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1.
MD. Atiar Rahman Takeshi Katayama Toshisada Suzuki Takashi Nakagawa 《Journal of Wood Science》2007,53(2):161-167
Steps leading to the biosynthesis of syringyl lignans and tetrahydronaphthalene and naphthalene lignans, especially the formation
of the C2–C7′ linkage, have not been elucidated. Lyoniresinol is a typical syringyl lignan, as well as a tetrahydronaphthalene
lignan found in Lyonia ovalifolia var. elliptica. To demonstrate the biosynthetic pathway for (+)-lyoniresinol, three putative biosynthetic intermediates of lyoniresinol,
syringaresinol, 5,5′-dimethoxylariciresinol, and 5,5′-dimethoxysecoisolariciresinol, were isolated from wood. The identity
of the putative intermediates was confirmed by spectroscopic analyses, as well as by comparison of spectral and chromatographic
data with those of authentic samples previously synthesized. The stereochemistry (enantiomeric composition and absolute configuration)
of the isolated lignans were determined as (±)-syringaresinol, (8S,8′S)-(−)-5,5′-dimethoxylariciresinol [46% enantiomeric excess (e.e.)], (8S,8′S)-(+)-5,5′-dimethoxysecoisolariciresinol (91% e.e.), and (8R,8′R)-(+)-lyoniresinol (42% e.e.). The absolute configurations of (+)-and (-)-5,5′-dimethoxylariciresinols, and (+)-and (-)-5,5′-dimethoxysecoisolariciresinols
were determined by their synthesis (catalytic reduction) from (8R,8′R)-(+)-and (8S,8′S)-(-)-syringaresinols and by subsequent chiral high-performance liquid chromatography analysis.
This report was presented at the 55th Annual Meeting of the Japan Wood Research Society, Kyoto, March 2005 相似文献
2.
MD. Atiar Rahman Takeshi Katayama Toshisada Suzuki Yuka Yoshihara Takashi Nakagawa 《Journal of Wood Science》2007,53(2):114-120
To clarify the biosynthetic pathway for syringyl lignans, especially syringyl tetrahydronaphthalene lignans and formation
of the C2–C7′ linkage, production of (+)-lyoniresinol (LYR) and its predicted intermediates [syringaresinol (SYR), 5,5′-dimethoxylariciresinol
(DMLR), and 5,5′-dimethoxysecoisolariciresinol (DMSLR)] in Lyonia ovalifolia var. elliptica was investigated by means of feeding experiments with radiolabeled precursors. Following individual administration of l-[U-14C]phenylalanine (Phe), [8-14C]sinapyl alcohol (SA), and [8,8′-14C]SYR to excised young shoots of L. ovalifolia and their subsequent metabolism, free [14C]lignans and [14C]lignan glycosides were extracted with methanol from stems and leaves and were divided into ethyl acetate-soluble fractions
(lignans) and aqueous fractions (lignan glycosides), respectively. Using a combination of xylanase, cellulase, and β-glucosidase, the glycosides were hydrolyzed to liberate [14C]lignans as aglycones. l-[U-14C]Phe was incorporated into (+)-[14C]SYR [stem 0.38%, 8% enantiomeric excess (e.e.)], (−)-[14C]SYR (leaves 2.75%, 72% e.e.), (+)-[14C]DMLR (stem 0.07%, 18% e.e. and leaves 0.009%, 58% e.e.), (−)-[14C]DMSLR (stem 0.03%, 46% e.e. and leaves 0.05%, 20% e.e.), (+)-[14C]LYR (leaves 0.013%, 22% e.e.) and glycosides of (+)-[14C]LYR (stem 0.036%, 50% e.e.) in 24h. Based on the percent incorporation and enantiomeric composition of the lignans, the
biosynthetic pathway of (8R,8′R)-(+)-LYR was proposed as follows: a nonselective dehydrogenative dimerization of sinapyl alcohol yields (±)-SYR, which is
reduced with low specificity to give (8R,8′R)-(+)-DMLR. This is cyclized to directly give (+)-LYR as well as reduced again to (8R,8′R)-(−)-DMSLR. Although further transformation of (−)-DMSLR also leads to the formation of (+)-LYR, cyclization could be a main
pathway for (+)-LYR biosynthesis.
