高聚原花青素降解技术研究进展

原花青素是一类广泛存在于自然界中的黄烷-3-醇类化合物,由于大多数从自然界获得的原花青素为带有苯环或长碳链的高聚原花青素,导致其生理活性较弱.通过降解,可以增强原花青素的生理活性以及应用范围.因此,高聚原花青素降解技术成为国内外研究的热点.本文详细整理了国内外有关原花青素高聚体降解技术的文献报道,对化学、生物以及物理降...     

不同品种葡萄枝蔓中原花青素含量及其活性的比较研究

以不同品种葡萄枝蔓为原料提取其中的原花青素并进行分离纯化,同时采用清除自由基的方法评价得到的高、低聚原花青素的抗氧化活性。结果表明：各品种葡萄枝蔓中原花青素的总含量为36.81～68.49 mg/g;其中,低聚原花青素的含量在9.75～16.87 mg/g之间,高聚原花青素含量在13.56～26.04 mg/g之间。各提取物的抗氧化活性研究表明,高、低聚原花青素都有较强的抗氧化活性。通过显著性分析发现,当原花青素质量浓度为0.02 mg/mL时,其对DPPH自由基的清除能力与葡萄枝蔓的品种有关,而对羟基自由基的清除能力与原花青素的聚合度有关;当质量浓度提高到0.05 mg/mL时,其对羟基自由基的清除能力也与葡萄枝蔓的品种有关。     

Sea buckthorn (Hippophae rhamnoides) proanthocyanidins inhibit in vitro enzymatic hydrolysis of protein

Abstract: Interactions of phenolics with other food constituents and digestive enzymes are likely to have interference with the digestion and bioavailability of food and phenolics. In this study the effect of sea buckthorn proanthocyanidins on in vitro digestion of protein was evaluated. Optimization of the extraction conditions showed that maximum recovery of sea buckthorn proanthocyanidins was obtained with acidified acetone; water mixture (60% to 70%, v/v). Crude proanthocyanidin extracts thus prepared were purified using sephadex gel column chromatography and their average degree of polymerization and the effects on enzymatic hydrolysis of bovine serum albumin as influenced by their protein precipitation capacities were studied. Average degree of polymerization of proanthocyanidins in berry pulp, kernel, seed coat, and leaves was 7.4, 5.6, 8.2, and 10.6, respectively. The EC50 values for the protein precipitation by the PA of berry pulp, kernel seed coat, and leaves were 44.2, 44.1, 65.8, and 39.8 μg, respectively. Relative enzymatic hydrolysis of the protein‐proanthocyanidin complexes was 44.1% to 60.3% for pepsin and 57.5% to 67.7% for trypsin. Interactions of sea buckthorn proanthocyanidins with food proteins and digestive enzymes might alter the protein digestibility and phenolic bioavailabilty.     

Effect of Polymerization on Antioxidant and Xanthine Oxidase Inhibitory Potential of Sea Buckthorn (H. rhamnoides) Proanthocyanidins

Abstract: Inhibitory potential of sea buckthorn (Hippophae rhamnoides L) seed proanthocyanidins against oxidative stress and xanthine oxidase activity was evaluated. Composition of antioxidant proanthocyanidins was profiled by analyzing the cleavage products obtained by the acid catalyzed hydrolysis in the presence of phloroglucinol. Catechin, epicatechin, gallocatechin, and epigallocatechin were found as the extension and terminal subunits of proanthocyanidins with an average degree of polymerization (ADP) of 14.7. Seed proanthocyanidins showed considerably high antioxidant and xanthine oxidase inhibitory potentials. Antioxidant and xanthine oxidase inhibitory capacity evaluation of proanthocyanidin fractions with varying ADP showed that proanthocyanidins with lower molecular size were more effective as superoxide anion (ADP ≤ 4.2) and hydroxyl radical (ADP ≤ 5.9) scavengers and xanthine oxidase (ADP ≤ 3.1) inhibitors. ADP of the studied proanthocyanidin fractions did not show significant influence on their DPPH and ABTS radical scavenging and ferric reduction capacities.     

