astringin and polydatin

The flavin-dependent monooxygenase Sam5 was previously reported to be a bifunctional hydroxylase with a coumarte 3-hydroxylase and a resveratrol 3'-hydroxylase activity. In this article, we showed the Sam5 enzyme has 3'-hydroxylation activities for methylated resveratrol (pinostilbene and pterostilbene), hydroxylated resveratrol (oxyresveratrol) and glycosylated resveratrol (piceid) as substrates. However, the use of piceid, a glycone type stilbene, as a substrate for bioconversion experiments with the Sam5 enzyme expressed in,

Topics: Dinitrocresols; Escherichia coli; Flavins; Glucosides; Hydroxylation; Mixed Function Oxygenases; Plant Extracts; Resveratrol; Stilbenes

Wogonin and astringin were synthesized from inexpensive chrysin and piceid in short steps. The key feature of these syntheses is site-selective transformation. The target molecules were obtained in 27 and 62% yields from the starting materials, respectively.

Topics: Acetylation; Chemistry Techniques, Synthetic; Flavanones; Flavonoids; Glucosides; Humans; Molecular Structure; Stereoisomerism; Stilbenes

Enzymatic conversion of natural glycosides to their corresponding hydroxylated products using cytochromes P450 has significant advantages over synthetic chemistry and even enzyme-catalyzed glycosylation of chemicals. At present, the basic strategy for making glycosides of stilbenoid compounds is to use the glycosylation activity of enzymes, such as glycosyltransferases. Here, an efficient synthesis of a valuable (E)-astringin, a piceatannol glucoside, was developed using CYP102A1 via the highly regioselective C-3' hydroxylation of polydatin, a resveratrol glucoside. (E)-astringin is a high added value compound found in plants and wine. Benzylic hydroxylation of polydatin provides an attractive route to (E)-astringin, a catechol product. Thus far, chemical and enzymatic methods of producing (E)-astringin have not been developed. In the present study, a set of CYP102A1 mutants from Bacillus megaterium was found to catalyze regioselective hydroxylation of polydatin at the C-3' position to generate an (E)-astringin, a piceatannol glucoside.

Topics: Amino Acid Substitution; Bacillus megaterium; Bacterial Proteins; Biocatalysis; Biotechnology; Cytochrome P-450 Enzyme System; Glucosides; Hydroxylation; Kinetics; Mutagenesis, Site-Directed; NADPH-Ferrihemoprotein Reductase; Protein Engineering; Stilbenes

Phenolic stilbene glucosides (astringin, isorhapontin, and piceid) and their aglycons commonly accumulate in the phloem of Norway spruce (Picea abies). However, current knowledge about the localization and accumulation of stilbenes within plant tissues and cells remains limited. Here, we used an innovative combination of novel microanalytical techniques to evaluate stilbenes in a frozen-hydrated condition (i.e. in planta) and a freeze-dried condition across phloem tissues. Semiquantitative time-of-flight secondary ion-mass spectrometry imaging in planta revealed that stilbenes were localized in axial parenchyma cells. Quantitative gas chromatography analysis showed the highest stilbene content in the middle of collapsed phloem with decreases toward the outer phloem. The same trend was detected for soluble sugar and water contents. The specimen water content may affect stilbene composition; the glucoside-to-aglycon ratio decreased slightly with decreases in water content. Phloem chemistry was correlated with three-dimensional structures of phloem as analyzed by microtomography. The outer phloem was characterized by a high volume of empty parenchyma, reduced ray volume, and a large number of axial parenchyma with porous vacuolar contents. Increasing porosity from the inner to the outer phloem was related to decreasing compactness of stilbenes and possible secondary oxidation or polymerization. Our results indicate that aging-dependent changes in phloem may reduce cell functioning, which affects the capacity of the phloem to store water and sugar, and may reduce the defense potential of stilbenes in the axial parenchyma. Our results highlight the power of using a combination of techniques to evaluate tissue- and cell-level mechanisms involved in plant secondary metabolite formation and metabolism.

