ABSTRACT
Fifty-eight phenolic compounds isolated from Phyllanthus emblica were screened and compared for their in vitro and in vivo antioxidant properties, as well as hyaluronidase (HAase) inhibitory activities. Among them, 20 compounds showed to be promising antioxidants due to the stronger scavenging activity in both DPPH radical and Danio rerio reactive oxygen species assays, while nine compounds were potential HAase inhibitors with 100-fold stronger activities than that of the positive control, DSCG. The structure activity relationship was discussed.
ABSTRACT
Four triterpenes were isolated from a traditional Japanese tea product produced by anaerobic microbial fermentation of heated green tea leaves (Camellia sinensis). Two of the compounds were novel and characterized by spectroscopic investigation to be 13,26-epoxy-3ß,11α-dihydroxyolean-12-one and 3ß,11α,13ß-trihydroxyolean-12-one. Two known triterpenes were identified as taraxastane-3ß,20ß-diol and taraxastane-3ß,20α-diol. These triterpenes were not detected in the original green tea leaves.
Subject(s)
Food Analysis , Food Microbiology , Oleanolic Acid/analysis , Tea/chemistry , AnaerobiosisABSTRACT
A bisabolane type of sesquiterpene was isolated from the culture medium of Amanita virgineoides BAS, together with two known compounds, including lignoren, and harziandion. The structure of the new compound "virgineol" was established using a combination of different NMR spectroscopy techniques, whereas the chemical structure of the known compound was identified as lignoren, and the structure of harziandion was confirmed by X-ray crystallographic analysis.
Subject(s)
Amanita/chemistry , Sesquiterpenes/chemistry , Crystallography, X-Ray/methods , Magnetic Resonance Spectroscopy/methods , Mycelium/chemistryABSTRACT
It is well-known that baicalin-berberine complex (1) precipitates in the water decoction of numerous Chinese Medicinal formulae containing Radix Scutellariae and Rhizoma Coptidis or Cortex Phellodendri. In the current study, ionic interaction between the carboxylate ion of baicalin and the quaternary ammonium ion of berberine was revealed to be responsible for the formation of 1 and wogonoside-berberine (2) by using FAB-MS and NMR titration experiments. In addition, nuclear Overhauser effect spectroscopy (NOESY) correlations observed in 1 and 2 suggested quite different conformation of the two complexes, which was further supported by the fact that the [α](D) of the canadine obtained by reduction of 1 is of an opposite sign to that obtained from 2. Partition coefficients (n-octanol/water) determination demonstrated 12-20 times larger partition coefficient of each complex (1, 2) than that of each single compound (baicalin, wogonoside, and berberine), indicating the significant role of the formation of the complex in the bioavailability enhancement of these pharmacologically active constituents.
Subject(s)
Berberine/chemistry , Coordination Complexes/chemistry , Flavanones/chemistry , Flavonoids/chemistry , Glucosides/chemistry , Drugs, Chinese Herbal/chemistry , Magnetic Resonance Spectroscopy , Molecular Conformation , Octanols/chemistry , Water/chemistryABSTRACT
A new benzyl benzoate glycoside and five new 3-deoxy-D-manno-2-octulosonic acid derivatives were isolated from the entire plant of Solidago decurrens together with three known compounds. Their structures were established by extensive analyses of their 1D and 2D NMR spectra and by comparison with physical data of known compounds.
Subject(s)
Benzoates/isolation & purification , Benzyl Alcohols/isolation & purification , Glucosides/isolation & purification , Solidago/chemistry , Sugar Acids/isolation & purification , Benzoates/chemistry , Benzyl Alcohols/chemistry , Glucosides/chemistry , Hong Kong , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Stereoisomerism , Sugar Acids/chemistryABSTRACT
Chromatographic separation of black tea polyphenols is too difficult to supply sufficient quantities of pure compounds for biological experiments. Thus, facile methods to prepare black tea constituents were desired. Treatment of epigallocatechin gallate with copper(II) chloride efficiently afforded an unstable quinone dimer, dehydrotheasinensin A, and subsequent treatment with ascorbic acid stereoselectively yielded theasinensin A. The latter is a dimer with an R-biphenyl bond, one of the major polyphenols found in black tea. The method is simpler and more effective than enzymatic preparation.
