalin A2 [Gly-1-psi(CS-NH)-Val-2; Ala-6-psi(CS-NH)-Gly-1]segetalin A, thiosegetalin B1 [Gly-1-psi (CS-NH)-Val-2; Ala-3-psi(CS-NH)-Trp-4]segetalin B, and thiosegetalin B2 [Gly-1-psi(CS-NH)-Val-2; Trp-4-psi(CS-NH)-Ala-1]segetalin B. Thiosegetalin A2 only showed estrogen-like activity against ovariectomized rats. On the basis of their conformations analysed by NMR experiments, the backbone conformation was considered to play an important role in estrogen-like activity for segetalins.

[Stereochemical structure of d-borneol in "the Japanese Standards of Food Additives"].

d-Borneol is shown at "The Japanese Standards of Food Additives" the sixth edition. Though the absolute stereochemistry of this compound is described as 1S, 2R-form, the opposite optical rotation for the same structure is described in other literatures. The application of improved Mosher's method to d-borneol resulted in 1R, 2S-form for its absolute stereochemistry.

Antiandrogenic phenolic constituents from Dalbergia cochinchinensis.

Four new compounds, 9-hydroxy-6,7-dimethoxydalbergiquinol, 6-hydroxy-2,7-dimethoxyneoflavene, 6,4'-dihydroxy-7-methoxyflavan and 2,2',5-trihydroxy-4-methoxybenzophenone, in addition to eight known phenolic compounds including 7-hydroxy-6-methoxyflavone, have been isolated from the stems of Dalbergia cochinchinensis. Their structures were established by spectroscopic techniques including one- and two-dimensional NMR methods. The first two compounds showed potent inhibitory activity towards 5 alpha-dihydrotestosterone (DHT) which binds with an androgen receptor to form a DHT-receptor complex that causes androgen-dependent disease.

A cyclic heptapeptide from Vaccaria segetalis.

A new cyclic heptapeptide, segetalin E, cyclo(-Gly-Tyr-Val-Pro-Leu-Trp-Pro-), has been isolated from the seeds of Vaccaria segetalis and the structure elucidated by extensive two-dimensional NMR methods and chemical degradation.

Synthesis and characterization of polymer-coated mixed-functional stationary phases with several different hydrophobic groups for direct analysis of biological samples by liquid chromatography.

Three types of polymer-coated mixed-functional (PCMF) silica column-packing materials for the direct analysis of biological liquids have been synthesized. These packing materials all have polyoxyethylene groups as their hydrophilic part but differ in their hydrophobic part (methyl groups for Me-POE, phenyl groups for Ph-POE, and octyl groups for Oc-POE). Retention characteristics with respect to several drug molecules, and protein recovery, were studied for each of the three types with different amounts of hydrophobic groups attached. Of the PCMFs prepared, Oc-POE showed the greatest overall retention, and Me-POE displayed the greatest protein recovery.

Cytotoxic aromatic triterpenes from Maytenus ilicifolia and Maytenus chuchuhuasca.

The isolation and structure elucidation of four cytotoxic aromatic triterpenes [1-4] along with three known quinoid triterpenes [5-7] from the South American medicinal plants Maytenus ilicifolia and M. chuchuhuasca are described. The structures of these aromatic triterpenes contained aromatized A rings and C-6 oxygenated B rings, and were elucidated by 1H- and 13C-nmr spectroscopic studies and by X-ray crystallographic analysis of 3.

High-sensitivity analysis of sialyl-oligosaccharide glycosylation sites in glycoproteins by miniaturized tryptic digestion and microcolumn liquid chromatography.

A highly sensitive analytical procedure was developed to assess the site of glycosylation in a model glycoprotein, bovine fetuin. First, sample cleavage with immobilized trypsin and the peptide map development are accomplished by microcolumn liquid chromatography. Second, the sialic acids content is measured fluorometrically using their precolumn conversion to quinoxaline derivatives. A unique preconcentration system was developed to secure sensitivity of the second measurement.

Separation of fluorescent oligosaccharide derivatives by microcolumn techniques based on electrophoresis and liquid chromatography.

Various aldose oligosaccharides can be quantitatively derivatized into primary amines for subsequent reaction with fluorogenic reagents, such as 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde or 3-benzoyl-2-naphthaldehyde. Capillary electrophoresis (CE) and microcolumn liquid chromatography (LC), coupled with laser-induced fluorescence detection, were evaluated as a means of separating complex oligosaccharide mixtures. Whereas microcolumn LC and open-tubular CE appear confined in their utility to relatively small oligosaccharides, unprecedented results were obtained with polyacrylamide gel-filled capillaries on hydrolyzed malto-oligosaccharides and enzymatically degraded samples of chondroitin sulfate and hyaluronic acid.

A cytotoxic substance from Sangre de Grado.

Taspine has been isolated as a cytotoxic substance from Sangre de Grado, sap of Croton palanostigma (Euphorbiaceae), by bioassay guided fractionation. The cytotoxicity (IC50) of taspine was found to be 0.39 microgram/ml against KB cells and 0.17 microgram/ml against V-79 cells.

Capillary electrophoresis of amino sugars with laser-induced fluorescence detection.

3-(4-Carboxybenzoyl)-2-quinolinecarboxaldehyde has been utilized as a precolumn derivatization agent for various amino sugars. Constituents of various biological mixtures can be converted to highly fluorescent isoindole derivatives, separated by high-performance capillary electrophoresis and determined at attomole (10(-18) mol) levels by a laser-induced fluorescence detector. This method has been applied to the analysis of monosaccharides and acid-hydrolyzed polysaccharides. Carbohydrate moieties derived from a glycoprotein were also tagged and determined.

Ultrasensitive fluorometric detection of carbohydrates as derivatives in mixtures separated by capillary electrophoresis.

Reducing monosaccharides and oligosaccharides, after reductive amination, were separated and detected as their 3-(4-carboxybenzoyl)-2-quinolinecarboxaldehyde (CBQCA) derivatives by capillary electrophoresis/laser-induced fluorescence. Under optimized conditions, the minimum detectable quantities for monosaccharide solutes were assessed at low attomole levels (0.5 amol for the CBQCA derivative of galactose). The system has shown considerable promise for high-sensitivity analysis of both neutral and amino sugars in glycoproteins. Complex oligosaccharides, isolated from bovine fetuin by hydrazinolysis, were also successfully "mapped."