Distribution of phenolic compounds within seed and seedlings of two Vicia faba cvs differing in their seed tannin content,and study of their seed and root phenolic exudations

The present study analysed the physiology of phenolic exudation by the seed and the root of two Vicia faba cultivars, one rich in condensed tannin (cv. Alfred) and one free-tannin cultivar (cv. Blandine). We first analysed the phenolic exudation from the intact seeds and from the different seed tissues (coat and cotyledon separately). Results indicated that the whole seed exudation in water after 24 h was reduced when the seed was incubated at 4°C in comparison with 30°C. The characterisation and separation of phenolic compounds was achieved by HPLC procedures. The two cultivars of Vicia faba, cv. Blandine and cv. Alfred, were containing in the seed two different chemical patterns. The phenolic patterns of the cv. Alfred seed coat was dominated by catechin derivatives, condensed tannins and flavones. The phenolic pattern of cotyledon and whole seed are very closed and namely made of phenolic acids, and catechin, and flavones as minor compounds. For cv. Blandine, the seed coats contain phenolic acids, flavones, flavonols and dihydroflavonols; the phenolic profile of whole seeds and cotyledons were mainly based on phenolic acids. The kinetic of root phenolic exudation was analysed on the first 21 days of the root growth; the data indicated that phenolic compounds were rapidly released from the emerging root as the amounts of phenolic compounds in exudates were maximum the first day after the seed germination.The HPLC analysis of the phenolic compounds exudated by the root, depicted catechin, phenol acids derivatives and various flavones and flavanones.     

Inhibitors in Sorghum biomass during growth and processing into fuel

The presence and inhibitory activity of phenolic compounds in sorghum biomass were determined. Sorghum contains phenolic compounds at all stages of growth, with higher levels in leaves and glumes compared to stalks and caryopses. The phenolic compounds inhibited alpha- and gluco-amylase activity. Storage of sorghum resulted in increased levels of some phenolic acids. Levels of free phenolic compounds in ensiled sorghum leachate were sufficient to inhibit the hydrolysis of carbohydrates. The phenolic compounds from sorghum appeared to be detoxified during anaerobic digestion.     

薄壳山核桃酚类代谢物研究进展

薄壳山核桃(Carya illinoensis)富含酚类代谢物,具有显著的抗氧化活性。近年来,我国薄壳山核桃产业快速发展,种植面积迅速扩大。明确薄壳山核桃中的酚类代谢物组成及保健功效对于促进健康产业发展具有重要意义。迄今为止,从薄壳山核桃中已检测出酚类代谢物67个,其中包括单宁36个、类黄酮22个、酚酸9个,水解后检测出酚类代谢物苷元34个。该文主要对薄壳山核桃酚类代谢物的组成、提取方法、含量、药理活性及与采后贮藏特性的关系进行综述,以期为今后深入研究薄壳山核桃酚类代谢物与其生理活性的关系及挖掘薄壳山核桃酚类代谢物的保健价值提供依据。     

忍冬属植物花药药隔的特化结构及其生物学意义

花药药隔的特化结构通常具有重要的生物学意义。目前,有关药隔特化出贮存酚类物质的异细胞群的研究报道甚少,该特化结构有何生物学意义则未见报道。本研究运用半薄切片技术、冰冻切片技术、组织化学和细胞化学等方法对忍冬属Lonicera植物特化药隔异细胞群的主要内含物进行定性分析,实验证明忍冬属特化药隔异细胞群内含丰富的酚类物质。另外通过对忍冬属华南忍冬L.confusa药隔薄壁组织的发育及其与药隔维管束的关系分析,推测忍冬属特化药隔可能一方面对发育中的花药维管束起保护作用,另一方面又可作为酚类物质的临时贮存场所。同时研究发现忍冬属植物特化药隔异细胞群的形成及其分布特点可能具有重要的系统学意义。     

Bioavailability of phenolic acids

Two large classes of phenolic acids were comprised in this review: benzoic acid derivatives and cinnamic acid derivatives. They have been found to be very extended in fruits and vegetables at different concentrations. For example, hydroxycinnamic acids concentration was higher than that found for hydroxybenzoic acids. Concerning their consumption, hydroxycinnamic acids provide larger contributions to the total polyphenol intake than benzoic acid derivatives or flavonoids. This phenolic acid intake is led by the coffee intake since it has very rich concentrations in hydroxycinnamic acids. Moreover, several experimental and epidemiological studies report the protection of phenolic acids against various degenerative diseases. However, despite all these interesting attributions and even if phenolic acids are the main polyphenols consumed, their bioavailability has not received as attention as that flavonoids. This concept is an essential step to understand the health-promoting properties of phenolic acids and to serve as tool to design in vivo and in vitro experiments to know their biological properties. Therefore, a compilation of bioavailability data of phenolic acids have been presented here paying attention to the two types of phenolic acid bioavailability, direct and indirect derived from the direct phenolic acid and flavonoid consumption, respectively. Then, a new relevant concept which may be named as total bioavailability of phenolic acids includes the direct absorption and metabolism of phenolic acids from food consumption and phenolic acids bioavailability as a result of the cleavage on the main skeleton ring of flavonoids by the gut microflora.     

