Synthesis of Analogs of Optically Active α-Ionylideneacetic Acid

The Wittig reaction of (?)-α-ionone (VIa) with carbethoxymethylenetriphenylphosphorane afforded (?)-ethyl α-ionylideneacetate (VIIa). tert-Butyl chromate oxidation of the above ester (VIIa) gave (?)-ethyl 4′-keto-α-ionylideneacetate (VIlla). Selenium dioxide oxidation of (?)-α-ionone (IVa) in ethanol afforded (?)-1′-hydroxy-α-ionone (X), which reacted with car-bethoxymethylenetriphenylphosphorane to give (?)-ethyl 1′-hydroxy-α-ionylideneacetate (XI). tert-Butyl chromate oxidation of the hydroxy-ester (XI) gave (?)-ethyl abscisate (XII) and ethyl 3′-keto-β-ionylideneacetate (XIII). The sensitized photooxidation of ethyl dehydro-β-ionylideneacetate (XVI) using chlorophyll was attempted.     

Interaction of Tea Catechins with Lipid Bilayers Investigated by a Quartz-Crystal Microbalance Analysis

The quartz-crystal microbalance (QCM) technique was applied to investigate the interaction of tea catechins with lipid bilayers. The association constants obtained from the frequency changes of QCM revealed that (?)epicatechin gallate and (?)epigallocatechin gallate interacted with 1,2-dimyristoyl-sn-glycero-3-phosphocholine ca. 1000 times more strongly than (?)epicatechin and (?)epigallocatechin. The results exhibited good correlation with the strength of biological activity.     

Identification and Biological Evaluation of Secondary Metabolites from the Endolichenic Fungus Aspergillus versicolor

A chemical investigation of the endolichenic fungus Aspergillus versicolor (125a), which was found in the lichen Lobaria quercizans, resulted in the isolation of four novel diphenyl ethers, named diorcinols F–H ( 1 – 3 , resp.) and 3‐methoxyviolaceol‐II ( 4 ), eight new bisabolane sesquiterpenoids, named (?)‐(R)‐cyclo‐hydroxysydonic acid ( 5 ), (?)‐(7S,8R)‐8‐hydroxysydowic acid ( 6 ), (?)‐(7R,10S)‐10‐hydroxysydowic acid ( 7 ), (?)‐(7R,10R)‐iso‐10‐hydroxysydowic acid ( 8 ), (?)‐12‐acetoxy‐1‐deoxysydonic acid ( 9 ), (?)‐12‐acetoxysydonic acid ( 10 ), (?)‐12‐hydroxysydonic acid ( 11 ), and (?)‐(R)‐11‐dehydrosydonic acid ( 12 ), two new tris(pyrogallol ethers), named sydowiols D ( 13 ) and E ( 14 ), and fifteen known compounds, 15 – 29 . All of the structures were determined by spectroscopic analyses, and a number of them were further identified through chemical transformations and electronic circular dichroism (ECD) calculations. Preliminary bioassays of these isolates for the determination of their inhibitory activities against the fungus Candida albicans, and their cytotoxicities against the human cancer cell lines PC3, A549, A2780, MDA‐MB‐231, and HEPG2 were also evaluated.     

Conversion of ( + )-Carvone by Pseudomonas ovalis,Strain 6-1 (1)

The conversion of (+)-carvone by Pseudomonas ovalis, strain 6-1, was investigated. (+)-Carvone was found to be reduced to (?)-isodihydrocarvone, (?)-isodihydrocarveol, (?)-neoisodihydrocarveol, (?)-dihydrocarvone, (?)-neodihydrocarveol, and (+)-dihydrocarveol, of which the former three were the major products.

From these results, it was postulated that Pseudomonas ovalis, strain 6-1, has different pathways for (+)-carvone and (?)-carvone, respectively; (+)-carvone is converted via (?)- isodihydrocarvone to (?)-isodihydrocarveol and (?)-neoisodihydrocarveol, whereas (?)- carvone is converted via (+)-dihydrocarvone to (?)-dihydrocarveol.

Stereochemical structures of four isomers of dihydrocarveols were also discussed on the basis of PMR results.     

