Extraction of flavan-3-ols from grape seed and skin into wine using simulated maceration

Simulated maceration assays were carried out in wine model systems using increasing ethanol percentages from 0 to 12.5%, in order to study the extraction of flavan-3-ol monomers and oligomers from grape skins and seeds. The amount of flavan-3-ols transferred to the solutions improves with the increase in the alcohol percentage, although flavanols were much more readily released from grape skins than from seeds. Maximum release of flavanols from the skins is reached after 24 h of maceration in 12.5% ethanol, whereas long maceration and higher ethanol percentages were required for extraction from the seeds, from which maximum flavanol extraction was observed after 2-3 weeks of maceration. Thus, the length of the maceration not only had an influence in the total levels of flavanols reached in the wines, but also in their qualitative composition. The contribution of the seeds to the flavanol composition of the model wines was found to range from about 40% at 24 h of maceration in 12.5% ethanol to as high as 90% after 3 weeks. Gallocatechin was the major flavanol contributed by the skins and catechin by the seeds of the grape variety used (Vitis vinifera cv. Viura). Flavanol extraction was also followed during winemaking of commercial red wines, reaching similar conclusions to that obtained from the model assays.     

Hydrolyzed Tannins from Geranium pusillum

The polyphenolic compound 1-O-galloyl-3,6-hexahydroxybiphenyl-D-galactopyranoside (pusilagin) was isolated from the aerial part. The tannin structure was established using acid hydrolysis and IR, PMR, and ¹³C NMR spectral methods.     

基质辅助激光解吸附飞行时间质谱分析缩合单宁的阳离子化问题

以单价金属离子Cs 和Na 作为离子化试剂,对3种缩合单宁进行基质辅助激光解吸附飞行时间(MALD I-TOF)质谱分析。加入Na 作为阳离子化试剂,能得到较高质量的质谱图。但由于实验通道中几乎不可能完全去除的K 的干扰而会高估棓儿茶酚/表棓儿茶酚单元的组成比例,从而影响对棓儿茶酚/表棓儿茶酚单元存在与否的判断;选择Cs 作为阳离子化试剂可以避免此问题,但在复杂的缩合单宁分析中,同样因为杂质离子Na 和K 的干扰而使得质谱图变得更复杂;未去离子处理直接对缩合单宁进行MALD I-TOF质谱分析与去离子并加入Cs 的处理比去离子并加入Na 能检测到更高聚合度的高聚物,检测到离子峰强度最高的聚合物随离子不同而不同。     

Determination of proanthocyanidin A2 content in phenolic polymer isolates by reversed-phase high-performance liquid chromatography

This article summarizes the development of an analytical method for the determination of proanthocyanidin (PAC) A2 in phenolic polymer isolates following acid-catalyzed degradation in the presence of excess phloroglucinol. Isolates from concentrated cranberry juice (CCJ) were extensively characterized and molar extinction coefficients were determined for the terminal A2 and phloroglucinol adduct of the extension A2 unit. Peanuts were also found to contain both extension and terminal A-type PACs and therefore a total peanut system (TPS) was chosen to test the effectiveness of the HPLC method that was developed with the CCJ system. Kinetic studies were conducted and reaction conditions were optimized for the A2 units in both CCJ and TPS. The optimized method provides quantitative and reproducible information on the A2 content of proanthocyanidin isolates.     

Purification,Characterization and N‐terminal Sequence Analysis of Betel Leaf (Piper betle) Invertase

The present study is the first report describing the purification, enzymatic properties and N‐terminal amino acid sequence of a native invertase in betel leaf. The invertase was purified as a monomeric glycoprotein of molecular mass (Mr) 68 kDa. The enzyme was capable to attack β‐fructofuranoside linkages from the fructose end of sucrose, raffinose and stachyose indicating it as an authentic β‐D‐fructofuranosidase with high specificity for sucrose (Km 4.83 mM). The maximum activity was detected at pH 5.2 and 37 °C. Glucose and fructose showed typical inhibitory effect on the enzyme activity where as lectin was found to be effective activators of the enzyme. Significant inhibition by heavy metal ion Hg²⁺ and sulfhydryl group modifying agents suggesting that free sulfhydryl group containing amino acid, cysteine is necessary for the catalytic activity of the invertase. A BLAST search of the N‐terminal amino acid sequence of betel leaf invertase showed significant homology with the homologous invertases in database.     

