- Pinoresinol-lariciresinol reductase: Substrate versatility, enantiospecificity, and kinetic properties
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Two western red cedar pinoresinol-lariciresinol reductase (PLR) homologues were studied to determine their enantioselective, substrate versatility, and kinetic properties. PLRs are downstream of dirigent protein engendered, coniferyl alcohol derived, stereoselective coupling to afford entry into the 8- and 8′-linked furofuran lignan, pinoresinol. Our investigations showed that each PLR homolog can enantiospecifically metabolize different furofuran lignans with modified aromatic ring substituents, but where phenolic groups at both C4/C4′ are essential for catalysis. These results are consistent with quinone methide intermediate formation in the PLR active site. Site-directed mutagenesis and kinetic measurements provided additional insight into factors affecting enantioselectivity and kinetic properties. From these data, PLRs can be envisaged to allow for the biotechnological potential of generation of various lignan skeleta, that could be differentially “decorated” on their aromatic ring substituents, via the action of upstream dirigent proteins.
- Davin, Laurence B.,Hwang, Julianne K.,Lewis, Norman G.,Moinuddin, Syed G. A.
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- Effect of the benzylic structure of lignan on antioxidant activity
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The effect of the benzylic structure of lignan on antioxidant activity was evaluated. Secoisolariciresinol (1) and 3,4-bis(4-hydroxy-3-methoxybenzyl) tetrahydrofuran (2), which have two secondary benzylic positions without oxygen, showed the highest antioxidant activity. Optically active verrucosin (4) was synthesized for the first time in this experiment.
- Yamauchi, Satoshi,Sugahara, Takuya,Matsugi, Junko,Someya, Tatsushi,Masuda, Toshiya,Kishida, Taro,Akiyama, Koichi,Maruyama, Masafumi
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p. 2283 - 2290
(2008/03/17)
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- Synthetic transformation of hydroxymatairesinol from Norway spruce (picea abies) to 7-hydroxysecoisolariciresinol, (+)-lariciresinol and (+)-cyclolariciresinol
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We have developed a method for the transformation of hydroxymatairesinol to optically pure (+)-lariciresinol and (+)-cyclolariciresinol via the hitherto unreported lignan 7-hydroxysecoisolariciresinol. The two naturally occurring isomers of hydroxymatairesinol were reduced with LiAlH4 to a mixture of two epimers of 7-hydroxysecoisolariciresinol, which were further selectively transformed to (+)-lariciresinol and (+)-cyclolariciresinol by an acid catalysed intramolecular cyclisation reaction. The structure of the major isomer of 7-hydroxysecoisolariciresinol was confirmed by X-ray crystallography and thereby also the absolute configurations of the two isomers of hydroxymatairesinol were unambiguously proven. Optical purities were determined by chiral HPLC-MS/MS and optical rotation measurements.
- Eklund, Patrik,Sillanpaeae, Reijo,Sjoeholm, Rainer
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p. 1906 - 1910
(2007/10/03)
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- Furanoid and furofuranoid lignans from Daphne oleoides
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Furofuranoid lignan (1) and (2) and furanoid lignan (3) have been isolated from Daphne oleoides and their structures elucidated through chemical and spectroscopic studies as 2-(3′-methoxy-4′-O-α-D-galactopyranosylphenyl)-6-(3″- methoxy-4″-hydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane (1), 2-(3′,5′-dimethoxy-4′-O-α-D-galactopyranosylphenyl)-6- (3″-methoxy-4″-hydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane (2), and 4,9′-dihydroxy-3,3′-dimethoxy-4′-O-ss-D-glucopyranosyl- 7′,9-epoxylignan (3). Two known lignans (4) and (5) have also been reported for the first time from this species.
- Riaz, Muhammad,Ullah, Nisar,Mehmood, Arshad,Nawaz, Hafiz Rab,Malik, Abdul,Afza, Nighat
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p. 1216 - 1220
(2007/10/03)
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- Lignan bis-glucosides from Galium sinaicum
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The new lariciresinol-based lignan bis-glucosides, 7S, 8R, 8'R-(-)- Iariciresinol-4,4'-bis-O-β-D-glucopyranoside and 7S, 8R, 8'R-(-)-5- methoxylariciresinol-4,4'-bis-O-β-D-glucopyranoside, together with (-)- syringaresinol-4,4'-bis-O-β-D-glucopyranoside were isolated from the n- butanol extract of Galium sinaicum roots and their structures were established by various spectroscopic techniques. The isolated compounds represent the first report of lignan glycosides from the Rubiaceae. The two lariciresinol-type glucosides exhibited weak cytotoxic activity against the P388 cell line.