Synthesis of (+)-(R)- and (−)-(S)-5-hydroxy-2-methyl-2-dipropylaminotetralin: Effects on rat hippocampal output of 5-HT, 5-HIAA,and DOPAC as determined by in vivo microdialysis

Racemic 5-methoxy-2-methyl-2-dipropylaminotetralin ( 3 ) has been prepared by a short synthetic route, in which the N,N-dipropyliminium perchlorate of 5-methoxy-2-tetralone ( 4 ) is a key intermediate. Racemic 3 was resolved by crystallization of the corresponding diastereomeric di-p-toluoyltartrates. The enantiomeric excess (%ee) of the phenolic derivatives of (+)-(R)- and (?)-(S)-3 [(+)-(R)- and (?)-(S)-2] was determined by ¹HNMR spectroscopic analysis of the corresponding diastereomeric (?)-(R)-1,1′-binaphthyl-2,2′-diylphosphoric acid salts utilizing ¹³C satellites. X-ray crystallography established the absolute configuration of (?)-(S)-2 · HCl. The enantiomers of 2 were tested for hippocampal output of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, and dihydroxyphenylacetic acid in rats by use of in vivo microdialysis. The (?)-(S)-enantiomer appeared to affect 5-HT-turnover, whereas (+)-(R)- 2 was inactive. Results obtained provide support for the previously reported hypothesis that the inactivity of (?)-(S)- 2 at central DA receptors is caused by the steric bulk of the C(2)-methyl group. This makes it possible to define a “DA D2 receptor essential volume.” © 1993 Wiley-Liss, Inc.     

In Vitro Antioxidative Activity of (−)-Epicatechin Glucuronide Metabolites Present in Human and Rat Plasma

Recently we identified four conjugated glucuronide metabolites of epicatechin, (?)-epicatechin-3′-O-glucuronide (E3′G), 4′-O-methyl-(?)-epicatechin-3′-O-glucuronide (4′ME3′G), (?)-epicatechin-7-O-glucuronide (E7G) and 3′-O-methyl-(?)-epicatechin-7-O-glucuronide (3′ME7G) from plasma and urine. E3′G and 4′ME3′G were isolated from human urine, while E7G and 3′ME7G were isolated from rats that had received oral administration of (?)-epicatechin (Natsume et al. (2003), Free Radic. Biol. Med. 34, 840–849). It has been suggested that these metabolites possess considerable in vivo activity, and therefore we carried out a study to compare the antioxidant activities of the metabolites with that of the parent compound. This was achieved by measuring superoxide scavenging activity, reduction of plasma TBARS production and reduced susceptibility of low-density-lipoprotein (LDL) to oxidation. (?)-Epicatechin was found to have more potent antioxidant activity than the conjugated glucuronide metabolites. Both (?)-epicatechin and E7G had marked antioxidative properties with respect to superoxide radical scavenging activity, plasma oxidation induced by 2,2′-azobis-(2-aminopropane) dihydrochloride (AAPH) and LDL oxidation induced by copper ions or 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (MeO-AMVN). In contrast, the other metabolites had light antioxidative activities over the range of physiological concentrations found in plasma.     

Bevantolol hydrochloride (nc-1400): Absolute configuration and direct separation of the enantiomers

Synthesis of (?)-bevantolol hydrochloride from 3,4-dimethoxyphenethylamine and (S)-(+)-m-tolyl glycidyl ether derived from (R)-(?)-epichlorohydrin established the absolute configuration of the (+) and (?) enantiomer as R and S, respectively. The purity of the enantiomers was determines using a chiral cellulose column (CHIRALCEL OD®) which allowed direct separation of the enantiomers. A separation factor (α) of 4.20 and a resolution factor (Rs) of 9.21 were obtained. © 1995 Wiley-Liss, Inc.     

Colchicinoids from Colchicum crocifolium Boiss.: a case study in dereplication strategies for (-)-colchicine and related analogues using LC-MS and LC-PDA techniques

As a part of a project designed to investigate Colchicum species in Jordan, the chemical constituents of Colchicum crocifolium Boiss. (Colchicaceae) were investigated using LC‐MS and LC–UV/Vis PDA. A decision tree for working with colchicinods has been developed by incorporating data from LC‐UV/PDA and LC‐MS. This dereplication strategy draws upon the UV/PDA spectra to classify compounds into one of four structural groups and combines this with retention time and mass spectra/molecular weight to identify the compounds. This strategy was applied on a small amount of extract (2 mg) of Colchicum crocifolium to dereplicate 10 known compounds from four different structural groups, namely (?)‐demecolcine, 2‐demethyl‐(?)‐colchicine or3‐demethyl‐(?)‐colchicine, N‐deacetyl‐(?)‐colchicine, (?)‐colchiciline, (?)‐colchicine, β‐lumidemecolcine, 2‐demethyl‐β‐lumicolchicine or 3‐demethyl‐β‐lumicolchicine, N,N‐dimethyl‐N‐deacetyl‐β‐lumicornigerine, (?)‐isoandrocymbine and (?)‐autumnaline. Furthermore, a new compound was identi?ed as N,N‐dimethyl‐N‐deacetyl‐(?)‐cornigerine. Three compounds, which had molecular ions at m/z 325, 340 and 374, could not be dereplicated into any obvious structural classes that have been isolated in our laboratories previously or reported in the literature. Copyright © 2008 John Wiley & Sons, Ltd.     

