鸭跖草多糖的提取及含量测定

采用正交设计优化鸭跖草多糖提取工艺.蒽酮-硫酸法测定不同生长环境鸭跖草茎、叶部位多糖的含量.试验结果表明,此方法简便,精密度及重现性较好,结果令人满意.     

Fluorescence shell: a novel view of sclereid morphology with the Confocal Laser Scanning Microscope

Confocal Laser Scanning Microscopy (CLSM) was used to observe sclereids from stems of Avicennia germinans and from fruits of two species of pear (Pyrus calleryana "Bradford" and P. communis "Red Bartlett"). The images obtained from thick (25 to 100 microm) free-hand sections were, in certain respects, far superior to those obtained by other, more invasive and time-consuming microscopic techniques upon which previous reports of sclereid morphology were based. The cell wall surfaces, including the "internal" surfaces of the branched pit canals and cell lumens, were much accentuated with the techniques we describe, resulting in a "fluorescence shell" image, meaning the cell wall did not stain all the way through but instead only at the inner and outer wall surfaces, including the edges of ramiform pits. By controlling the time of staining with 1% aqueous Safranin O, or by changing the number of optical sections used in extended focus images, it was possible to get either a conventional view of the cell wall structure or a unique, three-dimensional view of the elaborate cell interconnections. Similar fluorescence shell images of sclereids were also obtained using a periodic-Schiff (PAS) staining system, but the stain was not as specific to sclereid cell walls as was the Safranin O stain. Particularly with the use of a narrow range band pass emission filter of 505-530 nm, the Safranin O staining may be more specific to lignin than reported in the literature.     

Influence of distillation parameters on the extraction of Juniperus communis L. in vapour infused gin

The influence of distillation parameters on the extraction of flavour compounds from the gin botanical Juniperus communis L. using vapour infusion was investigated. The optimum mix of conditions to extract the highest levels of certain compounds was established using a 3³-factorial design. Quantification using solid-phase microextraction and gas chromatography coupled mass spectrometry, was performed measuring nine common flavour compounds. The greatest influence was the botanical ratio, whilst the least influential parameter was ethanol concentration for all compounds except terpinen-4-ol. Density functional theory calculations of quantitative structure–activity relationship properties for the flavour compounds were also undertaken to test for molecular influence on solvent extraction. The quantitative structure–activity relationship model showed the highest dipole moment for terpinen-4-ol and the lowest for γ-terpinene. © 2020 The Institute of Brewing & Distilling     

Toxin Content of Commercial Castor Cultivars

The castor plant Ricinus communis L. is the source of castor oil which has numerous uses and is a key chemical feedstock for an array of products from polymers to cosmetics. Although castor was once widely grown throughout the world, the presence of the toxic protein ricin has deterred the re‐introduction of this useful crop. In order to develop a low‐ricin or no‐ricin castor crop, a robust, accurate method for screening castor seed for ricin content is essential. In this study, we validated a sandwich enzyme‐linked immunosorbent assay for the detection of ricin and the homologous Ricinus communis agglutinin (RCA) in castor beans and screened a collection of castor lines including commercial varieties using this assay. Although the average content derived by extracting several seeds provided a fair representation of the ricin content for a given selection, there was enough seed‐to‐seed variation to justify determining the ricin/RCA content of individual seeds. Ricin levels observed ranged from 1.16 to 6.25 % by weight.     

固定化脂肪酶催化制备香叶树籽生物柴油研究

研究了Novozym 435和Lipozyme TLIM混合脂肪酶催化香叶树籽油制备生物柴油,2种酶按1:3质量比混合使用时,既可提高反应转化率,又可降低酶的使用成本.应用响应面优化法确定了固定化酶催化香叶树籽生物柴油的最优工艺参数,采用叔丁醇作为反应体系的溶剂,最优反应条件为反应温度38.5℃、甲醇与油摩尔比4:1、叔丁醇与油体积比1:1.5、酶用量为油质量的4%,此时反应转化率达90.09%.分析表明香叶树籽油的甘油三酯主要由短链脂肪酸甘油酯组成,生物柴油中原油的甘油三酯已完全转变成脂肪酸甲酯.     