An Extraction Method for Obtaining the Maximum Non-Anthocyanin Phenolics from Grape Berry Skins

To obtain maximum non-anthocyanin phenolics from grape skins, various extraction conditions were evaluated according to the amounts of 8 non-anthocyanin phenolics. The result showed that the optimal extraction was performed in ethyl acetate solution at 25°C, with liquid/solid ratio of 10:1 (ml/g) and for 30 min. On this basis, the non-anthocyanin extracts from two red and two white grape cultivars were analyzed using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC- MS/MS), and twenty-four compounds were qualified and simultaneously quantified, which indicated that the present extraction method was suitable for the study of non-anthocyanin in grape skins.     

Syntheses of tetrahydropyridin-3-ol and tetrahydroazepin-3-ol from a chiral aziridine-2-carboxylate

A method for the stereoselective preparation of 1,2,3,6-tetrahydropyridin-3-ols and 2,3,4,7-tetrahydro-1H-azepin-3-ols, potentially versatile intermediates in the asymmetric synthesis of various piperidine alkaloids and azasugars, has been developed. The routes start with a readily available optically pure aziridine-2-carboxylate. The design strategy relies on four key transformations involving (1) stereoselective reduction of an acyl-aziridine intermediate derived from the aziridine-2-carboxylate, (2) regioselective aziridine ring opening, (3) N-allylation, and (4) ring-closing metathesis. The method developed in this investigation provides ready access to stereochemically defined and highly functionalized 3-hydroxy-substituted tetrahydropyridines and tetrahydroazepines.     

18-Succinyloxyabieta-8,11,13-triene as a new component from green shoots of the Siberian fir

A new diterpene derivative, 18-succinyloxyabieta-8,11,13-triene, was isolated from the acidic fraction of the extract from wood greens of a Siberian fir. The chemical structure of the molecule was established on the basis of spectroscopy and confirmed by partial synthesis from abieta-8,11,13-trien-18-ol. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1697–1698, July, 2005.     

双金属改性MCM-41催化甲醛与异丁烯Prins缩合反应

通过研磨法制备了一系列不同金属负载的MCM-41催化剂,考察了单一金属及双金属负载催化剂对甲醛与异丁烯Prins缩合制备3-甲基-3-丁烯-1-醇(MBO)反应性能的影响,筛选出最佳的双金属Cu-Al负载催化剂.利用XRD、 NH_3-TPD、 N_2吸附、 UV-vis等表征手段对双金属改性前后催化剂的结构和酸性进行了深入分析,探究了其物质的量比例和协同作用对Prins反应性能的影响.结果表明,在温度200℃, n(异丁烯)/n(甲醛)=7,反应4 h的适宜条件下, Cu-Al(1∶1)/MCM-41对甲醛的转化率为100%, MBO产率高达98%,高于单一金属负载的催化剂. NH_3-TPD表征发现Cu-Al双金属负载催化剂具有适当的酸量和适宜的酸强度,可以提高MBO的产率.Cu-Al(1∶1)/MCM-41催化剂具有一定的再生性能,连续3次再生后催化剂的比表面积和孔容明显降低,催化剂活性中心聚集导致酸量尤其是中强酸和强酸量减少是反应活性下降的主要原因.     

Two new promelacacinidin dimers,including a novel flavanone-flavanol dimer characterized by a unique C(3)-C(4) linkage,from the heartwood of <Emphasis Type="Italic">Acacia nigrescens</Emphasis>

Two new promelacacinidin biflavonoids, mesquitol-(4α,5)-epimesquitol-4β-ol and a 3′,4′,7,8-tetrahydroxyflavanone(3,4)-ent-epimesquitol, were isolated among others from the heartwood of Acacia nigrescens. The flavanone derived dimer, characterized by a unique C(3) to C(4) bridge, which links the monomers via two stereogenic and sp³ hybridized C-atoms, is the prototype of a new subgroup of the flavonoid family. Assessment of the absolute configuration of all five stereogenic centers of this novel flavanone-derived biflavonoid was achieved by correlating the chiroptical properties of the benzoyl chromophore to the absolute configuration of C(2) of the flavanone moiety and hence the absolute stereochemistry of the other four chiral centers. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 437–441, September–October, 2007. Dedicated to Prof. E. Malan, who initiated and supervised this research project, for a noteworthy contribution in the flavonoid field, and who has since retired.     

