The hydrophobic and water-repellent properties of wattle bark extractives

Summary Based on the fact that bark is an almost perfect water barrier and assuming that bark is impregnated with materials which aid in rendering it impermeable to water, the hydrophobic and water-repellent properties of several bark extractives were investigated. Products obtained after extraction with polar and non-polar solvents showed widely different properties. Some were extremely hydrophobic and water-repellent with a water-solid-air contact angle higher than 100°. These were the products obtained from extraction with benzene and mineral turpentine. Alcohol and acetone extractives had contact angles as low as 23° but coatings from some of these materials nevertheless had a high efficiency as water barriers. The efficiency of the various extractives as water repellents or water barriers was determined by coating wood with 10 per cent solutions of the extractives in different solvents and determining the extent to which water could be prevented from being absorbed and causing swelling of the wood and thereby reduce the dimensional changes of the wood. The extractives obtained with nonpolar solvents were extremely efficient as true water repellents while the polar aleohol extracts were far better than could be expected from their almost hydrophilic properties. Nature has therefore provided for hydrophilic film-formers combined with hydrophobic materials which act as a double line of defence against water absorption. The hydrophilic extractives, in addition, act as a bridging agent between the strongly hydrophobic extractives and the hydrophilic cell wall material.Since some of the extractives from wattle bark have excellent hydrophobic properties, and since this bark is available in large quantities as a waste product after tannins have been extracted, the utilization of certain wattle bark extractives as water repellents could be economically attractive.     

Therapeutic orchids: traditional uses and recent advances — An overview

Orchids have been used as a source of medicine for millennia to treat different diseases and ailments including tuberculosis, paralysis, stomach disorders, chest pain, arthritis, syphilis, jaundice, cholera, acidity, eczema, tumour, piles, boils, inflammations, menstrual disorder, spermatorrhea, leucoderma, diahorrhea, muscular pain, blood dysentery, hepatitis, dyspepsia, bone fractures, rheumatism, asthma, malaria, earache, sexually transmitted diseases, wounds and sores. Besides, many orchidaceous preparations are used as emetic, purgative, aphrodisiac, vermifuge, bronchodilator, sex stimulator, contraceptive, cooling agent and remedies in scorpion sting and snake bite. Some of the preparations are supposed to have miraculous curative properties but rare scientific demonstration available which is a primary requirement for clinical implementations. Incredible diversity, high alkaloids and glycosides content, research on orchids is full of potential. Meanwhile, some novel compounds and drugs, both in phytochemical and pharmacological point of view have been reported from orchids. Linking of the indigenous knowledge to the modern research activities will help to discover new drugs much more effective than contemporary synthetic medicines. The present study reviews the traditional therapeutic uses of orchids with its recent advances in pharmacological investigations that would be a useful reference for plant drug researches, especially in orchids.     

柚木的植物化学与药理学研究进展

柚木Tectona grandis 树干通直,木材纹理优美,是世界著名的速生珍贵用材树种。树体含有 甲基蒽醌、拉帕醌和脱氧拉帕醌等活性成分,可抵抗白蚁和真菌侵害。柚木树皮、叶片、心材等部位富 含萘醌、蒽醌和类异戊二烯醌等次级代谢产物,以及三萜类、类固醇、木酚素、脂肪酯和酚类等植物化 学物质。药理上,柚木被证实具有抗氧化、消炎、解热、细胞毒性、镇痛、降血糖、伤口愈合等多重功 效。文章着重介绍柚木的植物化学和药理研究方面的最新进展,以及其后续开发利用潜力。     

植物源提取物木材防腐剂的研究现状与展望

自然界的许多植物中均含有抑菌性和防虫性物质, 如果将这部分资源开发并用于木材防腐, 来替代和部分替代现有的合成类木材防腐剂, 将会促进人居和生态环境的改善。随着发展绿色、环保型木材保护技术的呼声越来越高, 世界范围内的很多学者广泛开展了植物提取物木材防腐剂的研究。文中对国内外植物源木材防腐剂的研究及其在木材和木制品保护中的利用进行概述, 并对今后的植物源木材防腐剂研究进行展望。     

Micromorphology and topochemistry of extractives in Scots pine and Norway spruce thermomechanical pulps: a cytochemical approach