Pluripotency of a polyploid H1 (ES) cell system without leukaemia inhibitory factor

Objectives: Tetraploid cells are strictly biologically inhibited from composition of embryos; by the same token, only diploid cells compose embryos. However, the distinction between diploid and tetraploid cells in development has not been well explained. To examine pluripotency of polyploid ES cells, a polyploid embryonic stem (ES)‐cell system was prepared. Materials and methods: Diploid, tetraploid, pentaploid, hexaploid, octaploid and decaploid H1 (ES) cells (2H1, 4H1, 5H1, 6H1, 8H1 and 10H1 cells, respectively) were cultured for about 460 days in L15F10 medium without leukaemia inhibitory factor (LIF). The cells cultured under LIF‐free conditions were denoted as 2H1(?), 4H1(?), 5H1(?), 6H1(?), 8H1(?) and 10H1(?) cells, respectively. Pluripotency and gene expression were examined. Results: Ploidy alteration of H1(?) cells was similar to that of H1 cells. The polyploid H1(?) cells showed positive activity of alkaline phosphatase, suggesting that they maintained pluripotency in vitro without LIF. The polyploid H1(?) cells formed teratocarcinomas in mouse abdomen, suggesting they could differentiate in mouse abdomen in vivo. 2H1, 4H1 and polyploid H1(?) cells expressed nanog, oct3/4 and sox2 genes, suggesting that they fulfilled the criteria of ES cells. Nanog gene was significantly over‐expressed in 4H1 and polyploid H1(?) cells, suggesting that overexpression of nanog gene was a characteristic of polyploid H1 cells. Conclusion: Polyploid H1 (ES) cells retained pluripotency in vitro, without LIF with nanog over‐expression.     

Aggregation pheromone of the Oriental spruce engraver Pseudips orientalis

• 1 Volatiles from the hindgut extracts of males of the Oriental spruce engraver Pseudips orientalis (Wood & Yin) (Coleoptera: Curculionidae, Scolytinae) of different phases of gallery development were analyzed by gas chromatography‐mass spectrometry‐flame ionization detection (GC‐MS/FID) with both polar and enantioselective columns.
• 2 GC‐MS/FID analyses showed that unmated males or males mated with one female produced approximately 95%‐(?)‐ipsenol and (?)‐cis‐verbenol as major components, as well as (?)‐trans‐verbenol, myrtenol, approximately 70%‐(+)‐ipsdienol and (?)‐verbenone as minor or trace components. The release of these male‐produced compounds was confirmed by GC analysis of an aeration sample of a P. orientalis‐infested spruce log. Mating reduced production of the male‐specific hindgut volatiles.
• 3 A field‐trapping bioassay in Qinghai, China, showed that a ternary blend containing two major components, 97%‐(?)‐ipsenol (i.e. close to naturally produced enantiomeric ratio) and (?)‐cis‐verbenol, plus a minor component (?)‐trans‐verbenol, caught significantly more P. orientalis beetles (♂: ♀ = 1: 2.7) compared with the unbaited control. Subtraction of (?)‐trans‐verbenol from the active ternary blend had no significant effect on trap catches. The addition of (±)‐ipsdienol (at 0.2 mg/day release) to the active ternary or binary blends significantly interrupted their trap catches. Replacing 97%‐(?)‐ipsenol with (±)‐ipsenol in the ternary blend significantly reduced trap catches to a level that was no different from the blank control.
• 4 Pseudips species were sister to all other Ipini genera in a phylogeny reconstructed with mitochondrial cytochrome oxidase I DNA data for 51 Ipini and outgroup species.
• 5 The results obtained suggest that the two major components, 95%‐(?)‐ipsenol and (?)‐cis‐verbenol (at approximately 4–5 : 1), produced by unmated fed males, are probably the primary aggregation pheromone components for P. orientalis. In light of the phylogeny, the use of terpenoid semiochemicals as pheromones probably occurred early in the evolution of Ipini and these semiochemical blends were subsequently modified in the process of speciation.

