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1.
Rapid fractionation of grape seed proanthocyanidins.   总被引：5，自引：0，他引：5  
A rapid method that permits separation of grape seed proanthocyanidins according to their polymerization degrees has been developed. This method was based on liquid/liquid extraction and relative solubility of these compounds in different solvents (water, ethyle acetate, methanol, and chloroform). The different fractions obtained were then analyzed by various HPLC techniques (normal phase, reversed phase after thiolysis, and gel permeation) to determine their mean degree of polymerization (DP) and molecular weight profiles. Results show that this method can be used on a preparative scale to separate these polymers according to their sizes.  相似文献   

2.
Monomeric and oligomeric procyanidins present in cocoa and chocolate were separated and identified using a modified normal-phase high-performance liquid chromatography (HPLC) method coupled with on-line mass spectrometry (MS) analysis using an atmospheric pressure ionization electrospray chamber. The chromatographic separation was achieved using a silica stationary phase in combination with a gradient ascending in polarity. This qualitative report confirms the presence of a complex series of procyanidins in raw cocoa and certain chocolates using HPLC/MS techniques. Although both cocoa and chocolate contained monomeric and oligomeric procyanidin units 2-10, only use of negative mode provided MS data for the higher oligomers (i.e., >pentamer). Application of this method for qualitative analysis of proanthocyanidins in other food products and confirmation of this method as a reliable quantitative tool for determining levels of procyanidins in cocoa, chocolate, and other food products are currently being investigated.  相似文献   

3.
Research in the field of procyanidins is always hindered by the lack of procyanidin standards, and the preparation of procyanidins, especially in large scale, remains difficult and time-consuming. Commercial sources of procyanidin standards are scarce. In this study, a rapid preparation method of procyanidins by using low-pressure column chromatography was developed. Procyanidins in Granny Smith apples were extracted with boiled water and purified on an ADS-17 macroporous resin column to obtain a Granny Smith apple procyanidin extract (GSE). GSE was fractionated according to its degree of polymerization on a Toyopearl TSK HW-40s column. Procyanidins B2 (epicatechin-(4beta-8)-epicatechin) and C1 (epicatechin-(4beta-8)-epicatechin-(4beta-8)-epicatechin) were prepared without HPLC separation. Oligomeric procyanidins from Granny Smith apples were also identified by liquid chromatography-electrospray ionization-mass spectrometry.  相似文献   

4.
Procyanidin fractions from apple were separated according to the degree of polymerization using normal phase chromatography. Evaluation of physiological functionalities of procyanidins requires individual structural determination. However, it is difficult to elucidate the structure of procyanidins, in particular those with (+)-epicatechin (1) or (-)-catechin (2) units, and determine whether the interflavanoid bonds are 4beta-->8 or 4beta-->6 without cleavage and acetylation. Structural determination used LC-MS and low-temperature NMR. Nine procyanidins were separated by preparative HPLC consisting of three well-known procyanidins [procyanidin B1 (3), procyanidin B2 (4), and procyanidin C1 (5)] and six new procyanidins [epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-catechin (6); epicatechin-(4beta-->6)-epicatechin-(4beta-->8)-catechin (7); epicatechin-(4beta-->6)-epicatechin-(4beta-->8)-epicatechin (8); epicatechin-(4beta-->8)-epicatechin-(4beta-->6)-catechin (9); epicatechin-(4beta-->8)-epicatechin-(4beta-->6)-epicatechin (10); and epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin (11)]. Compounds 6-11 were detected for the first time as apple constituents.  相似文献   

5.
The effects of apple polyphenols on melanogenesis in B16 mouse melanoma cells were investigated. The inhibitory effect of apple polyphenols was stronger than that of arbutin or kojic acid. Three polyphenol fractions (phenolic acid derivatives, procyanidins and other flavonoids) were isolated, and the procyanidins were fractionated according to the degree of polymerization using normal-phase chromatography. The procyanidin trimer-to-pentamer fractions were found to have the most pronounced effect on melanogenesis. Furthermore, each procyanidin fraction inhibited mushroom tyrosinase. No correlation between the degree of procyanidin polymerization and tyrosinase inhibitory activity was observed. Nevertheless, these observations suggest that procyanidins are effective inhibitors of tyrosinase.  相似文献   