Subject(s)
Ascorbic Acid/chemistry , Benzopyrans/chemical synthesis , Biomimetic Materials/chemical synthesis , Catechin/analogs & derivatives , Copper/chemistry , Phenols/chemical synthesis , Tea/chemistry , Benzopyrans/chemistry , Biomimetic Materials/chemistry , Catechin/chemistry , Dimerization , Oxidation-Reduction , Phenols/chemistry , Polyphenols/chemical synthesis , Polyphenols/chemistry , StereoisomerismABSTRACT
Triterpene hexahydroxydiphenoyl (HHDP) esters have only been isolated from Castanopsis species, and the distribution of these esters in nature is of chemotaxonomical interest. In this study, the chemical constituents of the leaves of Castanopsis fissa were examined in detail to identify and isolate potential HHDP esters. Together with 53 known compounds, 3,4-di-O-galloyl-1-O-purpurogallin carbonyl quinic acid (1) and 3,24-(S)-HHDP-2α,3ß,23,24-tetrahydroxytaraxastan-28,20ß-olide (2) were isolated and their structures were elucidated by spectroscopic and chemical methods. The polyphenols of the leaves were mainly composed of galloyl quinic acids, triterpenes HHDP esters, ellagitannins and flavonol glycosides. In particular, the isolation yields of 1,3,4-trigalloyl quinic acid and compound 2 were 1.53% and 0.27%, respectively, from the fresh leaves. The presence of lipid soluble HHDP esters of oleanane-type triterpenes as one of the major metabolites is an important chemotaxonomical discovery. Lipase inhibition activities and ORAC values of the major constituents were compared. The triterpene HHDP ester showed moderate lipase inhibition activity and myricitrin gave the largest ORAC value.
Subject(s)
Benzocycloheptenes/chemistry , Fagaceae/chemistry , Quinic Acid/analogs & derivatives , Quinic Acid/chemistry , Triterpenes/chemistry , Benzocycloheptenes/isolation & purification , Esters , Plant Leaves/chemistry , Quinic Acid/isolation & purification , Triterpenes/isolation & purificationABSTRACT
Phenolic constituents of a new functional fermented tea produced by tea-rolling processing of a mixture (9:1) of tea leaves and loquat leaves were examined in detail. The similarity of the phenolic composition to that of black tea was indicated by high-performance liquid chromatography comparison with other tea products. Twenty-five compounds, including three new catechin oxidation products, were isolated, and the structures of the new compounds were determined to be (2R)-2-hydroxy-3-(2,4,6-trihydroxyphenyl)-1-(3,4,5-trihydroxyphenyl)-1-propanone 2-O-gallate, dehydrotheasinensin H, and acetonyl theacitrin A by spectroscopic methods. In addition, theacitrinin A and theasinensin H were obtained for the first time from commercial tea products. Isolation of these new and known compounds confirms that reactions previously demonstrated by in vitro model experiments actually occur when fresh tea leaves are mechanically distorted and bruised during the production process.
Subject(s)
Camellia sinensis/chemistry , Eriobotrya/chemistry , Flavonoids/analysis , Food Handling/methods , Phenols/analysis , Plant Leaves/chemistry , Tea/chemistry , Catechin/analysis , Catechin/chemistry , Fermentation , PolyphenolsABSTRACT
ent-Eudesmane sesquiterpenoids, 8,11-dihydroxy-2,4-cycloeudesmane, 11-hydroxy-2,4-cycloeudesman-8-one and 2,4-cyclo-7(11)-eudesmen-8-one, were isolated from the wood of Platycarya strobilacea, which has been used as an aromatic tree since at least the 18th century. On charring the wood, 2,4-cyclo-7(11)-eudesmen-8-one was detected in the smoke. In the charred wood, the concentrations of ellagitannins, such as galloyl pedunculagin, dramatically decreased, whereas concentrations of pentagalloyl glucose, and other gallotannins were relatively stable. In addition, two other compounds, the 6'-O-m- and p-digalloyl oak lactone precursor and the 3-O-methylellagic acid 4'-O-(4â³-O-galloyl)-xylopyranoside, were isolated from the charred wood along with m- and p-digallic acid.
Subject(s)
Juglandaceae/chemistry , Lactones/chemistry , Sesquiterpenes, Eudesmane/isolation & purification , Gallic Acid/analogs & derivatives , Gallic Acid/chemistry , Gallic Acid/isolation & purification , Japan , Molecular Structure , Sesquiterpenes, Eudesmane/chemistry , Wood/chemistryABSTRACT
Two new phenolic compounds, teadenol A (1) and teadenol B (2), were isolated from tea (Camellia sinensis L.) leaves fermented with Aspergillus sp. (PK-1, FARM AP-21280). The chemical structures of 1 and 2 were elucidated based on the analyses of their spectroscopic data. The absolute configurations of the structures of 1 and 2 were also certified by their biosynthetic preparation in the treatment of tea catechins with Aspergillus sp.
