紫甘薯花青素的功能特性研究

采用抗坏血酸和BHT作为对照,测定了紫甘薯花青素的还原能力、对食用油脂的抗氧化能力及对.OH自由基和O2-.自由基的清除能力。结果表明,当浓度大到0.5mg/mL时,其还原能力接近抗坏血酸;在豆油基质中紫甘薯花青素的抗氧化活性高于BHT;在试验质量浓度范围内,紫甘薯花青素对.OH自由基的清除率为81.2%,活性略低于抗坏血酸;对O2-.自由基的清除率可达91.3%,活性强于BHT。     

Measurement of Antioxidant Activity of Wine Catechins,Procyanidins, Anthocyanins and Pyranoanthocyanins

Nowadays, there is considerable interest in finding out about antioxidants that are consumed in the habitual diet. It is known that polyphenols are involved in reducing the risk of diseases associated with oxidative stress. The in vitro antioxidant activity of the principal wine polyphenolic compounds (catechins, procyanidins, anthocyanins and pyranoanthocyanins) was studied in this work. Four distinct methods were used to assess the antioxidant capacity of the tested compounds: inhibition of peroxynitrite mediated tyrosine nitration, TEAC (Trolox equivalent antioxidant capacity assay), FRAP (Ferric reducing/antioxidant power assay) and TBARS (thiobarbituric acid reactive substances) methods. In general, it could be concluded that procyanidins were, among the in vitro tested groups, the ones which showed more antioxidant capacity using the four different methods, followed by anthocyanins and pyranoanthocyanins. On the basis of the simple regression testing, there was a statistically significant relationship between these different methods used in aqueous phase (r > 0.92). However, no correlation was found between the results obtained in lipid media with the TBARS method and those obtained in the aqueous media (peroxynitrite scavenging activity, TEAC and FRAP methods).     

花色苷提取及纯化研究进展

花色苷属于黄酮类化合物,广泛存在于各种植物的器官中,它不仅是自然界重要的水溶性色素,还同时具有良好的抗氧化、抗癌、预防疾病等多种生物活性,因而被广泛应用于食品、制药、化妆品等行业。天然植物花色苷的提取和纯化是花色苷应用的前提。该文综述了花色苷提取与纯化的最新研究进展,分析比较了不同提取和纯化方法对产品提取率及纯度的影响,为进一步开展植物花色苷研究,实现花色苷的高效提取与高值化利用提供参考。     

Isolation,Stability, and Antioxidant Activity of Anthocyanins from Lycium ruthenicum Murray and Nitraria Tangutorum Bobr of Qinghai-Tibetan Plateau

Four anthocyanins, namely petunidin-3,5-O-diglucosides(L1), petuinidi-3-O-rutinoside(trans-p-coumaroyl)-5-O-glucosides(L2),cyanidin-3-O-(trans-p-coumaroyl)-diglucoside(N1), and pelargonidin -3-O-(trans-coumaroyl)-diglucoside (N2) have been obtained by preparative HPLC from Lycium ruthenicum Murray and Nitraria Tangutorum Bobr. The stability and antioxidant capacity of these four individual anthocyanins were carried out in this paper. For stability capacity examination, pH stability (pH 1, 3, 5, 7, 9, 11 and 13), photostability (exposed to light), and thermostability (5°C and 35°C) were systematically investigated. As for antioxidant capacity evaluation, DPPH radicals scavenging assay and ferric reducing antioxidant power (FRAP) assay were employed. The results showed that acidic solution tended to be favorable condition for all anthocyanins mentioned above. However, as the pH of solution increased, anthocyanins were becoming more unstable. In photostability and thermostability assays, the acylated anthocyanins behaved more stable than non-acylated anthocyanins. These results also indicated that the anthocyanins which had more powerful radical scavenging ability (DPPH) tended to possess stronger FRAP capacity. These data also indicated that the structures of aglycone and acyl group greatly affected the stability and antioxidant capacity of anthocyanins. Given the results obtained from our study, the high stability and antioxidant merits that the purified anthocyanins displayed made the two berries of Qinghai-Tibetan plateau become ideal resources of natural pigment.     