Topics: Freeze Drying; Gas Chromatography-Mass Spectrometry; Glucosides; Imaging, Three-Dimensional; Microscopy, Electron, Scanning; Phloem; Picea; Spectrometry, Mass, Secondary Ion; Stilbenes; Water; X-Ray Microtomography

Stilbenes are valuable phenolic compounds that are synthesized in plants via the phenylpropanoid pathway where stilbene synthase (STS) directly catalyzes resveratrol or pinosylvin formation. Currently, there is a lack of information about the stilbene biosynthetic pathway in spruce (Picea). Resveratrol and piceatannol derivatives have been detected in the spruce bark, needles, and roots. We analyzed seasonal variation in stilbene spectrum and content in the needles of different ages of one tree of spruce Picea jezoensis. HPLC analysis revealed the presence of nine stilbenes: t- and cis-astringin, t- and cis-piceid, t- and cis-isorhapontin, and t-piceatannol were present in amounts of 0.01-6.07 mg/g of dry weight (DW), while t-isorhapontigenin and t-resveratrol were present in traces (0.001-0.312 μg/g DW). T-astringin prevailed over other stilbenoid compounds (66-86% of all stilbenes). The highest total stilbene content was detected in one-year-old needles collected in the autumn and spring (5.4-7.77 mg/g DW). We previously cloned and sequenced full-length cDNAs of the four STS transcripts (PjSTS1a, PjSTS1b, PjSTS2, and PjSTS3) of P. jezoensis. This study presents a detailed analysis of seasonal variations in PjSTS1a, 1b, 2, and 3 transcript levels in the needles of P. jezoensis of different ages using qRT-PCR. PjSTS1a and PjSTS1b transcription was higher in the needles collected in the autumn, spring, or summer than in the winter. PjSTS2 was actively transcribed in the needles of all ages collected in the winter, spring, and summer. PjSTS3 expression did not significantly change during the year and did not depend on the age of the needles. Therefore, the data show that high levels of the stilbene glucosides and PjSTS expression are present in the needles of P. jezoensis.

Topics: Acyltransferases; Glucosides; Phenols; Picea; Plant Bark; Plant Roots; Resveratrol; Stilbenes

This study aimed to develop viable enzymes for bioconversion of resveratrol-glucoside into resveratrol. Out of 13 bacterial strains tested, Lactobacillus kimchi JB301 could completely convert polydatin into resveratrol. The purified enzyme had an optimum temperature of 30-40°C and optimum pH of pH 5.0 against polydatin. This enzyme showed high substrate specificities towards different substrates in the following order: isorhaponticin>>polydatin>>mulberroside A>oxyresveratrol-3-O-glucoside. Additionally, it rarely hydrolyzed astringin and desoxyrhaponticin. Based on these catalytic specificities, we suggest this enzyme be named stilbene glucoside-specific β-glucosidase. Furthermore, polydatin extracts from Polygonum cuspidatum were successfully converted to resveratrol with a high yield (of over 99%). Stilbene glucoside-specific β-glucosidase is the first enzyme isolated from lactic acid bacteria capable of bio-converting various stilbene glucosides into stilbene.

Topics: Bacterial Proteins; beta-Glucosidase; Biotransformation; Disaccharides; Glucosides; Industrial Microbiology; Lactobacillus; Resveratrol; Stilbenes; Substrate Specificity

