Superbanone, A New 2-Aryl-3-benzofuranone and Other Bioactive Constituents from the Tube Roots of Butea superba.

Phytochemical investigation from the tube roots of Butea superba, led to the isolation and identification of a new 2-aryl-3-benzofuranone named superbanone (1), one benzoin, 2-hydroxy-1-(2-hydroxy-4-methoxyphenyl)-2-(4-methoxyphenyl)ethanone (2), eight pterocarpans (3 - 10), and eleven isoflavonoids (11 - 21). Compound 2 was identified for the first time as a natural product. The structure of the isolated compounds was elucidated using spectroscopic methods, mainly 1D- and 2D-NMR. The isolated compounds and their derivatives were evaluated for α-glucosidase inhibitory and antimalarial activities. Compounds 3, 7, 8, and 11 showed promising α-glucosidase inhibitory activity (IC50  = 13.71 ± 0.54, 23.54 ± 0.75, 28.83 ± 1.02, and 12.35 ± 0.36 µm, respectively). Compounds 3 and 11 were twofold less active than the standard drug acarbose (IC50  = 6.54 ± 0.04 µm). None of the tested compounds was found to be active against Plasmodium falciparum strain 94. On the basis of biological activity results, structure-activity relationships are discussed.

Development of a composite chiral stationary phase from BSA and ß-cyclodextrin-bonded silica.

A composite chiral stationary phase (CSP) derived from bovine serum albumin (BSA) and ß-cyclodextrin (CD)-bonded silica was prepared. 2,4,6-Trichloro-1,3,5-triazine was used as a cross-linker. The obtained CSP was applied to the enantioseparation of tryptophan, hydrobenzoin, phenylalanine and mandelic acid. The influences of eluent pH value, organic modifier and column temperature on the retention and enantioseparation were discussed. Tryptophan and hydrobenzoin achieved excellent resolution on the composite CSP. For tryptophan, the highest selectivity, 2.79, was achieved with 1% of methanol at pH 8.0. For hydrobenzoin, the selectivity could reach 1.42. The chromatographic results were compared with that on ß-CD-bonded or BSA-immobilized CSP.

High-performance liquid chromatographic enantioseparation of racemic drugs based on homochiral metal-organic framework.

Homochiral metal-organic frameworks with fine-tuned pore sizes/walls and large surface areas are promising porous materials for enantioseparation considering the traditional zeolite molecular sieves have no chirality. Using enantiopure pyridyl-functionalized salen [(N-(4-Pyridylmethyl)-L-leucine·HBr)] as a starting material, we have prepared a noninterpenetrated three-dimensional homochiral metal organic framework {[ZnLBr]·H2O}n, which was further used as a chiral stationary phase for high-performance liquid chromatography to enantioseparate racemic drugs, showing excellent performances in enantioseparation of drugs. The metal-organic framework can be regarded as a novel molecular sieve-like material with a chiral separation function based on the relative sizes of the chiral channels and the resolved molecules.

Preparation and enantioseparation of a new click derived ß-cyclodextrin chiral stationary phase.

A new cyclodextrin-derived chiral stationary phase (denoted as CDA-CSP) was synthesized by immobilizing mono(6(A)-azido-6(A)-deoxy)-per(p-chlorophenyl carbamoylated) ß-cyclodextrin derivative to alkynyl modified silica via click chemistry. This newly prepared CSP shows good enantioseparation performance for six chiral compounds (1-6), such as 4-phenyl-oxazolidine-2-thione, two kinds of aryl alcohols, substituted flavonoids and benzoin, in which baseline separation of Analytes 1-4 was achieved under the experimental conditions. The effects of column temperature, mobile phase pH and content of methanol on the enantioseparation characteristics of CDA-CSP were investigated in detail. Retention factor and resolution for Compound 3 gradually reduced with an increase of column temperature, and a good linear relationship was shown between napierian logarithm of selectivity factor and reciprocal of column temperature. In the pH range from 3.56 to 5.50, a change in pH hardly affected the resolution of Analyte 2. In addition, increasing methanol in the mobile phase resulted in rapid eluting of the analytes from the column in reversed-phase mode. The retention factors for Analytes 1 and 3 significantly decreased and their resolution showed different trends.

