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1.
The protected structure of -oxoacteoside (tomentoside A), 2-oxo-2-(3,4-dihydroxyphenyl)ethyl 3-O-(2,3,4-tri-O-acetyl--l-rhamnopyranosyl)-4-O-caffeoyl--d-glucopyranoside 14 was synthesized in 14% overall yield in 11 steps, starting from d-glucose for biological and medicinal studies of phenylpropanoid glycosides. The first step was the preparation of a 3-O-rhamnopyranosyl disaccharide sugar core 2 from a suitably protected rhamnosyl trichloroacetimidate 10 and glucose derivative (diacetone-d-glucose 1) in 71% yield. To the glucose moiety of this sugar core, several protection/deprotection procedures were performed sequentially to obtain a fully acetylated sugar core 7 with a 4-OH group on the glucose moiety, in 57% yield in five steps. Thereafter, to the 4-OH group of the glucose moiety, selective 4-O-caffeoylation was achieved by proton-transfer esterification with 3,4-di-O-allylcaffeic acid 16 to give the caffeoyl disaccharide 11 in 97% yield. Then, it was converted to trichloroacetimidate 13 for a glycosylation donor in 90% in two steps. Finally, anomeric glycosylation was conducted with 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl alcohol 19 with catalytic amounts of BF3·Et2O to give 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl 2,6-di-O-acetyl-3-O-(2,3,4-tri-O-acetyl--l-rhamnopyranosyl)-4-O-(3,4-di-allyloxycaffeoyl)--d-glucopyranoside 14 in 60% yield. Deprotected intermediates of compounds 2, 11, 14, and 19 which were obtained in high yield would be useful for biological and medicinal studies of phenylpropanoid glycosides.Part of this study was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April, 2002  相似文献   

2.
A modified synthetic method for phenolic-O-4 lignin substructure model dimers was developed involving protection of the phenolic hydroxyl group of acetophenons with benzoyl chloride, bromination with 4-dimethylaminopyridiniumbromide perbromide, condensation with phenols in the presence of 18-crown-6-ether, condensation with paraformaldehyde, reduction with NaBH4 and debenzoylation. This method results in shorter reaction times and increasing yields without the application of strict anhydrous and drastic conditions or chloric solvents. This alternative route could be applied to the-O-4 dilignol syntheses of four combinations of guaiacyl and syringyl derivatives.  相似文献   

3.
Bergmann  Ben A. 《New Forests》2003,25(3):185-199
Performance of Paulownia elongata, Paulownia fortunei, and Paulownia×Henan 1 was monitored at three sites in North Carolina between 1996 and 2000, and P. elongata clones were tested at an additional two sites. The primary objective was to define the potential for growing Paulownia in the state. Species and clones within species differed in survival and height and diameter growth whenever genotype was included as a treatment. P. elongata was superior at two and P. fortunei was superior at one of the three sites that included P. elongata, P. fortunei, and P.×Henan 1. Trees produced through vegetative means were more likely to survive and were taller and of greater DBH than seed produced trees. Mortality in trees produced from seed was greater for P. fortunei and P. ×Henan 1 than for P. elongata. Application of animal waste or different rates of nitrogen as inorganic fertilizer did not have a pronounced effect on tree survival and growth.  相似文献   

4.
The effect of sulfometuron (Oust) on the root growth of loblolly pine (Pinus taeda L.) seedlings was studied in the field and in two soil types in the greenhouse. In the greenhouse study sulfometuron was applied to the foliage only, the soil only, and to both foliage and soil at the rates of 0.10, 0.21, and 0.42 kg ai/ha. Twenty-eight days after application root growth significantly decreased for all methods of application and with increasing rates e.g., 0.10, 0.21, and 0.42 kg ai/ha sulfometuron reduced new root length by 42%, 53%, and 64%, respectively. Application in the field at the rate of 0.30 kg ai/ha resulted in a 68% reduction in root growth. However, by the end of the growing season treated seedling root and shoot biomass were 115% and 64% greater, respectively. To ensure earlier season survival the rate of sulfometuron applied should be kept at a minimum level that will allow both weed control and adequate root growth. Low rates would be particularly important during a dry planting season.  相似文献   