6.
Inhibitory effects of apple polyphenol extract (AP) and procyanidin contained in AP on in vitro pancreatic lipase activity and in vivo triglyceride absorption in mice and humans were examined. AP and procyanidin considerably inhibited in vitro pancreatic lipase activity. However, polyphenols, except for procyanidin, in AP (i.e., catechins, chalcones, and phenol carboxylic acids) showed weak inhibitory activities on pancreatic lipase. Procyanidins separated by normal-phase chromatography according to the degree of polymerization were also examined. Inhibitory effects of procyanidins increased according to the degree of polymerization from dimer to pentamer. On the other hand, pentamer or greater procyanidins showed maximal inhibitory effects on pancreatic lipase. These results suggested that with respect to in vitro pancreatic lipase inhibition, the degree of polymerization was an important factor and oligomeric procyanidin mainly contributed. Next, we performed a triglyceride tolerance test in mice and humans. Simultaneous ingestion of AP and triglyceride significantly inhibited an increase of plasma triglyceride levels in both models. These results suggested that the oligomeric procyanidins contained in AP inhibited triglyceride absorption by inhibiting pancreatic lipase activity in mice and humans.  相似文献   

7.
Concentrations of the main dimeric and trimeric procyanidins (PC) and their monomeric constitutive units catechin (CT) and epicatechin (EC) were determined in food samples by using reversed phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (RP-HPLC-ESI-MS/MS). In a first step, 12 PCs (PC B1, B2, B3, B4, B5, B6, B7, B8, C1, C2, and A2 and cinnamtannin B1), of which most are not commercially available, were isolated from plant materials or synthesized and purified by a combination of column chromatographic separation techniques with different stationary phases. These PCs in combination with CT and EC were used as standard substances for identification and quantification during the following screening of food samples by RP-HPLC-ESI-MS/MS analysis. The main focus of the newly developed RP-HPLC-ESI-MS/MS method is the compensation of matrix effects by using the echo-peak technique simulating internal standard injection. The suitability of this new method was demonstrated by the determination of recovery rates being 90% or higher. Use of this method allowed the determination of patterns and concentrations of PCs in 55 food samples.  相似文献   

8.
The polymeric procyanidins were fractionated from lowbush blueberry on a Sephadex LH-20 column. The degree of polymerization (DP) for the polymers was determined by thiolysis to be in a range of 19.9 to 114.1. Normal-phase HPLC analysis indicated that the polymeric procyanidins did not contain oligomeric procyanidins with DP < 10. The polymers eluted as a single peak at the end of the chromatogram. The normal-phase HPLC gradient was modified to improve the separation of procyanidin monomers through decamers and to elute all the polymers beyond those as a distinct peak. Monomers through decamers were quantified individually. All the polymers (DP > 10) were quantified using a mixture of purified polymers as an external standard. Polymers were found to be the dominant procyanidins in brown sorghum bran, cranberry, and blueberry. Thiolysis of the polymer peaks indicated that epicatechin was present as extension units in these foods, however, the composition of terminal units varied considerably between catechin and epicatechin, or an A-type dimer linkage in the case of cranberry.  相似文献   

9.
The soil quality index (SQI) for cacao cropping systems was developed to meet the nutritional criteria of the crop, the environmental safety of the cropping sites and the increasing demand for the production and quality of cocoa. Available water function (AWF), root growth function (RGF), mineral nutrition of plants function (MNF) and environmental safety function (ESF) for potentially toxic elements were included in the additive model of SQI for cacao cropping systems. In this study, over 66% of the cacao fields cropping sites were classified as regular SQI with a range of scores between 0.42 and 0.61. The field cropping site with the highest score (0.73) characterized as typic Alitic Red-Yellow Argisol was rated with high SQI. In contrast, the field cropping sites characterized as abrupt Cohesive Dystrophic Red-Yellow Argisol (0.29), typic Dystrophic Haplic Cambisol (0.39), and latosolic Dystrophic Yellow Argisol (0.40) were rated with low SQI. MNF and AWF were the functions that most contributed to the increase or decrease of SQI scores. The SQI adapted expressed the agro-environmental reality of cacao cropping systems of Bahia, Brazil, and this could be a versatile tool to subsidize the adequate soil management of cacao plantations around the world.  相似文献   