Subject(s)
Aspergillus/metabolism , Camellia sinensis/chemistry , Phenols/chemistry , Phenols/metabolism , Plant Leaves/chemistry , Fermentation , Magnetic Resonance SpectroscopyABSTRACT
The bark extract of Acacia mearnsii showed strong lipase and α-amylase inhibition activities. Fractionation of the extract by column chromatography and subsequent (13)C NMR and MALDI-TOF-MS analysis revealed that the active substances are proanthocyanidin oligomers mainly composed of 5-deoxyflavan-3-ol units. In addition, 4'-O-methylrobinetinidol 3'-O-ß-D-glucopyranoside, fisetinidol-(4α,6)-gallocatechin, and epirobinetinidol-(4ß,8)-catechin were isolated as new compounds, and their structures were determined from spectroscopic data. Furthermore, a modified thiol degradation method using strongly acidic conditions was applied to the extract to yield three thiol degradation products derived from robinetinidol units. This method is useful for characterizing acacia proanthocyanidins (wattle tannins).
Subject(s)
Acacia/chemistry , Lipase/antagonists & inhibitors , Proanthocyanidins/isolation & purification , Proanthocyanidins/pharmacology , alpha-Amylases/antagonists & inhibitors , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Pancreas/enzymology , Plant Bark/chemistry , Proanthocyanidins/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
Two new diketopiperazine derivatives, bacillusamides A (1) and B (2), have been isolated from the EtOAc extract of the sea urchin-derived Bacillus sp. along with the known cyclo(-L-pro-L-val-) (3), cyclo(-L-pro-L-tyr-) (4), cyclo(-L-pro-L-phe-) (5). These structures were elucidated by extensive spectroscopic methods. Furthermore, the absolute configurations of the amino acid residues were determined using Marfey's method. Compound 1 displayed weak antifungal activity against Aspergillus niger.
Subject(s)
Anti-Infective Agents/chemistry , Bacillus/chemistry , Diketopiperazines/chemistry , Sea Urchins/microbiology , Animals , Anti-Infective Agents/isolation & purification , Anti-Infective Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Antifungal Agents/pharmacology , Aspergillus niger/drug effects , Diketopiperazines/isolation & purification , Diketopiperazines/pharmacology , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Molecular ConformationABSTRACT
A new epicatechin oxidation product with a 3,6-dihydro-6-oxo-2H-pyran-2-carboxylic acid moiety was isolated from a commercially available post-fermented tea that is produced by microbial fermentation of green tea. The structure of this product was determined by spectroscopic methods. A production mechanism that includes the oxygenative cleavage of the catechol B-ring of (-)-epicatechin is proposed. In addition, polymeric polyphenols were separated from the post-fermented tea and partially characterised by (13)C NMR spectroscopy and gel-permeation chromatography. The polymers appear to be primarily composed of epigalloacetechin-3-O-gallate and the molecular weight (Mn) of the acetylated form was estimated to be â¼3500.
ABSTRACT
Two new iridoid diesters of glucopyranose were isolated from the aerial part of Linaria canadensis (L.) Dum. Eight known flavones, apigenin, diosmetin, genkwanin, luteolin, luteolin 7-O-glucoside, luteolin 7-O-glucuronide, genkwanin 4'-O-rutinoside, and quercetin 7-O-rutinoside were also isolated. The chemical structures of the isolated compounds were elucidated based on the analyses of the spectroscopic data.
Subject(s)
Iridoids/chemistry , Linaria/chemistry , Flavones/chemistry , Flavonoids/chemistry , Glucosides/chemistry , Luteolin/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , Quercetin/chemistryABSTRACT
Degradation of the black tea pigment theaflavin was examined in detail. Enzymatic oxidation of a mixture of epigallocatechin and epicatechin initially produced theaflavin, while prolonged reaction decreased the product. Addition of ethanol to the reaction mixture at the point when theaflavin began to decrease afforded four new products, together with theanaphthoquinone, a known oxidation product of theaflavin. The structures of the new products were determined by spectroscopic methods. One of the products was an ethanol adduct of a theanaphthoquinone precursor, and this reacted with theaflavin to give two further products. A product generated by coupling of theaflavin with epicatechin quinone was also obtained. The structures of the products indicate that oxidation and coupling with quinones are key reactions in the degradation of theaflavins. The degradation of theaflavin probably contributes to production of thearubigins.
Subject(s)
Biflavonoids/metabolism , Catechin/analogs & derivatives , Catechin/metabolism , Tea/chemistry , Biflavonoids/chemistry , Catechin/chemistry , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Oxidation-ReductionABSTRACT
In a project to produce a new fermented tea product from non-used tea leaves harvested in the summer, we found that kneading tea leaves ( Camellia sinensis ) with fresh loquat leaves ( Eriobotrya japonica ) accelerated the enzymatic oxidation of tea catechins. The fermented tea obtained by tea-rolling processing of tea and loquat leaves had a strong, distinctive flavor and a plain aftertaste, which differed from usual black, green, and oolong teas. The phenolic constituents were similar to those of black tea. However, the concentrations of theaflavin 3-O-gallate, theaflavin 3,3'-di-O-gallate, and thearubigins were higher in the tea leaves kneaded with loquat leaves than in tea leaves kneaded without loquat leaves. The results from in vitro experiments suggested that acceleration of catechin oxidation was caused by the strong oxidation activity of loquat leaf enzymes and a coupled oxidation mechanism with caffeoyl quinic acids, which are the major phenolic constituents of loquat leaves.