5.
The arid regions of India cover over 300,000 km2 and are spread over six States, mostly in the northwestern parts of the country. In spite of the hostile environmental conditions, several indigenous agroforestry practices are being practised in this region. The Central Arid Zone Research Institute (CAZRI) has made considerable progress in improving these indigenous practices and also developing new land use technologies some of which involve agroforestry approaches. Notable among these include sand-dune stabilization, shelterbelt plantations, tree planting techniques in difficult land forms, silvopastoral and agrisilvicultural systems, introduction and improvement of fruit trees and other indigenous trees, etc. Some of these technologies are adopted on a large scale by farmers in the arid zone of India, and have attracted international attention in other arid parts of the world. This paper is a summary of the results of these agroforestry initiatives of CAZRI.  相似文献   

6.
Ficus species are multipurpose trees well known by rural populations in Sahelian and Sudanian zones of Africa. Their uses are well documented but their amenability for vegetative propagation has not been extensively studied. This paper compares the rooting ability of stem and aerial root cuttings from thirteen Ficus species found in West Africa. It highlights the differences between species belonging to the sub-genera Sycomorus and Urostigma. The former show no capacity to propagate from cuttings whereas the latter, with epiphytic development, can be propagated by cuttings, although this capacity varies among species. Thus, F. thonningii, F. leprieurii and F. ovata are easily propagated, while F. platyphylla and F. elasticoides are propagated with difficulty. The rooting capacity also varies depending on the cutting material used. It decreases in the following order: long leafless hardwood cuttings (pole) > nodal cuttings > apical cuttings. Rooting potential increases when the cuttings are harvested towards the end of the dry season(March to May). Aerial root can be used for cuttings in all species of the sub-genus Urostigma. The capacity of root cuttings to regenerate is greatest when cuttings are collected at the beginning of the dry season (November). In this case, wound-induced adventitious roots arise at the basal end of the cutting while de novo buds are developed from the cambium at the distal end. The subsequent morphological development is identical to that of a stem cutting. These results clarify and allow the optimal use of the knowledge and methods developed by the indigenous people of the Sahel and could assist and promote fig tree (Ficus sp.) domestication in the dry tropics.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

7.
Sphingomonas paucimobilis SYK-6 produces unique and specific enzymes, such as-etherases,O-demethylases, and ring fission dioxygenases, for lignin degradation. Cleavage of arylglycerol--aryl ether linkage is the most important process in the lignin metabolic pathway ofS. paucimobilis SYK-6. We reported the genes (ligD, ligE, ligF) for enzymes that cleaved-aryl ether linkage of dimeric compounds in previous studies. In this study we synthesized the fluorescent high-molecular-weight lignin (UBE-DHP) by dehydrogenative polymerization. We investigated the-aryl ether cleavage ability of these enzymes produced in recombinantEscherichia coli. When UBE-DHP was incubated with LigF, 4-methylumbeliferone was released as a result of-aryl ether cleavage of O-methylumbelliferyl--hydroxypropiovanillone (compound III) incorporated in UBE-DHP. Here, we report that-etherase ofS. paucimobilis SYK-6 can be expressed inE. coli and is able to cleave the-aryl ether linkage in synthetic high-molecular-weight lignin.  相似文献   

8.
Pekka Rossi 《New Forests》1991,5(3):211-218
The influence of length of cuttings on establishment of a short rotation plantation was investigated over a period of two years using direct field planting of unrooted Populus Rasumowskiana cuttings. The longer the cuttings, the higher were the survival and dry mass production. Survival at the end of the second growing season varied from 75% to 97%. In two years, the two longest cutting lengths (40 cm and 50 cm) produced about 100 g dry mass per living cutting; but owing to the higher survival rate of the longest cuttings, there was a difference per area unit: 360 g/m2 for 40 cm and 400 g/m2 for 50 cm-long cuttings. The shortest (10 cm) cuttings produced only 115 g/m2.  相似文献   