Effects of Berry Anthocyanins on Cognitive Performance,Vascular Function and Cardiometabolic Risk Markers: A Systematic Review of Randomized Placebo-Controlled Intervention Studies in Humans

Supplementation with anthocyanins, which are a type of flavonoids mainly found in various berries, is hypothesized to be a promising approach to lower the risk of developing cognitive decline. The aim of this systematic review was to provide a comprehensive overview of dietary intervention trials describing effects of berry anthocyanins on cognitive performance in humans, while also addressing potential underlying mechanisms. A total of 1197 articles were identified through a systematic search, and 49 studies reporting effects on cognitive performance (n = 18), vascular function (n = 22), or cardiometabolic risk markers (n = 32) were included. Significant improvements were observed on memory, while some of the studies also reported effects on attention and psychomotor speed or executive function. Vascular function markers such as brachial artery flow-mediated vasodilation were also affected and consistent evidence was provided for the beneficial effects of berry anthocyanins on endothelial function. Finally, studies reported improvements in blood pressure, but effects on metabolic risk markers (e.g. carbohydrate and lipid metabolism) were less consistent. In conclusion, this review provides evidence for the beneficial effects of berry anthocyanins on cognitive performance as memory improved. Whether observed anthocyanin-induced improvements in vascular function and blood pressure underlie beneficial effects on cognitive performance warrants further study.     

黑加仑花色苷的分离纯化及其热降解动力学

以黑加仑为原料,采用AB-8大孔树脂-Sephadex LH-20凝胶柱层析联用方法和液相色谱-质谱联用技术对黑加仑花色苷进行分离纯化和组分鉴定;分析了不同纯度花色苷在不同pH和温度下的降解动力学;通过1,1-二苯基-2-三硝基苯肼(DPPH)和2,2'-联氮基-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)自由基的清除评价了不同纯度花色苷的抗氧化能力。结果表明:黑加仑中包含飞燕草素-3-葡萄糖苷、矢车菊素-3-芸香糖苷、牵牛花素-3-葡萄糖苷、芍药素-3,5-二己糖苷和锦葵素-3-半乳糖苷5种组分。经分离纯化后最终获得2种花色苷,分别为飞燕草素-3-葡萄糖苷(A_3)和矢车菊素-3-芸香糖苷(A_4)。pH 3.0和温度50℃时,花色苷的热稳定性最强。不同纯度花色苷组分热降解均符合一级动力学模型。经大孔树脂纯化后的花色苷(A_1)、乙酸乙酯萃取后的花色苷(A_2)、A_3和A_4对DPPH自由基清除率的半数抑制浓度(IC50)分别为9.45、8.17、5.95和7.62 mg/L,而对ABTS自由基清除率的IC50分别为99.38、97.21、78.19和85.54 mg/L。     

新型受阻酚类抗氧剂的合成与性能研究

以2,6-二叔丁基苯酚原料,合成了1种新型受阻酚抗氧剂2,6-二叔丁基-4-氨基苯酚,研究了该新型抗氧剂对聚烯烃材料的抗氧化作用。结果表明,以锌粉为还原剂,8.5 %氯化钙水溶液用量为90 mL,溶剂乙醇用量为100 mL, 在80 ℃下反应8 h,新型受阻酚抗氧剂的产率达80 %以上,熔程为112.2~113.3 ℃。该抗氧剂在2种聚烯烃材料中均具有良好的加工稳定性和抗氧化性能,氧化诱导期与市售抗氧剂1076相当,优于抗氧剂BHT;经5次挤出后,添加新型抗氧剂的聚烯烃材料的熔体流动速率变化很小,但拉伸强度和断裂伸长率大幅度提高。     

Synthesis and Properties of Quinone Copolymers Possessing Antioxidant and Antihypoxemic Properties