Postprandial LDL phenolic content and LDL oxidation are modulated by olive oil phenolic compounds in humans

Olive oil phenolic compounds are potent antioxidants in vitro, but evidence for antioxidant action in vivo is controversial. We examined the role of the phenolic compounds from olive oil on postprandial oxidative stress and LDL antioxidant content. Oral fat loads of 40 mL of similar olive oils, but with high (366 mg/kg), moderate (164 mg/kg), and low (2.7 mg/kg) phenolic content, were administered to 12 healthy male volunteers in a cross-over study design after a washout period in which a strict antioxidant diet was followed. Tyrosol and hydroxytyrosol, phenolic compounds of olive oil, were dose-dependently absorbed (p<0.001). Total phenolic compounds in LDL increased at postprandial state in a direct relationship with the phenolic compounds content of the olive oil ingested (p<0.05). Plasma concentrations of tyrosol, hydroxytyrosol, and 3-O-methyl-hydroxytyrosol directly correlated with changes in the total phenolic compounds content of the LDL after the high phenolic compounds content olive oil ingestion. A 40 mL dose of olive oil promoted a postprandial oxidative stress, the degree of LDL oxidation being lower as the phenolic content of the olive oil administered increases. In conclusion, olive oil phenolic content seems to modulate the LDL phenolic content and the postprandial oxidative stress promoted by 40 mL olive oil ingestion in humans.     

Investigation of chitosan-phenolics systems as wood adhesives

Chitosan-phenolics systems were investigated as wood adhesives. Adhesion between two pieces of wood veneer developed only when all three components-chitosan, a phenolic compound, and laccase-were present. For the adhesive systems containing a phenolic compound with only one phenolic hydroxyl group, adhesive strengths were highly dependent upon the chemical structures of phenolic compounds used in the system and the relative oxidation rates of the phenolic compounds by laccase. The adhesive strengths were also directly related to the viscosity of the adhesive systems. However, for the adhesive systems containing a phenolic compound with two or three phenolic hydroxyl groups adjacent to each other, no correlations among adhesive strengths, relative oxidation rates of the phenolic compounds by laccase, and viscosities were observed. The adhesion mechanisms of these chitosan-phenolics systems were proposed to be similar to those of mussel adhesive proteins.     

Allelopathic Interactions Involving Phenolic Acids

A major concern regarding allelopathic interactions involving phenolic acids in no-till systems pertains to the fact that concentrations of individual phenolic acids recoverable from field soils are well below levels required for inhibition of germination and seedling growth in laboratory bioassays. Field soils contain a variety of phenolic acids as well as other toxic and nontoxic organic compounds that are available to interact with seeds and roots; whereas in laboratory bioassays, with few exceptions, single phenolic acids have been tested. Studies of mixtures of phenolic acids and other toxic (e.g., methionine) and nontoxic (e.g., glucose) organic compounds in laboratory bioassays indicate that the action of a single phenolic acid is not representative of the actions of such mixtures. Specifically, as the number of phenolic acids added to soil increased, concentrations of the individual phenolic acids required to bring about a growth inhibition declined. The addition of other organic compounds (e.g., glucose, methionine) to the soil also reduced the concentration of a phenolic acid (e.g., p-coumaric acid) required for growth inhibition. These results support the hypothesis that in the field mixtures of phenolic acids and other organic compounds can cause inhibitory effects even though the concentrations of individual compounds are well below their inhibitory levels.     

酚酸类物质的化感作用研究进展

酚酸类物质是普遍存在于高等植物组织并与植物生长密切相关的次级代谢产物。几十年来,人们对酚酸类化合物的认识逐渐加深,但关于其在生物学、生态学以及农业上的作用机制仍不是很清楚。因此,进一步了解这些生物分子将有助于生态系统的维持与保护。重点介绍了酚酸类物质的来源及化感作用,微生物对酚酸类物质的降解机理,代谢途径及相应分子水平的研究,指出了酚酸类物质研究中存在的问题,同时展望了酚酸类物质的研究方向与前景。     

Histochemical Localization of Phenolic Deposits in Leaf Blades of Eragrostis racemosa