Cytotoxic deoxybenzoins and diphenylethylenes from Arundina graminifolia.

Eight new C-4-alkylated deoxybenzoins (1-8), three new diphenylethylenes (9-11), and five known diphenylethylenes were isolated from Arundina graminifolia. The structures of 1-11 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 9-11 are the first naturally occurring diphenylethylenes possessing a hydroxyethyl unit. Compounds 1-11 were evaluated for cytotoxicity against five human tumor cell lines. Compounds 4, 5, and 9-11 showed significant cytotoxicity against five cancer cell lines, with IC50 values ranging from 1.8 to 8.7 µM.

Chiral magnetic microspheres purified by centrifugal field flow fractionation and microspheres magnetic chiral chromatography for benzoin racemate separation.

Separation of enantiomers still remains a challenge due to their identical physical and chemical properties in a chiral environment, and the research on specific chiral selector along with separation techniques continues to be conducted to resolve individual enantiomers. In our laboratory the promising magnetic chiral microspheres Fe3O4@SiO2@cellulose-2, 3-bis (3,5-dimethylphenylcarbamate) have been developed to facilitate the resolution using both its magnetic property and chiral recognition ability. In our present studies this magnetic chiral selector was first purified by centrifuge field flow fractionation, and then used to separate benzoin racemate by a chromatographic method. Uniform-sized and masking-impurity-removed magnetic chiral selector was first obtained by field flow fractionation with ethanol through a spiral column mounted on the type-J planetary centrifuge, and using the purified magnetic chiral selector, the final chromatographic separation of benzoin racemate was successfully performed by eluting with ethanol through a coiled tube (wound around the cylindrical magnet to retain the magnetic chiral selector as a stationary phase) submerged in dry ice. In addition, an external magnetic field facilitates the recycling of the magnetic chiral selector.

Citrus fruit and fabacea secondary metabolites potently and selectively block TRPM3.

BACKGROUND AND PURPOSE: The melastatin-related transient receptor potential TRPM3 is a calcium-permeable nonselective cation channel that can be activated by the neurosteroid pregnenolone sulphate (PregS) and heat. TRPM3-deficient mice show an impaired perception of noxious heat. Hence, drugs inhibiting TRPM3 possibly get in focus of analgesic therapy. EXPERIMENTAL APPROACH: Fluorometric methods were used to identify novel TRPM3-blocking compounds and to characterize their potency and selectivity to block TRPM3 but not other sensory TRP channels. Biophysical properties of the block were assessed using electrophysiological methods. Single cell calcium measurements confirmed the block of endogenously expressed TRPM3 channels in rat and mouse dorsal root ganglion (DRG) neurones. KEY RESULTS: By screening a compound library, we identified three natural compounds as potent blockers of TRPM3. Naringenin and hesperetin belong to the citrus fruit flavanones, and ononetin is a deoxybenzoin. Eriodictyol, a metabolite of naringenin and hesperetin, was still biologically active as a TRPM3 blocker. The compounds exhibited a marked specificity for recombinant TRPM3 and blocked PregS-induced [Ca(2+)]i signals in freshly isolated DRG neurones. CONCLUSION AND IMPLICATIONS: The data indicate that citrus fruit flavonoids are potent and selective blockers of TRPM3. Their potencies ranged from upper nanomolar to lower micromolar concentrations. Since physiological functions of TRPM3 channels are still poorly defined, the development and validation of potent and selective blockers is expected to contribute to clarifying the role of TRPM3 in vivo. Considering the involvement of TRPM3 in nociception, TRPM3 blockers may represent a novel concept for analgesic treatment.

The novel phloroglucinol derivative BFP induces apoptosis of glioma cancer through reactive oxygen species and endoplasmic reticulum stress pathways.