Development of solid lipid microparticles loaded with a proanthocyanidin-rich cinnamon extract (Cinnamomum zeylanicum): Potential for increasing antioxidant content in functional foods for diabetic population

Cinnamon proanthocyanidins play an important role on the attenuation of complications associated to diabetes, but the daily ingestion of these compounds is not always satisfactory due to several aspects such as low stability and unpleasant taste. Thus, in the present study, a proanthocyanidin-rich cinnamon extract (Cinnamomum zeylanicum) was incorporated into solid lipid microparticles (SLMs) by spray chilling technique using vegetable fat as carrier. The microparticles were characterized with regard to their physical and chemical properties, morphology, proanthocyanidin stability and sensory properties. SLMs were spherical with a unimodal size distribution between 60 and 130 μm, and proanthocyanidins were highly stable in SLM stored for up to 90 days at 5, 25 and 37 °C. Moreover, SLMs were able to mask the bitter taste and astringent sensation of proanthocyanidins and other polyphenols from cinnamon extract. Taken together, these results show the potential of SLM loaded with cinnamon proanthocyanidins for improving functional properties in new foods.     

石榴皮原花青素的微波提取工艺及其稳定性研究

采用微波法提取野生石榴皮中的原花青素,同时考察光照、温度、金属离子、PH及食品添加剂对原花青素稳定性的影响。通过单因素试验和正交试验得出微波提取石榴皮原花青素的最佳工艺条件为：乙醇浓度80％、料液比1：50、提取温度65℃、微波功率500W、提取时间120s、提取2次,原花青素的得率为2．62％。稳定性研究表明,光照条件下色素稳定性较差;高温对色素有降解作用,60℃以下稳定性良好;pH值为5时色素稳定性好;金属离子Cu^2＋和Al^3＋对原花青素的稳定性影响显著;苯甲酸对原花青素稳定性影响显著。     

山楂原花青素对人肝癌SMMC-7721细胞增殖和凋亡的影响

目的：探讨山楂原花青素提取物、表儿茶素和原花青素B2对人肝癌SMMC-7721细胞增殖及凋亡的影响。方法：体外培养SMMC-7721细胞,噻唑蓝法检测不同质量浓度山楂原花青素对细胞增殖的影响;4’,6-二脒基-2-苯基吲哚染色法观察细胞凋亡,Western blot法检测细胞凋亡相关蛋白的表达;检测每组细胞中过氧化氢酶（catalase,CAT）、超氧化物歧化酶（superoxide dismutase,SOD）、谷胱甘肽过氧化物酶（glutathione peroxidase,GSH-Px）、Na＋K＋-ATP酶活力和丙二醛（malondialdehyde,MDA）含量。结果：山楂原花青素提取物、表儿茶素和原花青素B2呈时间和质量浓度依赖性地显著抑制SMMC-7721细胞的增殖（P＜0.05）,促进细胞凋亡;与对照组相比,SMMC-7721细胞中SOD、CAT、GSH-Px、Na＋K＋-ATP酶活力降低,MDA含量升高;细胞凋亡相关蛋白半胱天冬酶-8、半胱天冬酶-3、Bcl-2相关X蛋白表达量和多聚二磷酸腺苷核糖聚合酶片段化增加,Bcl-2表达量降低。结论：山楂原花青素可通过影响抗氧化酶活力和细胞凋亡相关蛋白来抑制SMMC-7721细胞增殖,促进细胞凋亡。     

Green tea catechins during food processing and storage: A review on stability and detection

Green tea catechins can undergo degradation, oxidation, epimerization and polymerization during food processing. Many factors could contribute to the chemical changes of green tea catechins, such as temperature, pH of the system, oxygen availability, the presence of metal ions as well as the ingredients added. Several detection methods have been developed for tea catechin analysis, which are largely based on liquid chromatography (LC) and capillary electrophoresis (CE) methods for getting a good separation, identification and quantification of the catechins. Stability of green tea catechins is also influenced by storage conditions such as temperature and relative humidity. The stability of each catechin varies in different food systems and products. Pseudo first-order kinetic model has been developed and validated for the epimerization and degradation of tea catechins in several food systems, whereas the rate constant of reaction kinetics followed Arrhenius equation.     