This report was presented at the IAWPS 2005 International Symposium on Wood Science and Technology, Yokohama, November 2005 相似文献
3.
The alkaloidal fraction from Himatanthus lancifolius barks demonstrated a broad-spectrum in vitro antimicrobial activity for most of the Gram (+) and Gram (-) tested microorganisms. 相似文献
4.
Rahman MM Lopa SS Sadik G Harun-Or-Rashid Islam R Khondkar P Alam AH Rashid MA 《Fitoterapia》2005,76(7-8):758-761
O-Methylmoschatoline, liriodenine and 3,4-dihydroxybenzoic acid isolated from the barks of Cananga odorata showed antibacterial activities against a number of Gram (+) and Gram (-) bacteria. The compounds also showed antifungal and cytotoxic activities. 相似文献
5.
To clarify the biosynthesis of syringyl lignans and lignan formation by stereoselective coupling of monolignols, formation of (+)-syringaresinol and (+)-pinoresinol inLiriodendron tulipifera were investigated by means of feeding experiments. Following individual administration ofl-[U-14C]phenylalanine and [8-14C]sinapyl alcohol to excised shoots ofL. tulipifera and their subsequent metabolism for 3h, free [14C] lignans and [14C] lignan glucosides were extracted from both of the stems and leaves with methanol and divided into an ether fraction and an aqueous one, respectively. The glucosides were hydrolyzed by a combination of cellulase and-glucosidase to liberate [14C]lignans as aglycones.l-[U-14C]Phenylalanine was incorporated into free (+)-[14C]syringaresinol and its glucosides; the (+)-[14C]syringaresinols in the stems and leaves had 52% enantiomeric excess (% e.e.) and 42% e.e., respectively; and the (+)-[14C]syringaresinol aglycones from the glucosides in the stems and leaves had 20% e.e. and 22% e.e., respectively. Furthermore, [8-14C]sinapyl alcohol was incorporated into (+)-[14C]syringaresinol and its glucosides in the stems. These results suggest that the (+)-enantiomer of syringaresinol was enantioselectively formed from two molecules of sinapyl alcohol inL. tulipifera followed by transformation into the (+)-syringaresinol glucosides, accompanying the formation of racemic syringaresinol by nonselective coupling and the subsequent transformation of the racemate into their glucosides.l-[U-14C]Phenylalanine was incorporated also into free (+)-[14C]pinoresinol and its glucosides with 12%–42% e.e.Part of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society, Kochi, April 1997 相似文献
6.
A new arylnaphthalene lignan, named furfuracin (1), was isolated from the leaves of Knema furfuracea (Myristicaceae), whereas 7 known compounds including (+)-trans-1,2-dihydrodehydroguaiaretic acid, fragransin A2, biochanin A, gingkolic acid, anarcardic acid, 2-hydroxy-6-(12-phenyldodecyl)-benzoic acid and 2-hydroxy-6-(12-phenyldodecen-8′Z-yl)-benzoic acid were obtained from its stems. The structure of the new lignan was established by analysis of spectroscopic data (UV, IR, MS and NMR). 相似文献
7.
Takanori Imai Sousuke Inoue Naomi Ohdaira Yasuyuki Matsushita Rie Suzuki Mariko Sakurai José Manoel Henriques de Jesus Salete Kiyoka Ozaki Zenesio Finger Kazuhiko Fukushima 《Journal of Wood Science》2008,54(6):470-475
Heartwood extracts from Amazonian trees cumaru-ferro (Dipteryx odorata), jatoba (Hymenaea courbaril), and guarita (Astronium lecointei) exhibit antioxidant activities comparable with that of α-tocopherol, a well-known antioxidant. This article reports the characterization of the antioxidant compounds in the extracts
of the three heartwoods. Silica gel column chromatography of the cumaru-ferro EtOAc extract yielded (−)-(3R)-7,2′,3′-trihydroxy-4′-methoxyisoflavan and (+)-(3R)-8,2′,3′-trihydroxy-7,4′-dimethoxyisoflavan. Silica gel column chromatography followed by preparative high-performance liquid
chromatography of the jatoba EtOAc extract yielded (−)-fisetinidol and (+)-trans-taxifolin. Chemical structures were assigned using electron-ionization mass spectrometry, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy including nuclear Overhauser effect spectroscopy (NOESY), as well as optical
rotation and circular dichroism. Gas chromatography-mass spectrometry demonstrated that the isolated compounds were predominant
in the EtOAc extracts. In the guarita EtOAc extract, catechin and gallic acid were identified by comparing their retention
times and mass fragmentation patterns with those of authentic samples. Antioxidant activity determined by the 1,1-diphenyl-2-picrylhydrazyl
assay demonstrated that all these compounds had activities comparable with that of α-tocopherol.
Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007 相似文献
8.
Fumio Kawamura Yoshinari Kikuchi Tatsuro Ohira Mitsuyoshi Yastagai 《Journal of Wood Science》2000,46(2):167-171
The phenolic constituents of the roots ofTaxus cuspidata (Japanese yew) were investigated. Four lignans, [(+)-taxiresinol (1), (+)-lariciresinol (2), (–)-secoisolariciresinol (3), and (+)-pinoresinol (4)] were isolated and identified. The assignment of proton and carbon atoms for the lignans were finally solved by one- and twodimensional-nuclear magnetic resonance spectra. The enantiomeric excess of these lignans were determined by chiral high-performance liquid Chromatographic analyses. (+)-Lariciresinol and (–)-secoisolariciresinol were optically pure; (+)-taxiresinol was also suggested to be optically pure, although (+)-pinoresinol was not (77% enantiomeric excess). 相似文献
9.
The essential oil of Achillea clavennae was investigated for its antibacterial activity against some respiratory tract pathogens. Maximum activity was observed against Klebsiella pneumoniae and penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae. The oil also exhibited strong activity against Gram (-) Haemophilus influenzae and Pseudomonas aeruginosa. Gram (+) Streptococcus pyogenes was the most resistant to the oil. 相似文献
10.
Thymelaeaceae plants produce dextrorotatory dibenzylbutyrolactone lignans, which are opposite enantiomers to the lignans isolated from other plants (e.g.,Forsythia spp.). In our previous paper, (–)-pinoresinol (74% enantiomer excess), (+)-matairesinol (optically pure), and (+)-wikstromol (optically pure) were isolated fromWikstroemia sikokiana (Thymelaeaceae). In the present investigation, a survey of lignans and the determination of their enantiomeric compositions were continued. Four lignans, (–)-lariciresinol, (–)-secoisolariciresinol, (+)-kusunokinin, and (+)-methyltrachelogenin, were isolated from MeOH extracts ofW. sikokiana stem. To our knowledge, we have isolated (+)-methyltrachelogenin from plants for the first time. Chiral high-performance liquid chromatographic analysis showed that (+)-kusunokinin and (+)-methyltrachelogenin were optically pure, whereas (–)-lariciresinol and (–)-secoisolariciresinol were not (39% and 45% enantiomer excess, respectively). Feeding experiments with deuterium-labeled substrates demonstrated conversion of coniferyl alcohol to the lignans and interconversion of lignans. These reaction sequences are similar to the sequence catalyzed byForsythia enzymes. However, predominant enantiomers of the lignans, except for secoisolariciresinol isolated fromW. sikokiana, have absolute configurations opposite to those of the corresponding lignans isolated fromForsythia spp. Based on the results of the isolation and the feeding experiments, several differences betweenW. sikokiana andForsythia spp. are pointed out regarding stereochemical mechanisms for lignan biosynthesis.Parts of this report were presented at the 46th annual meeting of the Japan Wood Research Society, Kumamoto, April 1996; and the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997 相似文献
11.
Secoisolariciresinol dehydrogenase activity was detected for the first time from Daphne odora and Daphne genkwa (Thymelaeaceae), which are known to produce optically pure (+)-matairesinol. In sharp contrast, (–)-matairesinol was formed selectively over the (+)-antipode by the secoisolariciresinol dehydrogenase preparation from both D. odora callus and D. genkwa shoots. 相似文献
12.