9.
This article presents a validation of a method, proposed in Podlaski (2003), for estimating the degree of tree damage. This method belongs to a group of small-area methods. To estimate the degree of tree damage in individual P3 sub-blocks of the SINUS system of information on the natural environment, a classification based on the degree of defoliation was used. Spatial distribution of the degree of tree damage was estimated through unrestricted simple random sampling. The maximum total estimation error for proportions of fir and beech with a damage degree of zero, and also with second and third degrees jointly, reached a maximum of 35.6% for fir, and 33.8% for beech. P3 sub-blocks characterised by the highest proportion of the healthiest trees (at least 15% being undamaged trees) occurred in patches in the case of fir, and in larger, compact areas in the case of beech. Because spatial diversification in the health of fir, and to a smaller degree in the case of beech, occurs at small scales, small-area methods for estimating tree condition are necessary. An analogous scheme, combining small-area with large-area methods (utilising sub-blocks of the network of large-area systems in a small-area inventory, and establishing a common database), could be used on a wider scale; for example, by supplementing the program of estimating tree health carried out by the United Nations Economic Commission for Europe (Lorenz et al. 2002) with local inventories.  相似文献   

10.
The inhibitory effects of 17 samples prepared from Thailand plants on 5-reductase activity were examined. The acetone extract of leaves ofArtocarpus altilis showed potent 5-reductase inhibitory activity. Fractionation guided by 5-reductase inhibition led to the isolation of 2-geranyl-2,3,4,4-tetrahydroxydihydrochalcone from the acetone extract of leaves ofA. altilis. This compound showed more potent inhibitory effect (IC50=38M) than-linolenic acid known as a naturally occurring potent inhibitor.  相似文献   

11.
Ethyl acetate extracts ofCupressus lusitanica suspension cell cultures were examined for their biological activities (viz., tyrosinase inhibitory, antioxidant, and antimicrobial activities). The extract from elicitor-treated cells showed all of the biological activities, whereas the extract from cultures without elicitor was not bioactive to a discernible extent. The biological activities shown by the cell culture extracts were almost solely accounted for by-thuj aplicin contained in the extracts. These results suggest that the ethyl acetate extract ofC. lusitanica cells treated with the elicitor is a valuable bioactive source without isolation or purification of-thujaplicin.  相似文献   

12.
A new dibenzylbutyrolactone lignan 7.6-dihydroxybursehernin, together with six known lignans (pinoresinol, lariciresinol, secoisolariciresinol,-peltatin,-peltatin, 5-methoxypodophyllotoxin) were isolated from the methanol extracts ofLinum flavum var.compactum. The enantiomeric analysis of pinoresinol and lariciresinol isolated from the species, which are upstream lignans in the lignan biosynthetic pathway, indicated that they are not optically pure, which is in accordance with our recent findings on lignans occurring in other plant species.Parts of this report were presented at the 42nd Lignin Symposium, Sapporo, October 1997; and the 43rd Lignin Symposium, Fuchu, October 1998  相似文献   

13.
Five tannin-related compounds – gallic acid, flavogallonic acid dilactone, valoneic acid dilactone, gallagyldilactone, ellagic acid – were isolated from the heartwood of Shorea laeviforia, and the inhibitory activity of each against rat liver 5-reductase was evaluated. Valoneic acid dilactone and gallagyldilactone exhibited positive inhibitory activity, but gallic acid and ellagic acid did not. Flavogallonic acid dilactone stimulated 5-reductase activity, even though this compound is structurally similar to valoneic acid dilactone. The kinetic study of valoneic acid dilactone and gallagyldilactone indicated that the inhibitory behavior of 5-reductase were not competitive against the substrate (testosterone) and were partially competitive against the cofactor (NADPH). Additionally, double inhibition analysis of valoneic acid dilactone and NADP+ showed synergetic inhibition. These results suggested that neither valoneic acid dilactone nor gallagyldilactone can affect the binding of testosterone but that either compound could interact with an enzyme–NADP+ complex to inhibit 5-reductase.  相似文献   