Copolymers including hydroquinone and vinylpyridine units have been prepared by the copolymerization reaction of quinones with vinylpyridines. By-products of these reactions are the homopolymer and the hydroquinone form of the respective quinone. It has been established that in the formation of the copolymers, the weak intermolecular complexes of quinones (Qs) with vinylpyridines (VPs) have an essential contribution. The kinetics of Q copolymerization with VP in the presence of triethylamine has been investigated. The values of the reaction order based on the components, the rate constants and activation energies of the copolymerization processes have been determined. The copolymers prepared are soluble in polar organic solvents, have high reactivity for electron exchange, and possess antioxidant, antihypoxemic and antistatic properties. © 1997 SCI     

Antioxidant activity of grape extracts in a lecithin liposome system

Extracts of 14 different grapes were tested for their antioxidant activities in a copper-catalyzed lecithin liposome oxidation assay and analyzed for their phenolic components by high-performance liquid chromatography (HPLC). The total phenolic contents of the grape extracts varied from 176 to 1236 mg gallic acid equivalents (GAE)/L. Extracts of red wine grape varieties contained higher concentrations of phenolics than other varieties. When compared at the same 20 μM GAE basis, the grape extracts inhibited formation of conjugated diene hydroperoxides by 25.1 to 67.9%, and hexanal formation by 49.3 to 97.8%. Extracts of red table grape varieties Red Globe and Emperor and white wine grape varieties Chardonnay and Sauvignon Blanc gave the highest antioxidant activities. The relative percentage inhibition of conjugated dienes and hexanal correlated with total phenols (r=0.86 and 0.89). HPLC analyses showed that anthocyanins were the most abundant phenolic compounds in extracts of red grapes, and flavonols were most abundant in extracts of white grapes.     

高温抗氧剂对聚苯硫醚结构与性能的影响

利用微型双螺杆挤出机将耐高温半受阻酚抗氧剂GA?80通过熔融共混与聚苯硫醚(PPS)复合,采用场发射扫描电子显微镜、热失重分析仪、差示扫描量热仪和X射线光电子能谱仪研究GA?80对PPS基复合材料的形态结构、结晶行为、热氧稳定性、氧化诱导温度和表面元素变化的影响.结果表明,GA?80与PPS基体存在较好的相容性,可在基...     

Advanced Knowledge of Three Important Classes of Grape Phenolics: Anthocyanins,Stilbenes and Flavonols

Grape is qualitatively and quantitatively very rich in polyphenols. In particular, anthocyanins, flavonols and stilbene derivatives play very important roles in plant metabolism, thanks to their peculiar characteristics. Anthocyanins are responsible for the color of red grapes and wines and confer organoleptic characteristics on the wine. They are used for chemotaxonomic studies and to evaluate the polyphenolic ripening stage of grape. They are natural colorants, have antioxidant, antimicrobial and anticarcinogenic activity, exert protective effects on the human cardiovascular system, and are used in the food and pharmaceutical industries. Stilbenes are vine phytoalexins present in grape berries and associated with the beneficial effects of drinking wine. The principal stilbene, resveratrol, is characterized by anticancer, antioxidant, anti-inflammatory and cardioprotective activity. Resveratrol dimers and oligomers also occur in grape, and are synthetized by the vine as active defenses against exogenous attack, or produced by extracellular enzymes released from pathogens in an attempt to eliminate undesirable toxic compounds. Flavonols are a ubiquitous class of flavonoids with photo-protection and copigmentation (together with anthocyanins) functions. The lack of expression of the enzyme flavonoid 3′,5′-hydroxylase in white grapes restricts the presence of these compounds to quercetin, kaempferol and isorhamnetin derivatives, whereas red grapes usually also contain myricetin, laricitrin and syringetin derivatives. In the last ten years, the technological development of analytical instrumentation, particularly mass spectrometry, has led to great improvements and further knowledge of the chemistry of these compounds. In this review, the biosynthesis and biological role of these grape polyphenols are briefly introduced, together with the latest knowledge of their chemistry.     