Nattaya Lourith Takeshi Katayama Kimiko Ishikawa Toshisada Suzuki 《Journal of Wood Science》2005,51(4):379-386
To investigate the biosynthesis and stereochemistry of syringylglycerol-8-O-4′-(sinapyl alcohol) ether (SGSE), a syringyl 8-O-4′ neolignan, feeding experiments and enzyme assays using Eucommia ulmoides were carried out. Diastereoselective formation of erythro-SGSE was found. When [8-14C]sinapyl alcohol was administered to excised shoots of E. ulmoides, 14C was incorporated into free SGSE and SGSE glucosides. In stems, incorporation into (+)-erythro-[14C]SGSE (0.037%) with 9.1% enantiomeric excess (% e.e.) was found; incorporation into the threo isomer was not detectable. Erythro-[14C]SGSE glucosides (0.047%) dominated over threo forms (0.007%) with 74.0% diastereomeric excess (% d.e.); both diastereomers were levorotatory with 32.0% e.e. and 18.3% e.e., respectively. In leaves, higher incorporation into (−)-erythro-[14C]SGSE (0.500%, 15.9% e.e.) than into the threo isomer (0.206%, 7.4% e.e.) was observed (41.6% d.e.). (−)-Erythro-[14C]SGSE glucosides (1.692%, 25.0% e.e.) were produced at higher rates than threo isomers (0.177%, 16.4% e.e.) with 81.0% d.e. In incubations of a mixture of [8-14C]sinapyl and [8-14C]coniferyl alcohols with an insoluble enzyme preparation from stems of E. ulmoides, erythro-SGSE was preferentially produced. The highest % d.e. (82.8) was observed at 60 min with the (+)-erythro isomer (21.4% e.e.) and the (−)-threo form (4.3% e.e.).Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002, and the 47th Lignin Symposium, Fukuoka, October 2002 相似文献
13.
In the passive-avoidance test R-(+)-hyoscyamine (10-100 microg kg(-1) i.p.) prevented amnesia induced by antimuscarinic treatment with AF-64A and benzhexol. The antiamnesic effect of R-(+)-hyoscyamine was comparable to that exerted by the cholinesterase inhibitor physostigmine (0.2 mg kg(-1) i.p) and the M(1) selective agonist AF-102B (10 mg kg(-1) i.p.). In the social learning test, R-(+)-hyoscyamine (10-100 microg kg(-1) i.p.) in adults rats, reduced the duration of active exploration of the familiar partner in the second session of the test similar to the nootropic drug piracetam (30 mg kg(-1) i.p.). These results demonstrated the ability of R-(+)-hyoscyamine to modulate memory functions and suggest that R-(+)-hyoscyamine could be useful in the treatment of cognitive deficits. 相似文献
14.
Methanol extractives from the red heartwood of Bengal catechu (Acacia catechu) contained (+)-catechin as a major component making up 0.3% of the wood. A new polyphenolic compound with a (+)-homo-iso-catechin structure and having catechol and phloroglucinol moieties constituted 0.005% of the wood, and probably its epimeric compound in trace amounts, were also found.This report was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999 and the 44th Lignin Symposium, Gifu, October 1999 相似文献
15.
In the search for new sources of sesquiterpene lactones, six Centaurea species have been analyzed. The activity against the fungus Cunninghamella echinulata of (+)-cnicin (1) and (+)-salonitenolide (2), isolated from the Centaurea plants, as well as that of (+)-costunolide (3), (-)-dehydrocostuslactone (4), (-)-lychnopholide (5) and (-)-eremantholide C (6), has been evaluated. Compounds 3 and 4 showed noticeable EC50 values, whilst more polar lactones were inactive. These results suggest that a relatively low polarity is one of the molecular requirements for the antifungal activity of sesquiterpene lactones. 相似文献
16.
A new isocoumarin, 7-hydroxyl-4-methyl isocoumarine (1), together with three known monoterpenes, (3R, 4R, 6S)-3, 6-dihydroxy-1-menthene (2), (+)-(1R, 3S, 4R, 6S)-6-hydroxymenthol (3) and 4-isopropyl-1-methylcyclohex-2-ene-1, 6-diol (4), was isolated from the methanol extract of Brickellia rosmarinifolia. The structures were determined by spectroscopic means. Compounds 1, 2, 3 and 4 showed antifungal activities against Colletotrichum musae and Peronophythora litchii in vitro. 相似文献
17.