Changes in phenolic composition of Tinta Miúda red wines after 2 years of ageing in bottle: effect of winemaking technologies

The major phenolic compounds (catechins, oligomeric and polymeric proanthocyanidins, and anthocyanins) in Tinta Miúda red wines made by various winemaking technologies (i.e., fermentation with carbonic maceration, fermentation with stem contact and fermentation without stem contact) were analyzed after 2 years of ageing in bottle, and compared with the data on their younger state (i.e., at the time of bottling). The concentrations of all individual phenolic compounds analyzed were significantly changed and their degradation rates (percent of decrease) were highly dependent on the winemaking technology used. The degradation of anthocyanins was, in general, more remarkable than that of catechins and proanthocyanidins. Catechins and proanthocyanidins in carbonic maceration wine appeared more stable than in skin fermentation wines, during ageing in bottle.     

Degradation kinetics of grape skin and seed proanthocyanidins in a model wine system

Catechin (monomer), purified grape skin proanthocyanidin (polymer), and purified grape seed proanthocyanidin underwent monitored accelerated oxidation under continuous oxygenation and UV light, at a constant 20 °C. Compounds were dissolved in model wine solutions with (and without) catechol. Solutions were examined and then contrasted by absorbance measurements, phloroglucinolysis, and subsequent HPLC analysis. Oxidation of these monomers and polymers revealed significant colour changes (measurable increase in colour density). The presence of catechol increased the half-life of catechin, but the opposite was observed for total skin and seed proanthocyanidins. Skin and seed proanthocyanidin degradation half-life decreased with the addition of catechol. In general, based on second order rate reactions, total subunits of seed proanthocyanidin solutions degraded faster than that of skin proanthocyanidin solutions. As expected, there were decreases of measurable phenolics in both monomer and polymer solutions. Under the study conditions, flavanol monomer and polymer oxidation was chiefly dependant upon initial solution concentration.     

Changes in the color components and phenolic content of red wines from Vitis vinifera L. Cv. “Tempranillo” during vinification and aging

Changes in phenolics and color components during vinification and aging of Tempranillo wines were studied. Different phenolics display different diffusion into the must, and with the exception of proanthocyanidins and acetyl-glucoside anthocyanins, with maximum concentration at the end of postmaceration, the rest of the unacylated and coumarated anthocyanins, monomeric flavanols, and hydroxycinnamic acids reached their maximum at the end of alcoholic fermentation. This resulted in a significant increase in both wine color and stable color, mainly due to the formation of copigmentation complexes, although polymeric pigment formation was also important. Malolactic fermentation produced a significant decrease in flavonoid content while nonflavonoid concentrations were maintained, prompting a considerable loss in wine color, despite the dramatic increase in bisulfite-stable color. Wine oak aging did not produce any significant change in the studied parameters, while bottle aging reduced the level of monomeric anthocyanins and flavanols, and hydroxycinnamic acids. However, wine color remained stable due to a significant increase in stable color. Polymerization reactions of anthocyanins prevailed over pigment degradation reactions, and copigmentation was still relevant after 2 years of bottle aging.     

微波法萃取紫色甘薯皮原花青素工艺的研究

采用微波提取技术提取紫色甘薯皮中原花青素,研究微波控制条件对原花青素提取率的影响,并在单因素的基础上进行正交实验。研究结果表明:微波提取可以有效缩短原花青素提取时间并提高提取率,微波提取紫色甘薯皮原花青素的最佳提取工艺条件为以60%乙醇为提取液,微波功率600W、料液比为1∶14、微波作用时间140s、提取1次,在此条件下,原花青素的提取率为2.86%。     

Influence of skin maceration time on the proanthocyanidin content of red wines

This paper studies the influence of different maceration times (5, 10 and 20?days) during the elaboration of Monastrell, Syrah and Cabernet Sauvignon wines on the proanthocyanidin composition and sensory characteristics of the resulting wines. Significant differences were found between wines elaborated with different maceration times. The different maceration times affected the qualitative and quantitative proanthocyanidin composition of the resulting wines, the total proanthocyanidin content increasing with the maceration time. The percentage of skin-derived proanthocyanidins was always higher than that of seed-derived proanthocyanidins for all the maceration time assayed, although the contribution of seed proanthocyanidins to wine composition increased for the longest maceration time. However, the study also shows that differences exist between wines elaborated with the same maceration time but with different varieties, indicating the importance of two factors, the initial concentration of grape phenolic compounds and their extractability, on the final concentration of wine proanthocyanidins. In this way, the wines obtained from Syrah had the highest proanthocyanidin content compared with the corresponding wines from Cabernet Sauvignon or Monastrell, even though Syrah grapes presented the lowest proanthocyanidin content in skins and similar seed proanthocyanidin content to Cabernet and Monastrell grapes.     