Prenyl-phloroglucinol derivatives from hop plants have been shown to have anticancer activities. This study is the first to investigate the anticancer effects of the new phloroglucinol derivative (2,4-bis(4-fluorophenylacetyl)phloroglucinol; BFP). BFP induced cell death and anti-proliferation in three glioma, U251, U87 and C6 cells, but not in primary human astrocytes. BFP-induced concentration-dependently cell death in glioma cells was determined by MTT and SRB assay. Moreover, BFP-induced apoptotic cell death in glioma cells was measured by Hochest 33258 staining and fluorescence-activated cell sorter (FACS) of propidine iodine (PI) analysis. Treatment of U251 human glioma cells with BFP was also found to induce reactive oxygen species (ROS) generation, which was detected by a fluorescence dye used FACS analysis. Treatment of BFP also increased a number of signature endoplasmic reticulum (ER) stress markers glucose-regulated protein (GRP)-78, GRP-94, IRE1, phosphorylation of eukaryotic initiation factor-2α (eIF-2α) and up-regulation of CAAT/enhancer-binding protein homologous protein (CHOP). Moreover, treatment of BFP also increased the down-stream caspase activation, such as pro-caspase-7 and pro-caspase-12 degradation, suggesting the induction of ER stress. Furthermore, BFP also induced caspase-9 and caspase-3 activation as well as up-regulation of cleaved PARP expression. Treatment of antioxidants, or pre-transfection of cells with GRP78 or CHOP siRNA reduced BFP-mediated apoptotic-related protein expression. Taken together, the present study provides evidences to support that ROS generation, GRP78 and CHOP activation are mediating the BFP-induced human glioma cell apoptosis.

Effects of Litchi chinensis fruit isolates on prostaglandin E(2) and nitric oxide production in J774 murine macrophage cells.

BACKGROUND: Litchi chinensis is regarded as one of the 'heating' fruits in China, which causes serious inflammation symptoms to people. METHODS: In the current study, the effects of isolates of litchi on prostaglandin E(2) (PGE(2)) and nitric oxide (NO) production in J774 murine macrophage cells were investigated. RESULTS: The AcOEt extract (EAE) of litchi was found effective on stimulating PGE(2) production, and three compounds, benzyl alcohol, hydrobenzoin and 5-hydroxymethyl-2-furfurolaldehyde (5-HMF), were isolated and identified from the EAE. Benzyl alcohol caused markedly increase in PGE(2) and NO production, compared with lipopolysaccharide (LPS) as positive control, and in a dose-dependent manner. Hydrobenzoin and 5-HMF were found in litchi for the first time, and both of them stimulated PGE(2) and NO production moderately in a dose-dependent manner. Besides, regulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) mRNA expression and NF-κB (p50) activation might be involved in mechanism of the stimulative process. CONCLUSION: The study showed, some short molecular compounds in litchi play inflammatory effects on human.

Isolation of 2,4,4'-trihydroxydeoxybenzoin and 3'-hydroxydaidzein from soybean miso.

Two 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging compounds were isolated from soybean miso. They were determined to be 2,4,4'-trihydroxydeoxybenzoin and 3'-hydroxydaidzein on the basis of spectroscopic data. In the manufacturing process for soybean miso, 2,4,4'-trihydroxydeoxybenzoin appeared during culture aging, and the quantity of it increased in a time-dependent manner.

Achiral and chiral separations using MEKC, polyelectrolyte multilayer coatings, and mixed mode separation techniques with molecular micelles.