18.
Effects of magnesium deficiency and variation in nitrate to ammonium ratio on needle histology and chlorophyll concentration were investigated in current-year and one-year-old needles of clonal Norway spruce trees (Picea abies (L.) Karst.). Six-year-old trees were grown for one year in sand culture with circulating nutrient solutions containing a sufficient (0.2 mM) or a limiting (0.04 mM) concentration of Mg. The nitrogen concentration was not varied (5 mM), but the NO(3) (-)/NH(4) (+)-ratio was adjusted to 0.76 in Mg-sufficient and to 1.86, 0.76 or 0.035 in Mg-limited plants. Visible symptoms of Mg deficiency occurred only in current-year needles, indicating adequate Mg nutrition before the experiment. Under conditions of Mg limitation, chlorophyll and Mg concentrations were lowest in needles of trees supplied with NH(4) (+) as the major nitrogen source and highest in needles of trees supplied with NO(3) (-) as the major nitrogen source. In current-year and one-year-old needles, starch accumulation induced by Mg deficiency was increased when NH(4) (+) was the major nitrogen source. The accumulation of tannin spherules in current-year needles, which occurred in response to Mg deficiency, also increased with decreasing NO(3) (-)/NH(4) (+)-ratios. Deficient Mg supply caused premature aging in tissues of the vascular bundle, as indicated by modifications of the cambium and increased amounts of collapsed sieve cells. The number of collapsed sieve cells was slightly lower in needles grown in a NH(4) (+)-dominated nutrient regime than in needles grown in a NO(3) (-)-dominated nutrient regime. We conclude that was not directly toxic to Norway spruce trees at the applied concentrations. However, effects of Mg deficiency were considerably greater in an NH(4) (+)-dominated nutrient regime than in a NO(3) (-)-dominated nutrient regime. 相似文献
19.
Bonjar GH 《Fitoterapia》2004,75(2):231-235
Fifty methanolic plant extracts belonging to 44 plant species of 33 families finding use in Iranian folkloric medicine were screened for antibacterial activity. Thirty samples, including 28 species in 20 families, had antibacterial activity against at least on one of the bacteria. Among the active plants, 32.6% were active against G(-), 62% against G(+), and 47.3% against both G(-) and G(+) bacteria. Dianthus coryophyllus was active against all tested G(-) and G(+) bacteria except Micrococcus luteus. Most susceptible G(-) bacteria were Klebsiella pneumoniae and Bordetella bronchiseptica and least susceptible G(-) bacterium was Escherichia coli. In G(+) bacteria, most and least susceptible were Staphylococcus aureus and M. luteus, respectively. The least MIC, as 0.62 mg/ml, belonged to Myrtus communis seeds against S. aureus, Bacillus cereus and B. bronchiseptica, and to Terminalia chebula ripe seeds against S. aureus. 相似文献
20.
We compared the acidity, the external acid neutralizing capacity and the buffering capacity of leaves of four commercially important tree species, largetooth aspen (Populus grandidentata Michx.), sugar maple (Acer saccharum Marsh.), paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill), at two sites of contrasting soil fertility in southern Quebec. External acid neutralizing capacity (ENC) of leaves was determined by measuring the change in pH induced by soaking fresh leaves in an acidic solution (pH 4.0) for two hours. The ENC was highest for largetooth aspen (14.3 micro equiv H(+) g(-1)), and lowest for sugar maple and balsam fir (< 5 micro equiv H(+) g(-1)). The buffering capacity index (BCI) was determined by measuring the amount of acid necessary to produce a change of 5 micro equiv H(+) in the leaf homogenate. The BCI ranged from 883 micro equiv H(+) g(-1) for largetooth aspen to less than 105 micro equiv H(+) g(-1) for sugar maple and balsam fir. Leaves of sugar maple and balsam fir had a lower internal pH and a higher percentage of ENC over BCI than paper birch and largetooth aspen. Overall, ENC was correlated with the concentration of all leaf nutrients except Ca, and BCI was correlated with Mg, N and Ca. The site effect was relatively unimportant for all variables. 相似文献