Subject(s)
Biflavonoids/analysis , Camellia sinensis , Catechin/analogs & derivatives , Catechin/metabolism , Eriobotrya , Gallic Acid/analogs & derivatives , Phenols/analysis , Plant Leaves/enzymology , Camellia sinensis/chemistry , Catechin/analysis , Eriobotrya/chemistry , Eriobotrya/enzymology , Fermentation , Food Handling/methods , Gallic Acid/analysis , Oxidation-Reduction , Plant Leaves/chemistry , Polyphenols , Taste , Tea/chemistryABSTRACT
Four new dammarane-type triterpene saponins named floranotoginsenosides A (1), B (2), C (3) and D (4), together with five known triterpene saponins, were isolated from the flowers of Panax notoginseng. Their structures were elucidated on the basis of spectral and chemical evidence.
Subject(s)
Drugs, Chinese Herbal/chemistry , Flowers/chemistry , Panax notoginseng/chemistry , Saponins/chemistry , Triterpenes/chemistry , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Saponins/isolation & purification , DammaranesABSTRACT
Hydrophobic catechin derivatives were produced by heating with natural aldehydes or allyl alcohols. (+)-Catechin or (-)-epigallocatechin-3-O-gallate was heated with trans-2-hexenal, citral, (+)-citronellal, geraniol, or phytol. Although each reaction generated complex mixtures of products, 11 compounds were isolated and characterized by spectroscopic methods. The unsaturated aldehydes were found to attach to the flavan A-ring. Besides C-C linkage between aldehyde and the C-8 and/or C-6 of the catechin A-ring, formation of ether linkages between unsaturated carbons of the aldehydes and phenolic hydroxyl groups was observed. The allyl alcohols, geraniol and phytols, reacted at the galloyl group as well as the A-ring. After partitioning between triglyceride and water, the lipid layer of the reaction products showed strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. In contrast, epigallocatechin-3-O-gallate was not transferred to the lipid layer.
Subject(s)
Aldehydes/chemistry , Catechin/chemistry , Free Radical Scavengers/chemistry , Propanols/chemistry , Triglycerides , Biphenyl Compounds , Catechin/analogs & derivatives , Hot Temperature , Picrates , Solubility , WaterABSTRACT
A new ellagitannin dimer named euscaphinin was isolated from the leaves of Euscaphis japonica (THUNB.) KANITZ. The structure of this dimer was determined on the basis of spectroscopic and chemical evidence. The resulting structure indicated that it was produced by intermolecular C-O oxidative coupling between the galloyl groups of molecules of 1(beta)-O-galloyl pedunculagin, the major ellagitannin of the leaves. The ellagitannins were not detected in the bark and wood part of the plant. This is the first example of the isolation of ellagitannins from Staphyleaceaeous plants.
Subject(s)
Hydrolyzable Tannins/isolation & purification , Magnoliopsida/chemistry , Dimerization , Hydrolyzable Tannins/chemistry , Molecular Conformation , Plant Bark/chemistry , Plant Leaves/chemistryABSTRACT
This review will discuss recent progress in the chemistry of secondary polyphenols produced during food processing. The production mechanism of the secondary polyphenols in black tea, whisky, cinnamon, and persimmon fruits will be introduced. In the process of black tea production, tea leaf catechins are enzymatically oxidized to yield a complex mixture of oxidation products, including theaflavins and thearubigins. Despite the importance of the beverage, most of the chemical constituents have not yet been confirmed due to the complexity of the mixture. However, the reaction mechanisms at the initial stages of catechin oxidation are explained by simple quinone-phenol coupling reactions. In vitro model experiments indicated the presence of interesting regio- and stereoselective reactions. Recent results on the reaction mechanisms will be introduced. During the aging of whisky in oak wood barrels, ellagitannins originating from oak wood are oxidized and react with ethanol to give characteristic secondary ellagitannins. The major part of the cinnamon procyanidins is polymerized by copolymerization with cinnamaldehyde. In addition, anthocyanidin structural units are generated in the polymer molecules by oxidation which accounts for the reddish coloration of the cinnamon extract. This reaction is related to the insolubilization of proanthocyanidins in persimmon fruits by condensation with acetaldehyde. In addition to oxidation, the reaction of polyphenols with aldehydes may be important in food processing.