二苯并噻吩结构和性质的理论研究

为了探究煤中噻吩类有机硫化合物降解规律,采用密度泛函理论来对煤的一种含硫模型化合物进行量子化学方面的计算与研究。采用Materials Studio中的Dmol~3程序分析了与煤有关的含硫模型化合物二苯并噻吩(DBT)的结构和相关性质(键角键长、电荷、振动频率、热力学性质、分子反应活性及稳定性)。计算结果显示处于噻吩环结构中的C—S键键能和C—C键键能相等,噻吩环中的C—S键键能大于非环中的C—S键键能;预测噻吩中C—S键更难断裂;模型化合物中的S原子处HOMO伸展较大,是给电子的位置,S原子易失去电子发生反应。     

Theoretical Evaluation of Sulfur-Based Reactions as a Model for Biological Antioxidant Defense

Sulfur-containing amino acids, Methionine (Met) and Cysteine (Cys), are very susceptible to Reactive Oxygen Species (ROS). Therefore, sulfur-based reactions regulate many biological processes, playing a key role in maintaining cellular redox homeostasis and modulating intracellular signaling cascades. In oxidative conditions, Met acts as a ROS scavenger, through Met sulfoxide formation, while thiol/disulfide interchange reactions take place between Cys residues as a response to many environmental stimuli. In this work, we apply a QM/MM theoretical–computational approach, which combines quantum–mechanical calculations with classical molecular dynamics simulations to estimate the free energy profile for the above-mentioned reactions in solution. The results obtained, in good agreement with experimental data, show the validity of our approach in modeling sulfur-based reactions, enabling us to study these mechanisms in more complex biological systems.     

Insights into the Mechanisms of Action of Proanthocyanidins and Anthocyanins in the Treatment of Nicotine-Induced Non-Small Cell Lung Cancer

In traditional medicine, different parts of plants, including fruits, have been used for their anti-inflammatory and anti-oxidative properties. Plant-based foods, such as fruits, seeds and vegetables, are used for therapeutic purposes due to the presence of flavonoid compounds. Proanthocyanidins (PCs) and anthocyanins (ACNs) are the major distributed flavonoid pigments in plants, which have therapeutic potential against certain chronic diseases. PCs and ACNs derived from plant-based foods and/or medicinal plants at different nontoxic concentrations have shown anti-non-small cell lung cancer (NSCLC) activity in vitro/in vivo models through inhibiting proliferation, invasion/migration, metastasis and angiogenesis and by activating apoptosis/autophagy-related mechanisms. However, the potential mechanisms by which these compounds exert efficacy against nicotine-induced NSCLC are not fully understood. Thus, this review aims to gain insights into the mechanisms of action and therapeutic potential of PCs and ACNs in nicotine-induced NSCLC.     

The Anti-Neuroinflammatory Role of Anthocyanins and Their Metabolites for the Prevention and Treatment of Brain Disorders

Anthocyanins are naturally occurring polyphenols commonly found in fruits and vegetables. Numerous studies have described that anthocyanin-rich foods may play a crucial role in the prevention and treatment of different pathological conditions, which have encouraged their consumption around the world. Anthocyanins exhibit a significant neuroprotective role, mainly due to their well-recognized antioxidant and anti-inflammatory properties. Neuroinflammation is an intricate process relevant in both homeostatic and pathological circumstances. Since the progression of several neurological disorders relies on neuroinflammatory process, targeting brain inflammation has been considered a promising strategy in those conditions. Recent data have shown the anti-neuroinflammatory abilities of many anthocyanins and of their metabolites in the onset and development of several neurological disorders. In this review, it will be discussed the importance and the applicability of these polyphenolic compounds as neuroprotective agents and it will be also scrutinized the molecular mechanisms underlying the modulation of neuroinflammation by these natural compounds in the context of several brain diseases.     