By means of the accurate computations based on the density functional theory, the relationships between the molecular structure and free radical scavenging activity have been studied for dimer of trans-4,4'-dihydroxystilbene, trans-resveratrol-3-O-glucuronide, glucosides: geometric stereoisomers of piceid, trans-astringin, trans-resveratrol-4'-O-beta-D-glucopyranoside and trans-resveratrol dimers: pallidol, geometric stereoisomers of epsilon-viniferin, stereoisomers of trans-delta-viniferin and trans-resveratrol trimer-gnetin H. Our results have shown that all oligomers, glucosides and trans-resveratrol-3-O-glucuronide exhibit stronger antioxidant activity than trans-resveratrol and that dimer of trans-4,4'-dihydroxystilbene is a stronger antioxidant than its monomer as well as that cis stereoisomers of piceid and epsilon-viniferin are weaker antioxidant than their trans stereoisomers. The homolytic bond dissociation enthalpy values calculated reveal the predominant H-transfer capacity of the OH groups in the trans-stilbene moiety. The hydrogen atom transfer mechanism of free radicals scavenging by the compounds studied is proved more preferable than the single-electron transfer mechanism in the mediums investigated. All the above-mentioned compounds have been proved to have significantly higher ability to electron donation in water medium than in the gas phase. The experimental observations are satisfactorily explained by the results obtained.

Topics: Dimerization; Free Radical Scavengers; Glucose; Glucosides; Glucuronides; Models, Molecular; Molecular Conformation; Quantitative Structure-Activity Relationship; Quantum Theory; Resveratrol; Stereoisomerism; Stilbenes

The roots of three varieties of Polygonum cuspidatum were analyzed for resveratrol and its analogs. The powder of the dried roots was extracted with aqueous ethanol (60% v/v) and the extracts obtained were analyzed using RP HPLC with coulometric detection. A simple HPLC method with a multichannel CoulArray detector was developed for the determination of four stilbenes: resveratrol, its glucoside piceid, piceatannol, and its glucoside astringin. Analyses were carried out on a LiChrospher C18 (125 x 4.6 mm id, particle size 5 microm) column with a mobile phase of ammonium acetate (pH 3) and ACN in gradient mode. Four compounds were monitored by a CoulArray electrochemical detector. Potentials of eight electrochemical cells in series were set in the range of 200-900 mV. Optimization of the mobile phase pH was performed. Calibration curves showed good linearity with correlation coefficients (r(2))--more than 0.9975.

Topics: Chromatography, High Pressure Liquid; Electrochemistry; Fallopia japonica; Glucosides; Hydrogen-Ion Concentration; Plant Roots; Resveratrol; Stilbenes

Phenolics from grapes and wines can play a role against oxidation and development of atherosclerosis. Stilbenes have been shown to protect lipoproteins from oxidative damage and to have cancer chemopreventive activity. We describe a method for the direct determination of stilbenes in several red wines using high-performance liquid chromatography with UV detection. In a survey of 12 commercial wines from the south of Brazil (Rio Grande del Sul), levels of delta-viniferin are reported for the first time in different varieties of red wines. Brazilian red wine contains trans-astringin, trans-piceid, trans-resveratrol, cis-resveratrol (in high quantity: 5 times more than the trans form), epsilon-viniferin, and a compound isolated for the first time in wine, trans-delta-viniferin. Isolation and identification of delta-viniferin was achieved by NMR after extraction and fractionation of red wine phenolics. delta-Viniferin contributes, as well as cis-resveratrol and trans-piceid, to a significant proportion of stilbenes in wine dietary intake, particularly with Merlot varieties containing an average level of 10 mg/L for delta-viniferin, 15 mg/L for cis-resveratrol, and 13 mg/L for trans-piceid. The total stilbene intake from wine origin was estimated for the Brazilian population as 5.3 mg/day per person (on the basis of a regular wine consumption of 160 mL/day). delta-Viniferin can contribute to around 20% of total stilbenes in wine (average of 6.4 mg/L in red Brazilian wines). It would be important in the future to investigate the origins of the differences in wine stilbene levels in relation to the vine varieties, and the bioavailability of the newly extracted stilbene delta-viniferin in plasma after consumption of different types of wines.

Topics: Benzofurans; Brazil; Chromatography, High Pressure Liquid; Glucosides; Magnetic Resonance Spectroscopy; Resorcinols; Resveratrol; Stilbenes; Wine