油橄榄叶中羟基酪醇的含量变化规律研究

以90%甲醇-水溶液为提取剂,用超声波提取不同品种、月份和树龄油橄榄叶中羟基酪醇,采用HPLC方法分析5个品种油橄榄叶中羟基酪醇的含量变化规律,同时考察阿斯、莱星等10种油橄榄叶放置3年后其中橄榄苦苷转化为羟基酪醇的趋势.结果表明:油橄榄叶中羟基酪醇含量一年生长期内有1个高峰期和1个低谷期,5～6月份的含量最高;11～...     

引种阿斯油橄榄叶中橄榄苦苷提取分离及结构鉴定

油橄榄叶主要含有橄榄苦苷、黄酮和多酚等抗氧化物.本研究以引种的希腊油橄榄阿斯为原料,采用乙醇-水(体积比60:40)对油橄榄叶进行提取,依次用石油醚和乙酸乙酯萃取,乙酸乙酯萃取相经过硅胶柱层析,再用HPLC制备色谱,得质量分数95%以上的单体,通过IR、UV、MS、NMR鉴定该化舍物为橄榄苦苷.橄榄苦苷经过酸水解,得到两个主要产物,一个为羟基酪醇,另一个为榄香酸.     

油橄榄叶提取物生物活性研究进展

指出了油橄榄叶是地中海人用于治疗某些疾病最传统的植物茶之一。油橄榄叶提取物中富含橄榄苦苷、羟基酪醇、黄酮等酚类化合物,其中橄榄苦苷具有强抗氧化、抗高血压、降血糖、降胆固醇和保护心脏等功效。对油橄榄叶提取物生物活性的研究,目前主要集中在抗氧化、抗菌、抗动脉粥样硬化和低胆固醇、低血糖以及酚类化合物成分方面,其酚类化合物在医药和保健方面广阔的运用前景已引起人们的广泛关注。因此,提出了油橄榄叶作为一种丰富又廉价的原材料,应鼓励将其高附加值作为抗氧化剂的来源进行工业生产,应用于药品、化妆品、保健品和功能性食品等方面。     

油橄榄叶橄榄苦苷酶解制备羟基酪醇的研究

以1 g油橄榄叶提取物为原料,采用高效液相色谱法测定油橄榄叶橄榄苦苷(OE)和羟基酪醇(HT)的含量,筛选得到适合用于OE酶解制备HT的酶,通过单因素和正交试验优化酶解工艺,并考察了HT、OE和油橄榄叶提取物清除二苯基苦基肼(DPPH)自由基的抗氧化活性。结果表明,在相同酶活力条件下,半纤维素酶对OE的降解和HT的制备都有着很好的效果,其次为纤维素酶和β-葡萄糖苷酶。半纤维素酶降解OE的最佳工艺为温度60℃、p H值5.5、酶量40 mg、时间6 h,得到HT质量分数为6.07%,OE降解率为85.28%。酸解、碱解和酶解方法的比较结果表明,盐酸水解后HT质量分数可达7.41%,效果略优于酶水解;但Na OH水解后HT质量分数仅为4.09%。DPPH自由基清除实验结果表明,DPPH自由基清除能力为HT维生素COE2,6-二叔丁基-4-甲基苯酚油橄榄叶提取物,HT的半数抑制质量浓度(IC50)值可达1.07 mg/L。     

油橄榄羟基酪醇的生物合成及其衍生物研究进展

介绍了传统化学合成羟基酪醇的方法,针对化学合成反应步骤多、催化剂昂贵、产率低、污染大等问题,重点总结了以橄榄苦苷和酪醇为原料生物法合成羟基酪醇的途径,同时还综述了羟基酪醇烷基醚、脂肪酸酯、糖基化等衍生物的制备方法、生物活性及其构效关系,为羟基酪醇及其衍生物批量制备及其抗肿瘤、抗癌、心脑血管疾病新药的筛选提供参考和指导作用。     