Due to the increasing demand for Norway spruce as prime raw material for high-yield pulping, recent interest has focused on Scots pine as an alternative. However, the intrinsic properties of Scots pine, particularly the high amounts of extractives and the fiber properties, have been considered a disadvantage for thermomechanical pulping. A study was therefore conducted on the variations in the spatial distribution and redistribution of lipophilic extractives in spruce and pine wood and thermomechanical pulp (TMP) using cytochemical staining methods and chemical analysis. Chemical analyses showed chips from pine thinnings and sawmill slabs to contain three to five and two to three times, respectively, more extractives than found in spruce; in particular, the amount of triglycerides differed significantly. Results from staining techniques on the abundance and distribution of extractives (i.e., fats) between pine and spruce correlated with amounts detected by Fourier transform infrared spectroscopy and gel permeation chromatography. Cytochemical observations revealed information pertaining to species-specific distribution and redistribution of extractives among TMP fines and fibers and indicated the presence of a molecular film of extractives. Results indicate that the high concentrations of extractives in pine ray parenchyma are released during TMP processing and are redistributed onto the surfaces of the pulps, negatively affecting energy usage during primary refining.     

厚朴酚与和厚朴酚类化合物药效的分子机制

厚朴中的主要活性成分厚朴酚与和厚朴酚表现出高效低毒的药理活性,具有开发分子药物的潜力。为给此类成分分子药理的深入研究提供参考和依据,综述了近20年来国内外关于厚朴酚、和厚朴酚类化合物药效分子机制方面的研究情况和研究进展;并在分析分子几何构象、电子结构、电化学反应行为及比较药理活性差异的基础上,对厚朴酚、和厚朴酚类化合物的构效关系和作用的生物靶分子进行了探讨。     

Production of phenols and charcoal from bagasse by a rapid continuous pyrolysis process

Summary Tar and charcoal could be produced in high yields from bagasse by applying a rapid continuous pyrolysis process at a relatively low temperature. The ether extractives of the pyrolytic tar and oil amounted to 9.4% based on bagasse. Phenols represented 79% of these extractives. Gas chromatographic separation showed that guaiacol and its derivatives constituted 38% of the identified simple phenols. There were much smaller amounts of syringol and none at high pyrolysis temperatures. Depithing did not reduce the ash content of the charcoal, but it yielded an environmentally clean charcoal containing practically no sulfur or nitrogen. It was necessary to remove the fine particle size fraction of the bagasse after grinding in order to reduce the ash content of the charcoal. The carbon content of the charcoal increased rapidly with increasing temperature, and reached 96% at 720°C. The charcoal had a remarkably high adsorption capacity despite the fact that it had not been subjected to any activation treatment.The first two authors wish to express their thanks to the Institut für Holzchemie, Hamburg for providing facilities during this work and to the Alexander von Humboldt-Stiftung, and the Deutsche Forschung Gemeinschaft for their financial support     

Radial patterns of carbon isotopes in the xylem extractives and cellulose of Douglas-fir

Heartwood extractives (nonstructural wood components) are believed to be formed from a combination of compounds present in the adjacent sapwood and materials imported from the phloem. The roles of local compounds and imported material in heartwood formation could have important implications for the wood quality of species having naturally durable wood. Stable isotope composition (delta(13)C) was analyzed to assess radial variation in sapwood extractives, and to estimate the relative importance of adjacent sapwood extractives and imported photosynthate in the formation of heartwood extractives. Cellulose and extractives from the outer 39 annual rings of six Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees were isolated and their delta(13)C composition determined. Although the extractives and the cellulose showed different absolute delta(13)C values, the patterns of change over time (as represented by the annual rings) were similar in most cases. Within an annual ring, carbon isotope ratios of extractives were correlated with the cellulose isotope ratio (R2 = 0.33 in sapwood, R2 = 0.34 in heartwood for aqueous acetone-soluble extractives; R2 = 0.41 in sapwood for hot-water-soluble extractives). These data suggest that some sapwood extractives are formed when the wood ring forms, and remain in place until they are converted to heartwood extractives many years later. Sapwood extractives appear to be important sources of materials for the biosynthesis of heartwood extractives in Douglas-fir.     

沉香香气物质研究进展

香气是沉香质量等级的重要感官评价特征,赋予了沉香独特而优异的品质。沉香香气物质主要包括色酮及其衍生物、萜烯类和芳香族类化合物等。文中对沉香香气物质的检测方法、香气组分分析、生物合成代谢途径和关键酶、影响香气物质形成的因素以及相关合成的分子调控机制进行概述,并针对现阶段研究存在的问题提出研究展望,旨在为沉香香气物质研究提供理论参考。     

Extractives of muirapiranga (<Emphasis Type="Italic">Brosimun</Emphasis> sp.) and its effects on the vibrational properties of wood