10.
In this study, we investigated the absorption of apple procyanidins, namely, apple condensed tannins (ACTs), in rats using the Porter method and high-performance liquid chromatography/tandem mass spectrometry. The apple procyanidin concentrations in the rat plasma reached a maximum 2 h after administration and decreased thereafter. To investigate the limits of the absorption of apple procyanidins in the polymerization degree, we administered the procyanidin oligomer fraction, which was separated from ACT using normal-phase chromatography according to the degree of polymerization. Procyanidins from each dimer to pentamer group were detected in the plasma by the Porter method. Moreover, by the study using reconstituted procyanidins, polymeric procyanidins influenced the absorption of procyanidin oligomers. These results suggest that ACTs are absorbed and directly involved in physiological functions in the rats.  相似文献   

11.
Procyanidins, as important secondary plant metabolites in fruits, berries, and beverages such as cacao and tea, are supposed to have positive health impacts, although their bioavailability is yet not clear. One important aspect for bioavailability is intestinal metabolism. The investigation of the microbial catabolism of A-type procyanidins is of great importance due to their more complex structure in comparison to B-type procyanidins. A-type procyanidins exhibit an additional ether linkage between the flavan-3-ol monomers. In this study two A-type procyanidins, procyanidin A2 and cinnamtannin B1, were incubated in the pig cecum model to mimic the degradation caused by the microbiota. Both A-type procyanidins were degraded by the microbiota. Procyanidin A2 as a dimer was degraded by about 80% and cinnamtannin B1 as a trimer by about 40% within 8 h of incubation. Hydroxylated phenolic compounds were quantified as degradation products. In addition, two yet unknown catabolites were identified, and the structures were elucidated by Fourier transform mass spectrometry.  相似文献   

12.
We investigated the effect of polyphenols derived from cacao liquor on the mutagenic action of heterocyclic amines (HCAs) in vitro and ex vivo. In the Ames test, the cacao liquor polyphenols showed antimutagenic effects in bacteria treated with HCA in the presence of an S-9 mixture; however, they showed less efficacy than quercetin. On the other hand, the cacao liquor polyphenols showed potent antimutagenic activity in bacteria treated with activated forms of HCA, compared with quercetin. We also evaluated the effect of these compounds on enzymatic activation of HCA. They weakly suppressed the production of activated HCA. In the host-mediated assay in mice, a method used to estimate the potential carcinogenicity of chemicals ex vivo, oral administration of the cacao liquor polyphenols, reduced the number of colonies of revertant bacteria recovered from the liver. These data suggest that the cacao liquor polyphenols have an antimutagenic effect not only in vitro, but also ex vivo.  相似文献   

13.
Components of green tea ( Camellia sinensis) have been of considerable interest in recent years because of their potential utility as pharmaceutical agents, particularly for their antioxidant and anticarcinogenic activity. Responding to the increasing scientific validation of numerous health benefits of tea, a comprehensive approach was adopted to carry out analysis for the quality assessment of flavonoids in tea samples of different origins. For this purpose, extraction, separation, and mass spectrometric parameters were optimized. Extraction methods evaluated include reflux extraction, a modified accelerated solvent extraction (ASE), namely, Aquasolv extraction, and microwave-assisted extraction (MAE) using different percentages of solvents. Separation was performed by a specifically developed reversed phase high-performance liquid chromatography (RP-HPLC) method using different C18 and C8 stationary phases. Optimization of extraction techniques clearly proved the performance of MAE, which delivered highest yields in a very short time. Additionally, the comparison with Aquasolv extraction provided new insights, as variations in quantified amounts of target compounds between the extracts could be explained on the basis of thermal degradation and epimerization phenomena. Especially the epimerization phenomenon for catechin/epicatechin oligomers, that is, of procyanidins P 2 and P 3, was observed for the first time. Finally, an optimized extraction and separation system was used for qualitative and quantitative investigations of compounds from different green tea samples from Ceylon (cultivated under biologically controlled conditions), Japan, India, and China as well as from one black tea sample from India.  相似文献   