Theoretical Studies of the Electronic Properties of Ceramic Materials

The first-principles orthogonalized linear combination of atomic orbitals (OLCAO) method for electronic structure studies has been applied to a variety of complex inorganic crystals. The theory and the practice of the OLCAO method in the local density approximation are discussed in detail. Recent progress in the study of electronic and optical properties of a large list of ceramic systems are summarized. Eight selected topics on different ceramic crystals focusing on specific points of interest are presented as examples. The materials discussed are AIN, Cu₂O, β-Si₃N₄, Y₂O₃, LiB₃O₅, ferroelectric crystals, Fe-B compounds, and the YBa₂Cu₃O₇ superconductor. The results include the band structure, density of states, charge density distribution, spin density distribution, effective charges, total energy and totalenergy-derived results, optical absorption, positron annihilation spectra, and more. Extension of the band theoretical approach to the study of other areas of fundamental ceramic science is also discussed.     

树莓果渣总花色苷和总多酚微波萃取工艺

采用响应面法中Box-Behnken设计对树莓果渣中总花色苷和总多酚微波辅助萃取工艺进行优化，并结合液相色谱-质谱联用技术对树莓果渣中花色苷组分进行鉴定，通过SEM观察经微波萃取和常规溶剂萃取后样品的微观结构。结果表明，微波辅助萃取树莓果渣中总花色苷和总多酚的最佳工艺参数为：萃取温度61 ℃、液料比30:1 mL/g和萃取时间5 min，在此条件下，树莓果渣总花色苷和总多酚含量分别为4.20 mg C3G/g和16.05 mg GAE/g。经微波萃取后样品细胞结构遭到严重破坏，而经传统的溶剂萃取后样品细胞结构保存完好，且微波法所得的树莓果渣总花色苷和总多酚含量明显较高。经鉴定树莓果渣中含有6种花色苷组分，分别为飞燕草素-3-葡萄糖苷、矢车菊素-3-芸香糖苷、牵牛花素-3-葡萄糖苷、芍药素-3.5-二己糖苷、芍药素-3-(6-丙二酰)-葡萄糖苷和天竺葵素-3-(6-丙二酰)-葡萄糖苷。     

Anthocyanins Profile of Grape Berries of Vitis amurensis, Its Hybrids and Their Wines

Anthocyanins are responsible for the color of grapes and wine, an important attribute of their quality. Many authors have used anthocyanins profile to classify the grape cultivars and wine authenticity. The anthocyanin profiles of grape berries of Vitis amurensis, its hybrids and their wines were analyzed by HPLC-ESI-MS/MS. The results identified 17 anthocyanins in these grape cultivars, including 11 anthocyanin monoglucosides (five pyranoanthocyanin monoglucosides and one acylated pyranoanthocyanin monoglucoside) and six anthocyanin diglucosides. Likewise, 15 kinds of anthocyanins were detected in wines, including six diglucosides and nine monoglucosides of anthocyanidins, in which four pyranoanthocyanin monoglucosides (Petunidin-3-O-glucoside-4-acetaldehyde, Malvidin-3-O-glucoside-4-pyruvic acid, Malvidin-3-O-glucoside-acetaldehyde and Peonidin-3-O-glucoside-4-pyruvic acid) were detected. In addition, a total of 14 kinds of anthocyanins including six diglucosides and eight monoglucosides of anthocyanidins were identified in skins, in which two pyranoanthocyanin monoglucosides (Peonidin-3-O-glucoside-4-pyruvic acid, Malvidin-3-O-glucoside-4-vinylphenol) and one acylated pyranoanthocyanin monoglucoside (Malvidin-3-O-(6-O-acetyl)-glucoside-4-vinylphenol) were detected. The anthocyanins profile of grape skin of V. amurensis and its hybrids consist of the anthocyanin monoglucosides, diglucosides and pyranoanthocyanins. The wines produced resulted in a slightly different anthocyanin distribution. Pelargonidin-3,5-diglucosides was first found in the skins and wines, however, no acetyl was detected in wines. The principal component analysis results suggest that the anthocyanin profiles were helpful to classify these cultivars of V. amurensis.