Mixed mode (MM) separation using a combination of MEKC and polyelectrolyte multilayer (PEM) coatings is herein reported for the separation of achiral and chiral analytes. Many analytes are difficult to separate by MEKC and PEM coatings alone. Therefore, the implementation of a MM separation provides several advantages for overcoming the limitations of these well-established methods. In this study, it was observed that achiral separations using MEKC and PEM coatings individually resulted in partial resolution of eight very similar aryl ketones when the molecular micelle (sodium poly(N-undecanoyl-L-glycinate)) concentration was varied from 0.25 to 1.00% w/v and the bilayer number varied from 2 to 4. However, when MM separation was introduced, baseline resolution was achieved for all eight analytes. In the case of chiral separations, temazepam, aminoglutethimide, benzoin, benzoin methyl ether, and coumachlor were separated using the three separation techniques. For chiral separations, the chiral molecular micelle, sodium poly(N-undecanoyl-L-leucylvalinate), was employed at concentrations of 0.25-1.50% w/v for both MEKC and PEM coatings. Overall, the results revealed partial separation with MEKC and PEM coatings individually. However, MM separation enabled baseline separation of each chiral mixture. The separation of achiral and chiral compounds from different compound classes demonstrates the versatility of this MM approach.

Preparation of novel beta-cyclodextrin chiral stationary phase based on click chemistry.

A facile strategy based on click chemistry for preparation of the structurally well-defined native beta-cyclodextrin (beta-CD) based chiral stationary phase (CSP) was proposed. The beta-CD CSP was evaluated by enatioseparation of benzoin, trans-stilbene oxide, Troger's base, bendroflumethiazide, ketoprofen, chlorthalidone, three flavanone compounds and two beta-adrenergic blocking agents under reversed phase high performance liquid chromatography. The chromatographic results demonstrate the chiral separation ability of click beta-CD CSP and illustrate the usefulness of click chemistry in the preparation of beta-CD based CSP.

Automated screening platform with isochronal-parallel analysis and conditioning for rapid method development of chiral separations.

An automated chiral separation-screening platform was developed, allowing separation analysis on one column while another column is simultaneously equilibrated with a different mobile phase (MP). The platform can be set up from usual HPLC components at moderate cost and it considerably speeds up the screening process, allowing numerous chromatographic conditions to be tested within a short period of time and leading to a significant gain in time and productivity in preparative separations.

Dynamic kinetic resolution of benzoins by lipase-metal combo catalysis.

The synthesis of some noncommercial racemic 1,2-diaryl-2-hydroxyethanones (benzoins) is described, optimizing the previously reported methodologies. In a further step, the kinetic resolution of these substrates is reported, obtaining conversions of around 50% and ee(p) higher than 99% in very short reaction times. As enzymatic catalyst, after screening of several enzymes, the lipase TL (from Pseudomonas stutzeri) was the most efficient, working in an organic solvent with a very low log P value, such as THF. Finally, the dynamic-kinetic resolution of different benzoins using a lipase-ruthenium-catalyzed transesterification in organic solvents is described for the first time, obtaining conversions up to 90% maintaining the excellent enantioselectivity in all cases.

Chiral separation of norlaudanosoline, laudanosoline, laudanosine, chlorthalidone, and three benzoin derivatives using amino acid based molecular micelles.

In this study, 18 polymeric single amino acid and dipeptide surfactants are examined, and their performances, in terms of enantioselectivity, are compared for norlaudanosoline, laudanosoline, laudanosine, chlorthalidone, benzoin, benzoin methyl, and benzoin ethyl enantiomers. Several aspects of amino acid-based polymeric surfactants including comparison of single amino acid versus dipeptide, amino acid order, steric effect, and effect of the position of the chiral center of dipeptide surfactants on the chiral selectivity of these optically active compounds are discussed.

Migration behavior and enantioseparation of hydrobenzoin and structurally related compounds in capillary zone electrophoresis with a dual cyclodextrin system consisting of heptakis-(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin and beta-cyclodextrin.