14.
Approaches for the capillary gas chromatographic (GC) based analysis of intact plant stanyl esters in enriched foods were developed. Reference compounds were synthesized by enzyme-catalyzed transesterifications. Their identities were confirmed by means of mass spectrometry. Using a medium polar trifluoropropylmethyl polysiloxane stationary phase, long-chain plant stanyl esters could be separated according to their stanol moieties and their fatty acid chains. Thermal degradation during GC analysis was compensated by determining response factors; calibrations were performed for ten individual plant stanyl esters. For the analysis of low-fat products (skimmed milk drinking yogurts), the GC separation was combined with a "fast extraction" under acidic conditions. For fat-based foods (margarines), online coupled LC-GC offered an elegant and efficient way to avoid time-consuming sample preparation steps. The robust and rapid methods allow conclusions on both, the stanol profiles and the fatty acid moieties, and thus provide a basis for the authentication of this type of functional food ingredients.  相似文献   

15.
Five French cider apple varieties were compared on the basis of their detailed polyphenol profile in the cortex and in the juices. Among the factors studied, variety was the most important variability factor in fruits, whereas polyphenol profiles showed an overall stability from one year to another, and a limited decrease of polyphenol concentration was observed during the starch regression period of fruit maturation. In juices, procyanidins remained the preponderant polyphenol class with concentrations up to 2.4 g/L even in centrifuged juices. Compared to the fruits, the average degree of polymerization of procyanidins was significantly reduced in the juice. Centrifugation of the crude juice had only minor effects on the polyphenol composition. For one variety, highly polymerized procyanidins with average degrees of polymerization of 25 were shown to be soluble in the centrifuged juice at a concentration of close to 1.2 g/L. Oxygenation of the juices during processing resulted in a significant decrease of all classes of native polyphenols. Catechins and procyanidins were particularly affected by oxidation, whereas caffeoylquinic acid was partly preserved. The transfer of polyphenols after pressing was maximal for dihydrochalcones and minimal for procyanidins with extraction yield values close to 80 and 30%, respectively.  相似文献   

16.
The interactions between porcine pancreatic lipase (PL) and grape seed procyanidins were studied by an enzymatic assay, fluorescence quenching, nephelometry, and dynamic light scattering (DLS). An inhibitory effect of grape seed procyanidins on lipase hydrolytic activity was found. Both the inhibition of lipase activity by procyanidins and the respective quenching of intrinsic protein fluorescence increased with the average degree of polymerization of the tested procyanidins. The association between procyanidins and enzyme involves a specific interaction as inferred from the fluorescence assays despite not changing significantly the tertiary structure of the protein. For all tested procyanidins it was shown, both by DLS and by nephelometry, that an increase in aggregation occurs up to a stoichiometric maximum after which further procyanidin addition causes a decrease in aggregation of aggregates. The maximum size of aggregates was shown to be closely related to the maximum overall aggregation. It was also shown that the inhibition of enzyme activity is to a large extent independent of the formation of aggregates.  相似文献   