     

Biotransformations. XIX. Reduction of some terpenic ketones by means of immobilized cells of rhodotorula mucilaginosa

Reduction of (?)-menthone ((?)- 1 ), (+)-(R)-methyl-α-campholenone ((+)- 2 ), (+)-carvone ((+)- 3 ), and eucarvone ( 4 ) was carried out by means of cells of the Rhodotorula mucilaginosa species immobilized in polyacrylamide gel. Alcohols with the (S)-configuration, (+)-neomenthol ((+)- 1a ), (+)-(R)-methyl-α-campholenol ((+)- 2a ), (?)-neoisodihydrocarveol ((?)- 3a ), dihydroeucarveol ((?)- 4a ), and small amounts of (?)-dihydroeucarvone ((?)- 5 ), were obtained. The cells of R. mucilaginosa maintained after this reaction ability to reduce standard acetophenone to (?)- 1 -phenyl- 1 -ethanol.     

Effect of the structure of dietary epoxylignan on its cytotoxic activity: relationship between the structure and the activity of 7,7′-epoxylignan and the introduction of apoptosis by caspase 3/7

We compared the cytotoxic activities of dietary epoxylignans and their stereoisomers and found (?)-verrucosin, which is (7S,7′R,8R,8′R)-7,7′-epoxylignan, to be the most cytotoxic epoxylignan against HeLa cells (IC₅₀ = 6.6 μM). On the other hand, the activity was about a factor of 10 less against HL-60. In this research on the relationship between the structure and cytotoxic activity of (?)-verrucosin 13, the 7-(4-methoxyphenyl)-7′-(3,4-dimethoxyphenyl) derivative 60, for which the activity (IC₅₀ = 2.4 μM) is three times greater than (?)-verrucosin 13, was discovered. The induction of apoptosis by caspase 3/7 was observed upon treatment with the (?)-verrucosin derivative.     

Pyruvate Decarboxylase Catalysed Formation of Terpenoid α-hydroxy Ketones

Enzyme extracts of the wild type yeast Zygosaccharomyces bisporus were applied for the pyruvate decarboxylase catalysed condensation of pyruvate and (R)-(+)-and (S)-(?)-perillyl aldehyde, (±)-citronellal, neral, geranial or (R)-(?)-myrtenal to form novel α-hydroxy ketones. Best yields were obtained when the transformation medium contained 25% (v/v) of the cosolvent N,N-dimethylformamide. Conversion of (R)-(+)-perillyl aldehyde to (1R)-1-hydroxy-1-[(4’R)-4’-isopropenyl-1-cyclohexen-1-yl]-2-propanone proceeded highly stereospecifically (>99% de), whereas the stereoselectivity was somewhat less in the transformation of (S)-(?)-perillyl aldehyde (58% de) and (R)-(?)-myrtenal (92% de). All of the new compounds imparted characteristic odour impressions as determined by means of GC-olfactometry.     

Stereoselective distribution of hydroxychloroquine in the rabbit following single and multiple oral doses of the racemate and the separate enantiomers

Hydroxychloroquine (HCQ) stereoselective distribution was investigated in rabbits after 20 mg/kg po of racemic-HCQ (rac-HCQ) and 20 mg/kg po of each enantiomer, 97% pure (?)-(R)-HCQ and 99% pure (+)-(S)-HCQ. Concentrations were 4 to 6 times higher in whole blood than in plasma. Melanin did not affect plasma and whole blood levels since concentrations did not differ between pigmented and nonpigmented animals. After single and multiple doses of the separate enantiomers, only 5–10% of the antipode could be measured, in blood or plasma. Therefore, there was no significant interconversion from one enantiomer into the other. Following rac-HCQ, plasma (+)-(S)-levels always surpassed (?)-(R)-ones while in whole blood, (?)-(R)-HCQ concentrations were always the highest. When the enantiomers were administered separately, blood concentrations achieved after (?)-(R)-HCQ were higher, especially after multiple doses. These observations suggest that (?)-(R)-HCQ is preferentially concentrated by cellular components of blood. This enantioselective distribution of HCQ could be secondary to a stereoselective protein binding to plasma proteins, although a more specific binding of (?)-(R)-HCQ to blood cells cannot be ruled out. Since in whole blood (?)-(R)-HCQ is retained in cellular components, metabolism would favour the more available (+)-(S)-enantiomer. © 1994 Wiley-Liss, Inc.     

Conversion of (−)-Carvotanacetone and (+)-Carvotanacetone by Pseudomonas ovalis,Strain 6–1

As a part of series on the biochemical reduction of terpenes, the conversion of (?)-carvotanacetone (I) and (+)-carvotanacetone (II) by Pseudomonas ovalis, strain 6–1, has been studied.

By the action of the microorganism, I was reduced to give (+)-carvomenthone (III), (+)-neocarvomenthol (IV), and (?)-carvomenthol (V), whereas II was also reduced to (?)-isocarvomenthone (VI), (?)-carvomenthone (VII), (?)-isocarvomenthol (VIII), and (?)-neoisocarvomenthol (IX); of which III, VI and IX are the major products.