Isocalamenenes from the Liverwort Bazzania tridens

Four new sesquiterpenoids, 1,4-trans-6-hydroxyisocalamenene; 1,4-trans-6-methoxyisocalamenene; (+)-aristol-9-en- 12β-ol, and eudesm-4(15)-en-6β-acetoxy-7β-ol, were isolated from Bazzania tridens, a liverwort species. Their structures were identified by means of spectroscopic methods. The two isocalamenenes are derived from a methyl rearrangement of the calamenene skeleton.     

Synthesis of Drim-9(11)-en-8α- and -8β-ols from Drimenol

Drim-9(11)-en-8α-ol and drim-9(11)-en-8β-ol were synthesized in six steps from drimenol. Drimenol was oxidized by P₂O₅ and DMSO to drimenal, which isomerized with p-TsOH into isodrimenal. Isodrimenal was reduced by NaBH₄ into isodrimenol, epoxidation of which by m-CPBA gave a mixture (3.4:1) of α- and β-epoxyisodrimenols. These reacted with tosyl chloride in Py to give a mixture of α- and β-epoxyisodrimenol tosylates. Treatment of the tosylate mixture with KI and then Ph₃P produced a mixture of drim-9(11)-en-8α- and -8β-ols that was separated chromatographically. The overall yield was ∼26%.__________Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 152–155, March–April, 2005.     

One-pot synthesis of 1-monosubstituted-1, 2, 3-triazoles from 2-methyl-3-butyn-2-ol

An efficient method for the synthesis of 1-monosubstituted-1, 2, 3-triazoles from 2-methyl-3-butyn-2-ol under copper catalyst conditions has been developed through a one-step one-pot sequence. This method provides a concise and efficient pathway to synthesize 1-monosubstituted-1, 2, 3-triazole derivatives in good to excellent yields.     

A new methylene bisflavan-3-ol from the branches and leaves of Potentilla fruticosa

Abstract

Dasiphora fruticosa L. (Rosaceae), also known as Potentilla fruticosa L. (syn.), is a hardy deciduous shrub widely distributed in the north temperate regions of the world. Three methylene bisflavan-3-ols (1-3), together with a procyanidin dimer, (-)-afzelechin-(4α→8)-(-)-afzelechin (4) were isolated for the first time from the branches and leaves of the titled plant, in addition to 11 known compounds (5-15). Their structures were elucidated by means of extensive spectroscopic analysis and by comparison with data reported in the literatures. Methylene 6,8-bis(7-O-glucosyl) catechin (1) was determined to be a new dimeric flavan-3-ol glycoside through a methylene linkage between C-8 and C-8 of two units. At a concentration of 128?μg/mL, the known compounds 9 – 13 exhibited antibacterial activities on Escherichia coli, Staphylococcus aureus subsp. aureus, Salmonella enterica subsp. enterica, and Pseudomonas aeruginosa. Compound 12 also showed certain glucose uptake stimulating activity.     

Seasonal Variability of Volatilome from Dictyota dichotoma

Dictyotaceae, the large family of brown algae with the genus Dictyota as the richest one among them, produce a significant number of secondary metabolites, like diterpenes. The aim of this study was to investigate the variations in the composition of the volatile organic compounds (VOCs) of the brown alga Dictyota dichotoma collected from the Adriatic Sea. For the first time, both seasonal changes and the impact of air drying were examined. Headspace solid-phase microextraction (HS-SPME) on two fibres with different polarities and hydrodistillation (HD), followed by gas chromatography and mass spectrometry (GC-MS) analysis, was performed on both fresh (FrDd) and air-dried (DrDd) D. dichotoma. The major compounds of HS-FrDd were pentadecane and oct-1-en-3-ol. The percentage of pentadecane in HS-DrDd was increased up to 7.8 times in comparison with HS-FrDd. Principal component analysis (PCA) identified differences between the variability of data among fresh and dried samples over months and clearly dissociated the fresh May samples from the others in the HS-SPME results. The most abundant group of VOCs in HD were terpenes, with diterpenes isopachydictyol A and cembra-4,7,11,15-tetraen-3-ol as the major compounds. Diterpene pachydictyol A was also found and among sesquiterpenes and gleenol was the most abundant. Based on the dominant compound analyses, the PCA showed distinct separation of the fresh and dried samples, indicating similarities between the samples and allowing the establishment of typical VOCs significant for the chemotaxonomy of D. dichotoma.     