Hypolipidemic effects of proanthocyanidins and their underlying biochemical and molecular mechanisms

Proanthocyanidins are the most abundant polyphenols in human diets. Epidemiological studies strongly suggest that proanthocyanidins protect against cardiovascular diseases. Despite the antioxidant and anti‐inflammatory properties of these flavonoids, one of the mechanisms by which proanthocyanidins exert their cardiovascular protection is improving lipid homeostasis. Animal studies demonstrate that proanthocyanidins reduce the plasma levels of atherogenic apolipoprotein B‐triglyceride‐rich lipoproteins and LDL‐cholesterol but increase antiatherogenic HDL‐cholesterol. The results in humans, however, are less clear. This review summarizes the results that have been published on plasma triglyceride, apolipoprotein B, HDL‐cholesterol and LDL‐cholesterol levels in humans and animal models in response to proanthocyanidin extracts and proanthocyanidin‐rich foods. The physiological processes and biochemical pathways that are related to lipid homeostasis and affected by proanthocyanidin consumption are also discussed. Intestinal lipid absorption, chylomicron secretion by the intestine and VLDL secretion by the liver are the processes that are most repressed by proanthocyanidins, which, therefore, induce hypolipidemic effects.     

Prodelphinidins and related flavanols in wine

Summary Liquid chromatography coupled to diode array spectrophotometry and mass spectroscopy detection (LC-DAD-MS) has been applied to the study of the proanthocyanidin composition of red wine. Analytical conditions were optimized using several flavanols previously isolated from grape seeds and pomegranate peel. Higher sensitivity was obtained in positive than in negative ion mode and electrospray ionization (ESI) proved to be more useful than chemical ionization (APCI) for the identification of flavanols with a higher degree of polymerization, since it always provided the molecular ion. Useful information for the identification of compounds was also obtained from their fragmentation patterns (MS-MS spectra). The application of the method of LC-DAD-MS set up permitted the identification of fourteen flavanols in wine: four monomers (C, catechin; EC, epicatechin; GC, gallocatechin; EGC, epigallocatechin), eight dimers (B1, B2, B3, B4, B7, GC-4,8-GC, GC-4,8-C and C-4,8-GC) and two trimers (EC-4,8-EC-4,8-C and C1). Two other heterogeneous dimers were detected, which were supposed to possess an epi(gallo)catechin unit. No important peaks corresponding to galloyl derivatives were found. As far as we know, prodelphinidins and flavanols containing GC units were identified in wine for the first time.     

A new technology for extraction and purification of proanthocyanidins derived from sea buckthorn bark

A new technology involving resin purification of proanthocyanidins extracted from sea buckthorn bark has been studied. By investigating single‐factor effects, the main factors affecting proanthocyanidin extraction were identified as extraction temperature, pH and ethanol concentration. A central composite design and response surface analysis were used to determine the optimal parameters of the extraction process (temperature 21 °C, pH 5.13, ethanol concentration 65%). The optimal resin for purification, D3520, was selected from 16 different resins by means of static adsorption and dynamic adsorption/desorption tests. After using this resin to purify the crude extract, a proanthocyanidin extract was obtained whose yield and purity were above 80% and greater than 95% respectively. Procyanidin dimers and trimers predominated among oligomer procyanidins of the proanthocyanidin extract according to analyses by high‐performance liquid chromatography (HPLC) and HPLC/mass spectrometry. Copyright © 2005 Society of Chemical Industry     