14.
When (±)--oxo-guaiacylglycerol--(vanillic acid) ether (1) is degraded byFusarium solani M-13-1, the-ketone is initially reduced to giveerythro andthreo guaiacylglycerol--(vanillic acid) ethers (2), arylglycerol--aryl ethers, both of which are enantiomerically pure. The absolute configuration in each2 was determined by Mosher's method; the products were converted to,-di-(R)--methoxy--trifluoromethylphenylacetates (MTPA esters) (3) oferythro (-)- andthreo (+)-veratrylglycerol--(methyl vanillate) ethers (3), whose1H nuclear magnetic resonance (NMR) spectra were examined and compared with those of four di-(R)-MTPA ester (3) diastereomers from chemically synthesizederythro (±)-3 andthreo (±)-3. To assign the- and-MTPA-OCH3 peaks, the1H NMR scans of several compounds that have substructures of 3 and their 3,4,5-trimethoxyphenyl analogues were examined. When a racemic alcohol reacts with (R)-MTPA to give a pair of (R)-MTPA ester diastereomers, the value was defined as the absolute value of the difference in the1H chemical shifts of the peak between the diastereomers. It was found that the values of-MTPA-OCH3 were larger than those of-MTPA-OCH3 owing to a shielding effect of the veratryl ring located on the-MTPA-OCH3, and that the-MTPA-OCH3 peaks in the 3,4,5-trimethoxyphenyl compounds shifted downfield relative to those in the veratryl compounds. On the basis of the1h NMR data of (R)-MTPA esters, the absolute configuration of the four chemically prepared diastereomers (3) were determined. The catabolicerythro 3 [fromerythro (-)-3] andthreo 3 [fromthreo (+)-3] were identical to (R, S, R)-erythro 3 and (R, S, S)- threo 3, respectively. An hydrogen species in the fungal reduction would attack the-ketone fromre-face of both (R)-1 and (S)-1, givingerythro (S, R)-2 andthreo (S, S)-2, respectively.Part of this paper was presented at the 33rd Lignin Symposium, Tsukuba, November 1988  相似文献   

15.
The inhibitory effects of 102 methanol extracts of 40 mycelia, 9 culture fluids, and 53 fruiting bodies of 40 strains of Ganoderma lucidum on 5-reductase were investigated. The methanol extract of the fruiting body of each strain was found to show the strongest 5-reductase inhibitory activity among the extracts tested.  相似文献   

16.
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17.
Sugi (Cryptomeria japonica D. Don) and buna (Fugus crenata Blume) woods were treated with supercritical water (>374°C, >22.1 MPa) and fractionated into a water-soluble portion and a water-insoluble residue. The latter was washed with methanol to be fractionated further into a methanol-soluble portion and a methanol-insoluble residue. Whereas the carbohydrate-derived products were in the water-soluble portion, most of the lignin-derived products were found in the methanol-soluble portion and methanol-insoluble residue. The lignin-derived products in the methanol-soluble portion were shown to have more phenolic hydroxyl groups than lignin in original wood. The alkaline nitrobenzene oxidation analyses, however, exhibited much less oxidation product in the methanol-soluble portion and methanol-insoluble residue. These lines of evidence suggest that the ether linkages of lignin are preferentially cleaved during supercritical water treatment. To simulate the reaction of lignin, a study with lignin model compounds was performed;-O-4-type lignin model compounds were found to be cleaved, whereas biphenyl-type compounds were highly stable during supercritical water treatment. These results clearly indicated that the lignin-derived products, mainly consisting of condensed-type linkages of lignin due to the preferential degradation of the ether linkages of lignin, occurred during supercritical water treatment.This study was presented in part at the 45th lignin symposium, Ehime, Japan, October, 2000; and the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1988  相似文献   