17.
Cacao (Theobroma cacao L.) is the main source for chocolate with an annual production of four million tons worldwide. This Neotropical tree crop was domesticated in Mesoamerica as far back as 3,000 years ago. Knowledge of genetic diversity and population structure in farmer varieties of cacao in the center of domestication is essential for sustainable production of fine-flavored cacao beans and contributes to in situ/on-farm conservation of farmer varieties. Based on 70 single nucleotide polymorphism markers, we analyzed 84 fine-flavored farmer varieties collected from traditional cacao farms in Honduras and Nicaragua. The study also included 31 clones from the international cacao collections to serve as references. The SNP based multilocus matching identified six synonymous groups, including 14 Criollo and two Amelonado varieties. A moderately high level of genetic diversity was observed in these farmer varieties, indicating the possibility to further explore intra-population variation and breed for fine-flavored cocoa. Multivariate analysis showed clustering of the 84 farmer accessions in five genetic groups: ancient Criollo, Amelonado, Trinitario (including Nicaragua Trinitario and Honduras Trinitario) and Upper Amazon Forastero (only one accession). The Honduras Trinitario differed from the Nicaragua Trinitario group. The clustering results largely supported the perceived classification of cacao by local farmers and researchers, which was mainly based on morphological traits. However, the well known traditional variety “Indio” in this region was identified as synonymous with Amelonado. Parentage analysis showed that the variety “Indio” (or Amelonado) contributed more to the Trinitario type farmer varieties, whereas ancient Criollo had less influence. The present study demonstrates the efficacy of using a small set of SNP makers for cacao germplasm characterization, and further depicts the diverse origins and parentage in farmer varieties from Mesoamerica. This information thus will be highly useful for conservation and utilization of cacao germplasm from this region.  相似文献   

18.
Cellulose-based chromatography for cellooligosaccharide production   总被引：5，自引：0，他引：5  
The potential of using cellulose stationary phases for the chromatographic fractionation of cellooligosaccharide preparations has been explored. The impetus for the work is the current interest in using cellooligosaccharides as functional nondigestible oligosaccharides in foods. The conceptual studies illustrate the potential of using ethanol-water mobile phases in conjunction with cellulose stationary phases for cellooligosaccharide fractionation. Cellooligosaccharide solubility in ethanol-water mixtures and their elution order from cellulose-based columns using ethanol-water mobile phases were shown to be in line with their degree of polymerization (DP), with the higher DP cellooligosaccharides being less soluble and having longer retention times. The retention volume for all COS increased with increased temperature. Both microcrystalline and fibrous cellulose preparations were shown to work as chromatographic stationary phases. The application experiments demonstrate the potential of using cellulose stationary phases for the cleanup and fractionation of cellooligosaccharide mixtures generated via acid-catalyzed hydrolysis of cellulose.  相似文献   

19.
A method was developed for the fractionation of grape (seed or skin) proanthocyanidins according to their degree of polymerization. After precipitation in chloroform/methanol (75:25, v/v), the grape proanthocyanidins were deposited onto an inert glass powder column and sequentially dissolved in several fractions by increasing proportions of methanol in the solvent. Each fraction from each proanthocyanidin source was quantified and characterized after acidic degradation with phenylmethanethiol (i.e., thiolysis). The comparison of data from total extract and successive fractions showed that a quantitative separation was achieved so that estimation of polymer size distribution in relation to other compositional characteristics (proportions of prodelphinidin units, galloylation rate) was thus possible. Mean degree of polymerization of separated proanthocyanidins ranged increasingly from 4.7 to 17.4 in seed (8.1 for total extract) and from 9.3 to 73.8 in skin (34.9 for total extract). The method proposed is very interesting for the study of grape proanthocyanidins according to their degree of polymerization because it gives both qualitative and quantitative information especially on the highly polymerized forms, which were not fractionated by previous techniques.  相似文献   

20.
Large-scale intensification of smallholder cacao management is currently affecting the agroforestry landscapes of Sulawesi (Indonesia), the world’s third largest cacao producer. Little is known about how this shift from diverse plantations to full-sun cacao will affect functionally important biodiversity within the agroecosystem, and how this is related to landscape-wide patterns in land-use and natural ecosystems. We recorded birds in 43 cacao plots differing in woody and herbaceous vegetation as well as distance to forest in two valleys around the Lore Lindu National Park in Central Sulawesi. Species richness of frugivores and nectarivores decreased with increasing distance to forest, whereas granivorous birds increased in richness. Forest specialists, but not habitat generalists, responded positively to forest edge proximity. Species richness of all functional groups except seed eaters increased at higher density of tall shade trees. Greater species richness of shade trees was associated with higher species richness of frugivores and nectarivores, while herbaceous vegetation did not have a strong impact on the avifauna. The positive effect of shade trees was independent of distance to forest. In conclusion, our study shows the relative importance of local and landscape effects on bird diversity with shade trees being critical for bird conservation in cacao agroforestry landscapes.  相似文献   

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