The potential of muirapiranga (Brosimun sp.) as a substitute material for violin bows was estimated in terms of vibrational properties, and the influence of extractives on the vibrational properties was examined. The loss tangent of muirapiranga was somewhat higher and the specific dynamic Young’s modulus was rather lower than the respective values for pernambuco, which is regarded as the best material for violin bows. Therefore, muirapiranga is a poorer bow material in terms of vibrational properties. Impregnation of crude extractives from muirapiranga decreased the loss tangent of other wood specimens. The main compounds of the extractives were identified as xanthyletin and luvangetin. Impregnations of isolated xanthyletin and commercially available methoxsalen, which was tested as an analogue of luvangetin, markedly decreased the loss tangent of other wood specimens. Methoxsalen and xanthyletin differ from conventional loss tangent-decreasing substances, namely protosappanin B and hematoxylin, in terms of water insolubility and the absence of hydroxyl groups. From the similarity in molecular characteristics of loss tangent-decreasing substances found so far, restriction of molecular motion due to an impregnated substance in the wood matrix is suggested as one loss tangent-decreasing mechanism.     

人工林米老排木材化学成分及其在树干高度上的变异

采用我国木材化学成分分析国家标准,对人工林米老排木材化学成分进行了测定和研究分析.结果表明:人工林米老排木材冷水抽提物含量和热水抽提物含量分别为2.67%和3.12%,1%NaOH抽提物含量为17.08%,纤维素含量为47.49%,综纤维素含量为80.42%,木素含量为28.80%,pH值为5.44;木材冷水抽提物和综纤维素含量在树干的不同高度上略有差异,但方差分析检验,差异不显著,热水抽提物、1%NaOH抽提物、纤维素和木素含量在树干的不同高度上差异显著,达到1%显著性水平;由树基往上,热水抽提物含量略呈两端高、中间低的趋势,冷水抽提物、1%NaOH抽提物和木素的含量逐渐降低,综纤维素含量和木材pH值逐渐升高;纤维素含量在树干上的分布规律为中间高、两端低,而且从树干中部往上的降低幅度较大.     

The hydrophobic properties of bark extractives

Summary The hydrophobic properties of benzene-soluble extractives from the bark of Pinus radiata were studied by determining the water-solid-air contact angle and the resistance to water penetration.The material contained in the bark extract possessed wax-like and film-forming properties. It was highly hydrophobic with a contact angle with water of about 98°. Wood samples were impregnated with bark extract in order to study the ability of the hydrophobic bark extractives to prevent preferential wetting with water and the displacement of the impregnant from the hydrophilic wood surface. The wax-like material deposited from the bark extracts showed a remarkable affinity for wood as revealed by the high degree of resistance to water penetration and wetting of the treated wood even after several wetting-drying cycles which otherwise tend to break down the bonds and adhesion between a hydrophilic solid and a hydrophobic coating.Hydrophobic or film-forming additives did not improve the ability of bark extractives to protect a hydrophilic solid from water. The properties of the bark extractives as a water repellent and a water barrier could therefore be assumed to be as near perfect as possible.Nature seems to have solved the problem of producing one single, although complex, material with two properties which are extremely difficult, maybe impossible, to combine in a single synthetic material: one of high affinity for a hydrophilic solid and another of extreme water repellency and resistance to water.The in situ conditions prevailing in the bark tissue, combining bark extractives and cell walls of various anatomical structures, must therefore represent a rather unique and for this specific purpose highly efficient two-phase hydrophobic-hydrophilic solid system.The authors would like to express their appreciation to Kalley Timber Development Corporation for the close co-operation and support for our research on bark products and would also like to thank Lewis and Everitt, Poly-Resin Products Ltd., Taeuber and Corssen, Farbenfabriken Bayer AG, Scado-Archer-Daniels, Triton Chemicals and Rohm and Haas for supplying samples and information.     

水分平衡及非平衡状态下木材细胞壁中吸着水的介电弛豫(英文)

本文较系统地归纳了迄今为止有关绝干状态木材细胞壁构成主成分和抽提成分 ,水分平衡及非平衡状态下木材细胞壁中吸着水的介电弛豫方面的研究 ,并对今后的研究方向作了讨论。旨在使木材科学工作者对该领域的研究有一个全面的了解 ,并能够从中得到启迪和借鉴 ,把木材中吸着水的介电弛豫研究提高到一个更新 ,更高的层次上     

Lipophilic extractives in different tree fractions and forestry assortments of Pinus sylvestris due for thinning or final cutting