The metabolic pathways of I and II and mechanism of stereospecific hydrogenation are also discussed.     

Purification and characterization of a novel O-methyltransferase from Flammulina velutipes

An enzyme catalyzing the methylation of phenolic hydroxyl groups in polyphenols was identified from mycelial cultures of edible mushrooms to synthesize O-methylated polyphenols. Enzyme activity was measured to assess whether methyl groups were introduced into (?)-epigallocatechin-3-O-gallate (EGCG) using SAM as a methyl donor, and (?)-epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3″Me), (?)-epigallocatechin-3-O-(4-O-methyl)-gallate (EGCG4″Me), and (?)-epigallocatechin-3-O-(3,5-O-dimethyl)-gallate (EGCG3″,5″diMe) peaks were detected using crude enzyme preparations from mycelial cultures of Flammulina velutipes. The enzyme was purified using chromatographic and two-dimensional electrophoresis. The purified enzyme was subsequently analyzed on the basis of the partial amino acid sequence using LC–MS/MS. Partial amino acid sequencing identified the 17 and 12 amino acid sequences, VLEVGTLGGYSTTWLAR and TGGIIIVDNVVR. In database searches, these sequences showed high identity with O-methyltransferases from other mushroom species and completely matched 11 of 17 and 9 of 12 amino acids from five other mushroom O-methyltransferases.     

Conversion of (−)-Carvone and (+)-Carvone by a Strain of Aspergillus niger

The conversion of (?)-carvone and (+)-carvone by a strain of Aspergillus niger was studied as one of the series of biochemical reduction of terpenes.

(?)-Carvone was found to be reduced essentially to (+)-neodihydrocarveol, although (+)-dihydrocarvone and (+)-isodihydrocarvone were also formed in small amounts, whereas (+)-carvone was converted to (?)-isodihydrocarvone, (?)-isodihydrocarveol, (?)-neoisodihydrocarveol, (?)-dihydrocarvone, (?)-neodihydrocarveol, and (+)-dihydrocarveol, of which the former three were the major products.

The metabolic pathways for (?)-carvone and (+)-carvone by the strain of Aspergillus niger are discussed and the results on microbial and chemical reductions of carvone and dihydrocarvone are summarized.     

The Inhibition of α-Amylase by Tea Polyphenols

The inhibition of α-amylase from human saliva by polyphenolic components of tea and its specificity was investigated in vitro. Four kinds of green tea catechins, and their isomers and four kinds of their dimeric compounds (theaflavins) produced oxidatively during black tea production were isolated. They were (?)-epicatechin (EC), (?)-epigallocatechin (EGC), (?)-epicatechin gallate (ECg), (?)-epigallocatechin gallate (EGCg), (?)-catechin (C), (?)-gallocatechin (GC), (?)-catechin gallate (Cg), (?)-gallocatechin gallate (GCg), theaflavin (TF1), theaflavin monogallates (TF2A and TF2B), and theaflavin digallate (TF3). Among the samples tested, EC, EGC, and their isomers did not have significant effects on the activity of α-amylase. All the other samples were potent inhibitors and the inhibitory effects were in the order of TF3>TF2A>TF2B>TFl>Cg> GCg > ECg > EGCg. The inhibitory patterns were noncompetitive except for TF3.     

Direct high-performance liquid chromatographic separation of penbutolol enantiomers on a cellulose tris-3,5-dimethylphenyl carbamate chiral stationary phase

Penbutolol is a β-adrenoceptor blocking agent, and it contains the clinically relevant (?)-S-enantiomer. It was reported that the (+)-R-enantiomer of penbutolol is pharmacologically 50 times less active than the (?)-S-isomer in β-sympatholysis and without intrinsic sympathomimetic activity and refractory period in the heart muscle. Furthermore, the (+)-R-enantiomer does possess mutagenic activity. A high-performance liquid chromatographic (HPLC) method is described for direct identification, stereochemical separation, and quantitation of (+)-R-enantiomer in the clinically used (?)-S-isomer. The method involves the use of cellulose tris-3,5-dimethylphenyl carbamate chiral stationary phase coated on silica gel (OD-Chiralcel column). The capacity factors (k′) for the first eluted enantiomer and stereochemical separation factor (α) obtained were 1.32 and 1.98, respectively. The maximum stereochemical resolution factor (R) was 5.05. The method could be applied for optical purity determination of (?)-(S)-penbutolol in pharmaceutical formulation to detect for the presence of the undesirable (+)-R-enantiomer.