The distribution of phenolic deposits in the leaves of Eragrostisracemosa from different habitats was investigated during cultivationunder uniform environmental conditions. The plants retainedtheir leaf phenolic distribution pattern over a period of 8months. Plants from dry habitats had phenolic inclusions inboth epidermal layers, whereas phenolic deposits were absentor only occurred in the abaxial epidermal layers of plants occupyingmoist habitats. Eragrostis racemosa, narrow-heart love grass, Poaceae, phenolic deposits, epidermis, histochemistry, anatomy     

环渤海湾地区连作苹果园土壤中酚酸类物质变化

分析了山东昌邑、栖霞、蓬莱,辽宁大连、抚宁、绥远,河北昌黎、青县等地苹果园连作土壤中酚酸物质的组成和含量,结果表明:连作障碍发生的苹果园土壤中酚酸类物质的组成和含量在不同地区、不同土层厚度间存在显著差异。苹果园土壤中酚酸类物质的含量从春季到秋季随时间的延长逐渐减少,但过程缓慢。且非连作园土壤中酚酸类物质含量显著少于连作土。连作土壤中酚酸物质的组成和含量在不同季节间差异显著,尤其春季土壤中酚酸物质的种类与夏季和秋季显著不同。这可能是因为植物在不同季节分泌的酚酸类物质种类和含量有差别.不同土层中酚酸物质的分布因季节不同而有显著差异。夏季土壤中酚酸物质主要分布在浅层土壤中,而秋季则主要分布在深层土壤中。这可能是由于浇水等果园管理措施和自然降水对土壤中的酚酸物质产生的淋溶作用,使得大量的酚酸物质向深层土壤运动,最终造成了秋季果园连作土中随土层加深而酚酸物质含量增加的现象。不同地区苹果园连作土中,对羟基苯甲酸、(+)-儿茶素、咖啡酸、阿魏酸含量与非连作土无显著差异,而焦性没食子酸、绿原酸和根皮苷显著高于非连作土。焦性没食子酸、绿原酸和根皮苷可能是引起山东、辽宁、河北地区苹果园连作障碍的关键酚酸物质。     

Redfield revisited: variability of C:N:P in marine microalgae and its biochemical basis

Cytological events immediately following plasmogamy in Durvillaea potatorum are described. Eggs contain several types of cytoplasmic vesicle differing in size and appearance. Histochemical tests and measurements are used to characterise and distinguish different types of vesicle containing phenolic compounds, lipids and polysaccharides. Within 2 min of plasmogamy, small phenolic vesicles located just below the egg membrane undergo mass synchronised exocytosis. The contents of these vesicles are discharged as phenolic bodies on the outside of the membrane. Secretion of phenolic bodies precedes secretion of the primary zygote wall by several minutes. Limited secretion of phenolics also occurs in unfertilised eggs. Peripheral phenolic vesicles are distinguishable from physodes, which also contain phenolic compounds but which are significantly larger and tend to be localised around the egg nucleus. The possible functional significance of the phenolic bodies is discussed. Coated pits and vesicles are common in zygotes, and their presence is evidence for endocytosis.     

LC-MALDI-TOF MS-Based Rapid Identification of Phenolic Acids

This study is the first on combined HPLC and MALDI-TOF MS analysis of phenolic acids. The analyses were carried out for phenolic acid mixtures and showed a unique, individual co-crystalline pattern for each phenolic acid. HPLC could distinguish phenolic acids and MALDI-TOF MS provided comparable mass (m/z) profiles for the samples. This combined study proved to be rapid in the accurate identification and structural analysis of phenolic acids with different masses.     

Dark-induced changes in the content of phenolic acids in callus culture of alfalfa (Medicago sativa)

The changes in the content of free and esterified phenolic acids extracted with methanol and the phenolic acids nonextractable with this solvent were studied during a long term cultivation (4 subcultures, 27 weeks total) of alfalfa callus in darkness and light. The total content of phenolic acids in the callus grown in darkness was lower as compared to their content in callus cultivated under 10/14 h light/darkness regime. It was decreasing during cultivation differently in the two treatments being in light-grown callus dependent on the length of cultivation and decreasing by each subcultivation in darkness. The portion of benzoic acid derivatives related to the total phenolic acids changed with the age of the culture reaching 90 % after the fourth subcultivation in darkness while only 45 % in light. Considerable decrease of the content of esterified form of phenolic acids accompanied by relatively stable content of free and firmly bound phenolic acids caused significant decrease of esters as related to total phenolic acids (from 87 % to 25 %).     