羟基酪醇的热稳定性和分解动力学研究

研究不同升温速率(β=5、10、20、40 K/min)下羟基酪醇的热稳定性、分解动力学和贮存期。利用热重分析得到羟基酪醇在氮气氛围中不同升温速率(β)下的热分解曲线,运用3种多升温速率法Kissinger法、Friedman法和Flynn-Wall-Ozawa法以及2种单升温速率方法 Coats-Redfern法和Achar法进行动力学分析,计算热分解的表观活化能(Ea)和指前因子(A),且根据Ea和A推算羟基酪醇的贮存期。结果显示:羟基酪醇的热分解过程一步完成,在升温速率为10 K/min时,从260~409℃为羟基酪醇的主要失重阶段;TG曲线随着温度的升高而迅速出现陡峭明显的失重台阶,DTG曲线亦出现负值,且随着温度的升高而急剧下降,在305.2℃达到了DTG的峰值,此时达到最大热失重速率为-12.91%/min;升温速率的变化对羟基酪醇的分解有影响,随着速率的升高,羟基酪醇的热分解温度逐渐升高,热分解曲线略微向高温移动,呈现了分解滞后现象。羟基酪醇的热分解机制符合一维扩散(D1)模型。测得平均Ea为122.40 k J/mol,A为3.37×1010min-1。根据Ea和A可推断,在室温25℃下,羟基酪醇在氮气氛围下的理论贮存期为4~5年。     

油橄榄的化学组成和加工利用

研究油橄榄果和叶中的化学组成及其药效功能,国内外油橄榄的开发利用现状。针对国内油橄榄发展中存在的问题,提出应加强油橄榄叶的加工利用,尤其是油橄榄叶中多酚、黄酮及橄榄苦苷的分析研究和提取物精制技术的开发,为油橄榄叶提取物的生产和应用提供理论基础。     

羟基酪醇快速硝基化及产物波谱表征

【目的】为解决传统硝基化方法存在的易使羟基酪醇氧化和反应过程污染大等问题,建立一种对羟基酪醇进行快速硝基化反应的新方法,并解析反应产物结构,为邻二苯酚类化合物的硝基化及产物鉴定提供理论和数据支持。【方法】构建弱酸和室温环境,将亚硝酸钠与羟基酪醇充分混合进行快速硝基化反应,运用Uv-vis、FTIR、HPLC-MS、~1HNMR和~(13)CNMR等手段表征其硝基化产物。【结果】在室温和HAC-Na AC缓冲液(pH 3.8)条件下反应10 min,硝基羟基酪醇的转化率达99.5%;Uv-vis全波段扫描结果表明,硝基羟基酪醇的最大吸收波长分别为245、296和346 nm;FTIR结果表明,反应物羟基酪醇中的酚羟基在反应过程中未发生变化(波数3 359 cm~(-1)),而其反应产物中引入了硝基基团(波数1 557和1 405 cm~(-1));反应产物的HPLC-MS结果证实硝基羟基酪醇的相对分子质量为199,1HNMR和13CNMR结果证实了硝基基团键合于羟基酪醇酚羟基的对位。【结论】以温和的反应条件(室温、pH 3.8和10 min),使用价廉易得的亚硝酸钠调控羟基酪醇快速硝基化,及形成专一性对位取代产物的特征,使其在替代传统混合强酸制备硝基酚方面具有重要意义。     

HPLC研究油橄榄叶中橄榄苦苷的含量变化规律

研究了油橄榄叶中橄榄苦苷含量的变化规律,以及加工和提取条件对提取得率的影响;采用HPLC法测定橄榄苦苷的含量.对油橄榄叶中橄榄苦苷含量研究表明,一年生长期内有两个高峰期,分别是在2月份和5月份,其中2月份最高,两个低谷期则是在11月份和4月份;品种间差别很大,科拉地17.2 %,最低的配多灵仅为1.65 %;20年生较3年生的高.超声波辅助提取法较加热法提取得率高,自然阴干较烘干的提取得率高.     

开江县让油橄榄梦想开花

开江县经过40多年来的努力,油橄榄产业发展经历了引种试验(1974-1981年)、示范推广(1982—1991年)、巩固提高(1992—2000年)、规模发展(2001—至今)四个阶段,油橄榄品种资源得到有效保护,苗木培育初具规模,基地建设进展顺利,油橄榄产品开发向纵深发展,基本形成了“政府引导、业主开发、部门服务、农户参与”的运行机制,油橄榄产业在开江县开花结果。2018年,产油橄榄鲜果4110吨、橄榄油450吨、橄榄酒600吨、橄榄化妆品2吨,总产值3.2亿余元,林农人均从油橄榄产业上实现纯收入2000元以上。2018年开江县和开江油橄榄成功创建为“全国经济林产业区域特色品牌建设试点单位”和区域特色品牌。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.