Antioxidative Properties and Ability of Phenolic Compounds of Myrtus communis Leaves to Counteract In Vitro LDL and Phospholipid Aqueous Dispersion Oxidation

Antioxidant activities of Myrtus communis leaf phenolic compounds (McPCs) were investigated on 2,2′‐9‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS⁺?) and oxygen radical absorbance capacity (ORAC) tests or on oxidation of biological models, human low‐density lipoprotein (LDL) and phospholipid aqueous dispersion (l ‐α‐phosphatidylcholine stabilized by bile salts). Two extraction techniques, microwave‐assisted (MAE) and conventional (CE), were used to isolate McPCs, producing similar results of phenolic compound content. ABTS⁺? assay showed clearly that myrtle extracts exhibited a stronger scavenging effect than butylated hydroxyanisole and α‐tocopherol, with a slight advantage for myrtle CE extract. In ORAC assay, the both McPC extracts were similarly less effective than the pure compounds as caffeic acid and myricitrin (myricetin 3‐O‐rhamnoside) but stronger than butylated hydroxytoluene. Moreover, myrtle CE and MAE extracts, and myricitrin were able to inhibit similarly the production of conjugated dienes and to prolong the lag phase (Tlag) during Cu²⁺‐induced LDL oxidation with a dose‐response effect. The cryo‐electron microscopy observations on studied phospholipid dispersion stabilized by bile salts (BS) revealed the presence of bilayer vesicles and micelles. In 2,2′‐azobis (2‐amidinopropane) hydrochloride–induced phospholipid/BS oxidation, myrtle CE and MAE extracts gave similar effects to α‐tocopherol and caffeic acid but myricitrin showed a higher protective effect than myrtle extracts. We showed also that no synergic or additive effect between α‐tocopherol and myrtle extracts or caffeic acid in α‐tocopherol–enriched phospholipid/BS dispersion, but myricitrin showed an additive effect and thus promoted the total antioxidant activity. These data showed that myrtle extract could be used as potential natural antioxidants, food stabilizers, or natural health products.     

芦苇对太湖沉积物的影响

大型水生植物对沉积物中磷及相关因子的影响是个复杂的过程．一方面，其根系可从沉积物中吸收营养，另一方面，其根系向沉积物中释氧从而影响磷的释放和磷的生物地球化学循环．针对这一问题，采集了太湖芦苇区和无高等水生植物区沉积物，分析了磷、二价铁和二价锰，结果发现：1)芦苇区沉积物总磷(TP)含量在不同深度上均低于无高等水生植物区．2)2～4cm的沉积物亚铁(Fe^2 )富集峰最高，而二价锰(Mn^2 )的富集峰值在沉积物表层(0～2cm)，且其含量随着深度增加而减少．3)芦苇区沉积物Eh略大于无高等水生植物区．4)芦苇区沉积物中Fe^2 ／TP原子比小于无高等水生植物区，且深度增加而增加。     

大孔树脂分离纯化芦根中总酚酸的研究

目的：研究大孔树脂分离纯化芦根中总酚酸的工艺条件。方法：以芦根总酚酸的洗脱效果为考察指标,研究大孔树脂分离纯化的吸附性能及洗脱参数。结果：HPD500大孔树脂适宜芦根总酚酸的分离纯化,其再生能力良好,吸附过程符合Langmuir方程,洗脱液为pH8的80％体积分数乙醇溶液,获得纯度为0．98mg／g的总酚酸样品。结论：HPD500大孔树脂可用于芦根总酚酸的分离纯化。     

HPLC/DAD/ESI-MS analyses and anti-radical activity of hydrolyzable tannins from different vegetal species

In the present work, several tannin extracts from myrtle and pomegranate were analyzed and characterized using HPLC/DAD/ESI-MS methods. Both aqueous and hydroalcoholic myrtle leaf extracts were found to be rich in galloyl-glucosides, galloyl-quinic acids, ellagitannins and flavonoids. In these extracts we observed a predominance of galloyl-glucosides and galloyl-quinic derivatives with respect to ellagic derivatives; 87.14% and 12.86%, respectively, average gallic and ellagic derivatives with respect to total tannins content. In pomegranate extracts, substantial differences were found in polyphenol contents between peel and seed extracts with regard to the relative abundance of gallic and ellagic acid derivatives: 28.81% and 71.19%, respectively, as average total gallic and ellagic derivatives in peel extracts; 61.30% and 38.70%, in seed extracts. The antiradical properties were evaluated and compared to those of two commercial extracts of chestnut bark and grape seeds. The collected data could suggest the use of myrtle and pomegranate extracts as nutraceuticals and functional foods for their important antioxidant properties.     

鸭跖草抗氧化成分提取及其活性研究

采用1：2的氯仿：甲醇超声提取鸭跖草成分,并用石油醚、乙酸乙酯和正丁醇依次进行萃取,利用DPPH法、α-脱氧核糖法和铁氰化钾还原法进行抗氧化实验。同时与BHT和没食子酸（GA）2种合成抗氧化剂进行对照。结果显示乙酸乙酯提取物（EAF）具有较高的抗氧化活性。对其进行硅胶柱层析分离,得到6种纯化的组分（EAF1～EAF6）,其中EAF4具有最高的抗氧化活性,在实验所测4个浓度下,清除DPPH自由基能力均比BHT强,在10μg／ml和50μg／ml浓度时,比GA强。其清除羟自由基能力在所有测定浓度下均比2种人工合成抗氧化剂强。其还原能力在所有测定浓度下均比BHT强,但比GA弱。