Migration behavior and enantioseparation of racemic hydrobenzoin and structurally related compounds, including benzoin and benzoin methyl ether, in CZE with a dual CD system consisting of heptakis-(2,3-dihydroxy-6-O-sulfo)-beta-CD (SI-S-beta-CD) and beta-CD as chiral selectors in the presence and absence of borate complexation at pH 9.0 were investigated. The results indicate that enantioseparation of hydrobenzoin is mainly governed by CD complexation of hydrobenzoin-borate complexes with SI-S-beta-CD when SI-S-beta-CD concentration is relatively high. Whereas CD complexation of hydrobenzoin-borate complexes with beta-CD plays a significant role in enantioseparation when SI-S-beta-CD concentration is comparatively low. The (S,S)-enantiomer of the hydrobenzoin-borate complex was found to interact more strongly than the corresponding (R,R)-enantiomer with both SI-S-beta-CD and beta-CD. These two types of CD show the same chiral recognition pattern, but they exhibit opposite effects on the mobility of the enantiomers of hydrobenzoin-borate complexes. Enantiomer migration reversal of hydrobenzoin occurred in the presence of borate complexation when varying the concentration of beta-CD, while keeping SI-S-beta-CD at a relatively low concentration. Binding constants of the enantiomers of benzoin-related compounds to beta-CD and those of hydrobenzoin-borate complexes to SI-beta-CD were evaluated; the mobility contributions of all complex species to the effective mobility of the enantiomers of hydrobenzoin as a function of beta-CD concentration in a borate buffer were analyzed. In addition, comparative studies on the enantioseparation of benzoin-related compounds with SI-S-beta-CD and with randomly sulfate-substituted beta-CD were made.

Effect of (+) or (-) camphorsulfonic acid additives to the mobile phase on enantioseparations of some basic drugs on a Chiralcel OD column.

This paper describes the modification of Chiralcel OD column properties by adsorption of (+) or (-) camphorsulfonic acids (CSAs) used as additives to the mobile phase. The effects on retention, selectivity and efficiency, of adsorption of (+) and (-) CSAs on a Chiralcel OD column were examined. Racemic anti-histamines, anti-malarial and anti-fungal drugs, namely doxylamine, miconazole, sulconazole, hydroxyzine, homochlorcyclizine, methoxypheniramine, cyclopentolate and ephedrine were investigated as chiral tested compounds. All the studied drugs have an amino nitrogen atom in their structure. Only the enantioseparation of ephedrine enantiomers with CSAs alone was studied on the Nucleosil stationary phase, and these results were compared with the results obtained on the Chiralcel OD phase. A new dynamically generated stationary phase, with very good enantioseparation ability towards the studied compounds, was obtained by the adsorption of (-) CSA on the Chiralcel OD column.

Enantioseparations of hydrobenzoin and structurally related compounds in capillary zone electrophoresis using heptakis(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin as chiral selector and enantiomer migration reversal of hydrobenzoin with a dual cyclodextrin system in the presence of borate complexation.

We investigated the enantioseparations of racemic hydrobenzoin, together with benzoin and benzoin methyl ether, in capillary electrophoresis (CE) using the single-isomer heptakis(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin (SI-S-beta-CD) as a chiral selector in the presence and absence of borate complexation and enantiomer migration reversal of hydrobenzoin with a dual CD system consisting of SI-S-beta-CD and beta-CD in the presence of borate complexation at pH 9.0 in a borate buffer. The enantioselectivity of hydrobenzoin increased remarkably with increasing SI-S-beta-CD concentration and the enantioseparation depended on CD complexation between hydrobenzoin-borate and SI-S-beta-CD. The (S,S)-enantiomer of hydrobenzoin-borate complexes interacted more strongly than the (R,R)-enantiomer with SI-S-beta-CD. The enantiomers of hydrobenzoin could be baseline-resolved in the presence of SI-S-beta-CD at a concentration as low as 0.1% w/v, whereas the three test analytes were simultaneously enantioseparated with addition of 0.3% w/v SI-S-beta-CD or at concentrations >2.0% w/v in a borate buffer and 0.5% w/v in a phosphate background electrolyte at pH 9.0. Compared with the results obtained previously using randomly sulfated beta-CD (MI-S-beta-CD) in a borate buffer, enantioseparation of these three benzoin compounds is more advantageously aided by SI-S-beta-CD as the chiral selector. The enantioselectivity of hydrobenzoin depended greatly on the degree of substitution of sulfated beta-CD. Moreover, binding constants of the enantiomers of benzoin compounds to SI-S-beta-CD and those of hydrobenzoin-borate complexes to SI-S-beta-CD were evaluated for a better understanding of the role of CD complexation in the enantioseparation and chiral recognition. Enantiomer migration reversal of hydrobenzoin could be observed by varying the concentration of beta-CD, while keeping SI-S-beta-CD at a relatively low concentration. SI-S-beta-CD and beta-CD showed the same chiral recognition pattern but they exhibited opposite effects on the mobility of the enantiomers.