光皮木瓜原花青素提取物对不同饱和度油脂氧化稳定性的影响

以光皮木瓜为原料,采用水、50%乙醇、60%丙酮提取光皮木瓜原花青素。利用超高效液相色谱-质谱联用仪对3种原花青素提取物进行成分分析,同时采用Schaal加速氧化的方法考察其对3种不同饱和度油脂（花生油、葵花籽油、亚麻籽油）氧化稳定性的影响。结果表明：3种原花青素提取物中的原花青素主要由原花青素高聚体和低聚体组成,其中高聚体含量均在90%以上,低聚体以原花青素二聚体为主。在加速氧化过程中,3种原花青素提取物均能有效延缓油脂的氧化。在花生油中,与空白样品相比,水提取物能够使油脂过氧化值下降33.00%,显著高于乙醇提取物（1866%）和丙酮提取物（9.15%）。在葵花籽油和亚麻籽油中,乙醇提取物和丙酮提取物对油脂氧化的抑制能力相似且强于水提取物。光皮木瓜原花青素可以作为一种天然抗氧化剂,用于提高油脂的氧化稳定性。     

Rethinking the Mechanism of the Health Benefits of Proanthocyanidins: Absorption,Metabolism, and Interaction with Gut Microbiota

Proanthocyanidins, as the oligomers or polymers of flavan‐3‐ol, are widely discovered in plants such as fruits, vegetables, cereals, nuts, and leaves, presenting a major part of dietary polyphenols. Although proanthocyanidins exert several types of bioactivities, such as antioxidant, antimicrobial, cardioprotective, and neuroprotective activity, their exact mechanisms remain unclear. Due to the complexity of the structure of proanthocyanidins, such as their various monomers, different linkages and isomers, investigation of their bioavailability and metabolism is limited, which further hinders the explanation of their bioactivities. Since the large molecular weight and degree of polymerization limit the bioavailability of proanthocyanidins, the major effective site of proanthocyanidins is proposed to be in the gut. Many studies have revealed the effects of proanthocyanidins from different sources on changing the composition of gut microbiota based on in vitro and in vivo models and the bioactivities of their metabolites. However, the metabolic routes of proanthocyanidins by gut microbiota and their mutual interactions are still sparse. Thus, this review summarizes the chemistry, absorption, and metabolic pathways of proanthocyanidins ranging from monomers to polymers, as well as the mutual interactions between proanthocyanidins and gut microbiota, in order to better understand how proanthocyanidins exert their health‐promoting functions.     

Comparative study of phenolic content and antioxidant activity of strawberry puree,clear, and cloudy juices

The aim of this study was to determine the concentrations of phenolic compounds and their antioxidant activity in different kinds of juice: clear, cloudy, and puree which were made from three different strawberry cultivars (Elkat, Kent, and Senga Sengana). The anthocyanins, p-coumaric acid, ellagic acid, quercetin, keampferol derivatives, (+)-catechin, proanthocyanidins content and degree of proanthocyanidin polymerization, were determined both in the fresh and after 6 months of storage at 4 and 30 °C. Freshly produced juices contained higher amounts of phenolics, especially of anthocyanins and proanthocyanidins, than those stored for 6 months at 4 and 30 °C. The processing of the clear juice showed the higher loss of all phenolic compounds. The antioxidant capacity was the smallest for clear, and the highest for the puree juices. This was assessed by measurements made with different antioxidant activity assays: ABTS and FRAP. The puree of strawberry juice had significantly higher levels of the phenolic compounds and showed more antioxidant activity than the clear and cloudy juices, before and after storage in all strawberry cultivars.     

Temperature influences epimerization and composition of flavanol monomers,dimers and trimers during cocoa bean roasting

Cocoa consumption is suggested to promote many health benefits, since cocoa is a rich source of flavanols; but amounts and profiles of flavanols depend strongly on the bean type, origin and manufacturing process. Roasting is known as a crucial step in technical treatment of cocoa, which leads to flavanol losses and modifications, especially the epimerization of (−)-epicatechin to (−)-catechin. This study monitors the influence of cocoa bean roasting on the composition of flavanol monomers to trimers, with special focus on epimerization, which was quantified for procyanidin dimers, and also observed for trimers for the first time. Five dimeric and two trimeric potential epimerization products were detected and the extent of epimerization during cocoa roasting was shown to be a function of temperature. The data also showed remarkable variations in the change of flavanol content. The quantified flavanols decreased about 50% in Java beans and increased about 30% in Ivory Coast beans, despite being roasted under equal conditions.