18.
Sugi (Cryptomeria japonica D. Don) wood was treated with supercritical water (374°C, 22.1MPa), and fractionated into the water-soluble portion, the methanol-soluble portion, and the methanol-insoluble residue. The methanol-soluble portion mainly consisted of the lignin-derived products. To characterize the compounds in the methanol-soluble portion, gel permeation chromatographic (GPC) and gas chromatographic-mass spectrometric (GC-MS) analyses were performed. The GPC analysis indicated that the methanol-soluble portion contained lignin-derived monomeric and dimeric products. GC-MS analysis detected 31 products which were expected to be monomeric compounds, and 18 of these were identified to be guaiacol, methylguaiacol, ethylguaiacol, vinylguaiacol, eugenol, propylguaiacol, vanillin, cis-isoeugenol, homovanillin, trans-isoeugenol, acetoguaiacone, propioguaiacone, guaiacylacetone, 2-methoxy-4-(1-hydroxypropyl)phenol, homovanillic acid, 2-methoxy-4-(prop-1-en-3-one)phenol, coniferyl aldehyde, and ferulic acid. In addition, 22 dimeric products were detected, and 4 of these were believed to be compounds with biphenyl type (5-5), diphenylethane type (-1), stilbene type (-1), and phenylcoumaran type (-5) structures. These results clearly indicated that the methanol-soluble portion included various monomeric and dimeric compounds produced as a result of the cleavage of ether linkages and propyl chains of lignin.  相似文献   

19.
To elucidate the formation and chemical structures of water-soluble material in acid-soluble lignin (ASL), lignin aromatic nuclei model compounds of creosol (I) and 5-methoxycreosol (II) were reacted with xylose or xylan in the presence of apocynol as a counterpart for condensation in 72% sulfuric acid (SA). The reaction of I gave mainly condensation product. However, the condensation reaction of II with apocynol was suppressed because of steric hindrance from the methoxyl group, and II yielded a C-xyloside after refluxing in 3% SA together with condensation products. To obtain information on CHCl3-soluble material in ASL, model compounds of arylglycerol--aryl ethers with guaiacyl (VIII) and syringyl (X) nuclei were treated by the Klason procedure. VIII gave only insoluble polymerized product, while X gave insoluble polymerized product and CHCl3-soluble low molecular weight products, which were dissolved in 3% SA. These results prove earlier views that water-soluble material in ASL consists of condensation products formed from syringyl lignin and monosaccharide units in hemicellulose. In addition, the CHCl3-soluble material in ASL appears to be composed of low molecular weight degradation products from SA treatment of Klason lignin with the syringyl nucleus.Part of this report was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001 and at the 47th Lignin Symposium, Fukuoka, October 2002, and was reviewed in Mokuzai Gakkaishi (2002) 48:55–62  相似文献   

20.
Wind velocity, vertical stand structure and seasalt distribution were measured at various heights inside a plantation of coastal pine forest, with thinning and unthinning, to assess whether any relationships exist between the wind profile, stand structure and seasalt distribution in the coastal pine forest. The vertical stand structure, i.e., optical stratification porosity (OSP), which is defined as vertical distribution of the proportion of sky hemisphere not obscured by tree elements inside a forest stand, was determined for each height by computer analysis of digital images taken with a hemispherical lens. The distribution of OSP in the coastal forest follows the Lambert-Beer's law with absorbency coefficient (). The relative windspeed within canopy can be described using the exponential form with the attenuation coefficient (). The sea-salt was collected using salt gauze (a surgical dressing of loosely woven cotton) both inside and outside the coastal forest, and the distribution of sea-salt within canopy was also in accordance with an exponential function. The relationships among windspeed, OSP and sea-salt indicate that the distributions of both sea-salt and windspeed within canopy were very closely correlated with the distribution of OSP. A linear relationship between OSP and sea-salt has been found. Additionally, linear regression between coefficients and has been obtained as well. Based on these relationships between OSP, wind and sea-salt in the coastal forest, the sea-salt distribution and wind profile within the canopy of the coastal forest can be predicted according to OSP. These results may therefore be useful in analyzing the effects of sea-salt on vegetation and evaluating the filter functions of coastal forests.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

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