Synthesis, structural and crystallographic study of some carbamates derived from 9-methyl-9-azabicyclo[3.3.1]nonan-3α-ol

A series of benzimidazole, thiazole and benzothiazole carbamates derived from 9-methyl-9-azabicyclo[3.3.1]nonan-3α-ol was synthesized and studied by ¹H, ¹³C, 2D NMR and IR spectroscopy. To assist in the interpretation of the spectroscopic data, the crystal structure of 3 (9-methyl-9-azabicyclo[3.3.1]nonan-3α-yl 2-amino-1H-benzimidazole-1-carboxilate) was determined by X-ray diffraction. It has been found that 1-carbamates and 2-carbamates can be obtained in the case of the benzimidazole derivatives. The benzimidazole-1-carbamates are obtained in higher yields (41, 38%) than the benzimidazole-2-carbamates (3, 9%). The compounds studied displayed in CDCl₃ solution a preferred chair–boat conformation with the substituted ring in a distorted boat form and the N–CH₃ substituent in an axial position with respect to the chair piperidine ring. This conformation is similar to that determined by X-Ray diffraction for compound 3.     

Stereospecific synthesis of 11E-tetradecenal, 11E-tetradecen-1-ol, and its acetate, pheromone components of insects ofLepidoptera order, from 10-undecenoic acid

A regio- and stereospecific synthesis of 11E-tetradecen-1-ol and its derivatives, which are pheromone components of many insect species ofLepidoptera order, by means of a reaction of methylmagnesium cuprate reagent with 1,12-tridecadien-3-yl acetate by theS _N2′ mechanism, was carried out. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1074–1075, May, 1997.     

An expeditious approach to access 2-arylimidazo[1,2-a]pyridin-3-ol from 2-amino pyridine through a novel Petasis based cascade reaction

An expeditious cascade protocol for the synthesis of functionalized imidazo[1,2-a]pyridin-3-ols was developed based on the Petasis reaction. With the availability of commercial reagents and high efficiency in expanding molecule diversity, this methodology is superior to the existing procedures for the synthesis of imidazo-pyridin-3-ol analogues.     

Cucurbitadienol synthase, the first committed enzyme for cucurbitacin biosynthesis, is a distinct enzyme from cycloartenol synthase for phytosterol biosynthesis

Three oxidosqualene cyclase (OSC) cDNAs (CPX, CPQ, CPR) were cloned from seedlings of Cucurbita pepo by homology based PCR method. Their open reading frames were expressed in lanosterol synthase deficient (erg7) Saccharomyces cerevisiae strain GIL77. Analyses of in vitro enzyme activities and in vivo accumulated products in the transformants demonstrated that CPQ and CPX encode cucurbitadienol and cycloartenol synthases, respectively. These results indicated the presence of distinct OSCs for cycloartenol and cucurbitadienol synthesis in this plant.     

Isolation and antiproliferative activity of triterpenoids and fatty acids from the leaves and stem of Turraea vogelii Hook. f. ex benth

Chloroform extract from the leaves of Turraea vogelii Hook f. ex Benth demonstrated cytotoxic activity against a chronic myelogenous leukemia cell, K-562 with IC₅₀ of 14.27 μg/mL, while chloroform, ethyl acetate and methanol extracts from the stem of the plant inhibited K-562 cells growth with IC₅₀ of 19.50, 24.10 and 85.40 μg/mL respectively. Bioactive chloroform extract of Turraea vogelii leaves affords two triterpenoids: oleana-12,15,20-trien-3β-ol (1), and oleana-11,13-dien-3β,16α,28-triol (2), with six fatty esters, ethyl hexaeicos-5-enoate (3), 3-hydroxy-1,2,3-propanetriyltris(tetadecanoate) (4), 1,2,3-propanetriyl(7Z,7′Z,7′′Z)tris(-7-hexadecenoate) (5), 1,2,3-propanetriyl(5Z,5′Z,5′′Z)tris(-5-hexadecenoate) (6), 1,2,3-propanetriyltris(octadecanoate) (7), and 2β-hydroxymethyl tetraeicosanoate (8). Tetradecane (9), four fatty acids: hexadecanoic acid (10), tetradecanoic acid (11), (Z)-9-eicosenoic acid (12), and ethyl tetradec-7-enoate (13) were isolated from chloroform extract of Turraea vogelii stem. 1,2,3-propanetriyltris(heptadecanoate) (14), (Z)-9-octadecenoic acid (15) and (Z)-7-tetradecenoic acid (16) were isolated from ethyl acetate extract while (Z)-5-pentadecenoic acid (17) was obtained from methanol extract of the plant stem. Compounds 1, 2, 5, 6, 11, 12, 15, 16 and 17 exhibited pronounced antiproliferative activity against K-562 cell lines.