The objectives were to determine the content and composition of lipophilic extractives, particularly fatty and resin acids, in three Scots pine trees from each of two stands in northern Sweden, one that was due for thinning and one due for final cutting. Extractives content of branches, needles, barks, stem discs from branch whorls, and sapwood and heartwood samples from various heights was measured. Fractions had very different concentrations and distributions of extractives due to differences in the composition of tissues. The needles had the highest total extractive concentration (around 150?kg/ton d.w.), followed by the branches, bark, timber from the final cut stand, and then the pulpwood and timber from the thinning stand. The final cut stand generally provided higher yields of extractives in assortments per hectare than the thinning stand; the difference was five-fold for timber, three-fold for whole trees, two-fold for branches, needles and bark and similar for pulpwood. This information on the content and composition of extractives in different tissues, and the dependence of these quantities on tree age could be used together with information on conventional stand data such as tree numbers and dimensions to guide the selection and management of feedstocks for biorefineries.     

我国树木提取物开发利用现状与展望

树木提取物在植物提取物中占据了主要地位。树木提取物的开发利用是森林资源可持续高效利用的一个重要组成部分。树木提取物有效成分卓越的化学活性和生物活性,使其在化工、医药、食品、农药等众多行业被广泛利用。我国树木提取物开发利用的研究与产业开发取得迅速的发展。当前该领域面临新的机遇和挑战,必须加强技术创新研究、宏观性指导、资源保护与发展、产品标准化建设,才能促进该行业的健康发展。     

An ethnopharmacological study on common privet (Ligustrum vulgare) and phillyrea (Phillyrea latifolia)

Ligustrum vulgare and Phillyrea latifolia leaves were well known in the Mediterranean historical medicine for their oropharyngeal anti-inflammatory effects. At the present time a popular phytotheraputical use of these species remains only in a few isolated southern European areas. Phytochemical and phytopharmacological studies of the methanolic extractives of their leaves were carried out. Flavonoidic fractions as well as different isolates, apigenin and luteolin derivatives showed significant in vitro complement inhibiting effects on the classical pathway of the complement system. A possible phytoceutical utilisation of the aerial parts of these species could represent (especially regarding the genus Phillyrea) an interesting perspective for many semi-arid Mediterranean regions.     

紫苏子皮提取物中抗氧化性成分及作用研究

对紫苏子皮的成分及性质进行研究，用实验方法证明该皮含有丰富的黄酮及多酚类化合物，具有防止油脂氧化的功能。可用于代替化学合成抗氧化剂。不仅无毒，而且不具有保健作用。     

长白落叶松提取物对木材防腐作用的研究

以长白落叶松心材、边材及树皮为原料,分别用乙醚、氯仿、丙酮、甲醇和水5种溶剂对其进行提取,采用滤纸片法研究了不同溶剂提取物分别对白腐菌和褐腐菌的抑菌性能,发现心材的甲醇提取物和丙酮提取物对白腐菌有较好的抑制效果,树皮的水提取物对2种菌都有较好的抑制效果.并研究了这两种提取物在室内对木材的防腐性能,借助扫描电子显微镜(SEM)照片观察了木材腐朽后菌丝生长的情况,与常用木材防腐剂酸性铬酸铜(ACC)进行了对比,结果显示:心材的甲醇提取物对白腐菌的抑制效果较好;而树皮的水提取物对褐腐菌抑制效果较好.     

木材光降解机理及研究进展

木材受紫外可见光照射后易发生降解, 表面的材色和力学性能都会下降, 大大影响木材的使用价值和美学特点。文中针对木材光降解机理进行了讨论, 在提出木质素是木材光降解中关键组分的同时, 强调了抽提物对木材光变色的具体影响; 通过详细叙述光降解过程中木材发生的化学变化, 进一步表明该过程中自由基中间体的生成和新的发色团的产生; 系统总结了影响木材光降解的主要因素, 并提出防治木材表面光降解的技术手段。     

Radial distribution of thujaplicins in old growth and second growth western red cedar (Thuja plicata Donn)

Summary Radial distribution of thujaplicins in western red cedar (Thuja plicata Donn) trees of varying ages was studied in order to assess relative decay resistance of their wood. Samples were extracted with ethanol: benzene (1: 2), and the extractives were analyzed for thujaplicin codtent by a new method utilizing capillary gas chromatography of their methylated derivatives. The combined concentration of thujic acid and methyl thujate was also determined for each sample. Distribution of extractives, thujaplicins and thujic acid, generally increased from pith to outside heartwood, then decreased in the sapwood. Maximum extractive and thujaplicin contents were also related to tree age. This suggests that products made from the wood of younger trees will be less resistant to decay than similar products made from the wood of old trees.