源于解淀粉芽胞杆菌酚酸脱羧酶的克隆与表达

【背景】酚酸脱羧酶催化分解酚酸产生的4-乙烯基酚类物质可用于食品添加剂及香精香料行业,而酚酸脱羧酶的表达水平相对较低,因此,高水平的酚酸脱羧酶是工业规模生产4-乙烯基酚类物质的先决条件。【目的】克隆解淀粉芽胞杆菌的酚酸脱羧酶基因,实现在大肠杆菌中的高效异源表达,分析酚酸脱羧酶的底物特异性,并对其表达条件进行优化。【方法】通过PCR技术获得酚酸脱羧酶的基因,构建重组基因工程菌,将测序结果与其他酚酸脱羧酶序列进行比对,利用IPTG诱导方法高效表达蛋白。将重组酚酸脱羧酶与4种不同的底物进行反应,设计响应面试验对诱导条件进行优化。【结果】酚酸脱羧酶对对香豆酸、阿魏酸、咖啡酸、芥子酸的比酶活比率为:100:23.33:15.39:10.51。结合与其他酚酸脱羧酶比对结果发现酚酸脱羧酶家族的C末端区域氨基酸序列的变异率最高,这与酚酸脱羧酶的底物特异性和催化机制有关。通过单因素和响应面试验得到酚酸脱羧酶诱导表达的最佳条件为:2×YT培养基,诱导温度30°C,接种量1.78%,诱导时机3.8 h,IPTG1.25mmol/L,诱导时间18h,此时预测酶活和实际酶活分别为47.61IU/mL和47.55IU/mL。【结论】应用响应面法优化酚酸脱羧酶的诱导表达是可行的,本试验为以后生产稳定、高产的酚酸脱羧酶以及了解其催化机理提供了重要的理论基础。     

Biochemical applications of chemically induced nuclear polarization in phenols, peptides, catecholamines and related molecules.

A photochemical method for producing proton nuclear polarization in phenolic biogenic molecules such as tyrosyl polypeptides and phenolic amines is described. The nuclear polarization is due to the reversible hydrogen-atom transfer from the phenolic hydroxy group to triplet photoexcited xanthene-dye molecules. Typical results obtained with insulin, catecholamines and other phenolic molecules are treated in detail.     

Differential resistance to freezing and spatial distribution in a chemically polymorphic plant Thymus vulgaris

Secondary compounds play multiple ecological roles. In this study, we present novel experimental evidence of differential tolerance to freezing temperatures among chemotypes of a chemically polymorphic plant, Thymus vulgaris. Non‐phenolic chemotypes showed a significantly better survival and re‐growth after early‐winter freezing (?10° in early December) than phenolic chemotypes. Comparison of temperature data (1971–2002) at a phenolic and non‐phenolic site showed that whereas early‐winter freezing occurred in 6 years in the non‐phenolic site they never occurred at the phenolic site. Observations of trichome morphology (where the essential oil is stocked) with and without intense freezing indicate that non‐phenolic chemotypes may escape any negative effects of freezing by releasing their essential oil into the atmosphere during severe freezing. The correlation between tolerance of freezing and local temperature regimes strongly suggests that differential freezing resistance is a key ingredient of the distribution of thyme chemotypes in space.     

Lipase-catalyzed synthesis of phenolic lipids from fish liver oil and dihydrocaffeic acid

The enzymatic synthesis of phenolic lipids by lipase-catalyzed transesterification of dihydrocaffeic acid (DHCA) with fish liver oil was investigated in a selected organic solvent medium. These synthesized phenolic lipids have potential use as nutraceutical products. Using a molar ratio of 1:8 DHCA to fish liver oil in hexane:2-butanone mixtures of 75:25 and 85:15 (v/v), the lipase-catalyzed reaction resulted in maximum conversion of 55.8 and 65.4%, respectively. The maximum conversion of phenolic monoacylglycerols in hexane:2-butanone mixture of 75:25 and 85:15 (v/v) was 40.3 and 37.7%, respectively; using the same solvent mixtures, the conversions of the phenolic diacylglycerol were 15.8 and 36.8%, respectively. Hexane:2-butanone mixture of 75:25 (v/v) was, therefore, the best organic solvent mixture for the production of phenolic monoacylglycerols, while that of 85:15 (v/v) was best for the production of phenolic diacylglycerols. The phenolic lipids produced from the fish liver oil and DHCA demonstrated antioxidant property as indicated by its free radical scavenging capacity.     

Phenolic substances in the cell suspension culture ofCentaurium erythraea

The content of phenolic substances in the cell suspension culture ofCentaurium erythraea fluctuated during a 21-day-long subcultivation period in dependence on the growth phase. The total relative content of the phenolics reached its maximum at the time of transition to the exponential growth phase, similarly as the fraction of free phenolic acids, glycosides, and the fraction of phenolic acids released from the cells after alcaline hydrolysis. On the other hand, the content of phenolic acid esters decreased at this growth phase of the culture. Changes in the level of phenolic substances in the culture medium corresponded in their character to changes in the relative content of the phenolics in the cells.