Comparative studies on the enantioseparation of hydrobenzoin and structurally related compounds by capillary zone electrophoresis with sulfated beta-cyclodextrin as the chiral selector in the presence and absence of borate complexation.

Comparative studies on the enantioseparations of racemic hydrobenzoin, together with benzoin and benzoin methyl ether, in capillary zone electrophoresis using sulfated beta-cyclodextrin (S-beta-CD) as a chiral selector in the presence and absence of borate complexation were investigated. The influences of S-beta-CD concentration on the enantioseparation of benzoins in a borate buffer and a phosphate background electrolyte and the influences of the concentration and the pH of borate buffer containing S-beta-CD on the enantioseparation of hydrobenzoin were examined. The results indicate that, depending on the degree of strong borate complexation and comparatively weak CD complexation, the selectivity of the enantiomers of hydrobenzoin can be greatly reduced in a buffer system containing borate ions. Enantioseparation of hydrobenzoin is mainly governed by the interaction between hydrobenzoin-borate complexes and S-beta-CD in a borate buffer, whereas enantioseparation of benzoins is primarily determined by CD complexation in a phosphate background electrolyte. Effective enantioseparations of benzoins were simultaneously achieved with addition of S-beta-CD at a concentration greater than 3.0% (w/v) in a borate buffer and at a concentration greater than 2.5% (w/v) in a phosphate background electrolyte at pH 9.0.

Enantioseparation of benzoins and enantiomer migration reversal of hydrobenzoin in capillary zone electrophoresis with dual cyclodextrin systems and borate complexation.

Enantioseparations of racemic hydrobenzoin and structurally related compounds, including benzoin and benzoin methyl ether, in capillary zone electrophoresis (CZE) with dual cyclodextrin (CD) systems consisting of S-beta-CD (mixed isomers) and a neutral CD, including beta-CD and hydroxypropyl-beta-CD (HP-beta-CD), as chiral selectors in the presence of borate complexation at pH 9.0 were investigated. Effective enantioseparations of hydrobenzoin were achieved with addition of dual CD systems and also with neutral CDs in a borate buffer. The enantioseparation and migration behavior of hydrobenzoin in such an electrophoretic system are primarily governed by the interaction of the borate complex of hydrobenzoin with beta-CDs. The CD complexations of both hydrobenzoin and the borate complexes of hydrobenzoin with beta-CDs increase in the order S-beta-CD < HP-beta-CD < beta-CD. As a result, enantioseparations of hydrobenzoin with the use of dual CD systems consisting of S-beta-CD/beta-CD and S-beta-CD/HP-beta-CD as chiral selectors are more advantageous than that with the use of S-beta-CD alone. With these dual CD systems in the presence of borate complexation, the enantiomer migration reversal was observed for hydrobenzoin. The interactions of hydrobenzoin with neutral CDs and with S-beta-CD exhibit the same chiral recognition pattern, but opposite effect on the mobility of the enantiomers. The (S,S)-enantiomer of hydrobenzoin was found to interact more strongly than the (R,R)-enantiomer with neutral CDs. For comparison, enantioseparation of hydrobenzoin, together with benzoin and benzoin methyl ether, with dual CD systems in a phosphate background electrolyte at pH 9.0 was also examined. The migration order and enantioselectivity of these three benzoins depend on the degree of CD complexations between benzoins and both S-beta-CD and neutral CD in a phosphate background electrolyte. In addition, effective enantioseparations of hydrobenzoin were also achievable with addition of either beta-CD at concentrations greater than 1.0 mM or HP-beta-CD at concentrations exceeding 2.0 mM in a borate buffer at pH 9.0.