- El Gamal,Takeya,Itokawa,Halim,Amer,Saad
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p. 597 - 600
(2007/10/03)
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- Studies on the constituents of Clematis species. VI. The constituents of Clematis stans SIEB et ZUCC
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From the roots of Clematis stans three new oleanane-type triterpenoid saponins named clemastanoside A, B and C, and two new lignan glycosides named clemastanin A and B, have been isolated together with three known triterpenoid saponins, huzhangoside B, C and D, and three known lignan glycosides, (+)-lariciresinol 4-O-β-D-glucopyranoside, (+)-lariciresinol 4'- O-β-D-glucopyranoside and (+)-pinoresinol 4,4'-O-bis-β-D-glucopyranoside. In addition, from the leaves, four new oleanane-type triterpenoid saponins, named clemastanoside D, E, F and G, have been isolated together with five known triterpenoid saponins, hederasaponin B, kizutasaponin K12, huzhangoside B, sieboldianoside B and huzhangoside D, and three known flavonoids, isoquercitrin, ratin and quercetin 3-O-β-D-glucuronopyranoside. The structures of the new compounds were elucidated based on chemical and physicochemical evidence as follows: clemastanoside A, 3-O-β-D- ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl oleanolic acid 28-O-(4-O-acetyl)-α-L-rhamnopyranosyl-(1→4)-β-D- glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (terminal rhamnosyl 4-O- acetate of huzhangoside B); clemastanoside B and C, 3-O-β-D-xylopyranosyl- and 3-O-β-D-ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-β-D- galactopyranosyl oleanolic acid 28-O-α-L-rhamnopyranosyl-(1→4)-β-D- glucopyranosyl-(1→6)-β-D-glucopyranosyl ester, respectively; clemastanoside D, 3-O-β-D-ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L- arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester; clemastanoside E, F and G, terminal rhamnosyl 4-O-, 3-O- and 2-O-acetate of 3-O-β-D- ribopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamno-pyranosyl-(1→4)-β-D-glucopyranosyl-(1→6]-β- D-glucopyranosyl ester, respectively; clemastanin A, (7S,8R)-3-methoxy- 3',4,9,9'-tetrahydroxy-4',7-epoxy-5',8-lignan 3'-O-β-D-glucopyranoside; clemastanin B, (+)-lariciresinol 4,4'-O-bis-β-D-glucopyranoside.
- Kizu,Shimana,Tomimori
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p. 2187 - 2194
(2007/10/03)
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- CHARACTERIZATION OF LARICIRESINOL GLUCOSIDES FROM OSMANTHUS ASIATICUS
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Two lariciresinol glucosides, lariciresinol-4'-O-β-D-glucoside (1) and lariciresinol-4-O-β-D-glucoside (2), were isolated from the bark of Osmanthus asiaticus and the 1H- and 13C-nmr assignments were made by using nOe and 2D-nmr techniques.
- Sugiyama, Masataka,Kikuchi, Masao
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p. 117 - 121
(2007/10/02)
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- LIGNANS OF THE BARK OF Syringa volgaris
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Two lignans have been isolated from the bark of Syringa vulgaris and identified: (+)-lariciresinol 4-β-D-glucopyranoside (I) and -olivil 4-β-D-glucopyranoside (II).This is the first time that glycoside (9) has been described.
- Kurkin, V. A.,Grinenko, N. A.,Zapesochnaya, G. G.
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p. 678 - 680
(2007/10/02)
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- LIGNAN GLYCOSIDES FROM PARSONSIA LAEVIGATA
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Bis-O-rhamnosides of lariciresinol, 5,5'-dimethoxylariciresinol, and secoisolariciresinol, and pinoresinolapiosyl(1->2)-glucoside were isolated from Parsonsia laevigata.Key Word Index - Parsonsia laevigata; Apocynaceae; lariciresinol; lignan rhamnoside; pinoresinol-apiosylglucoside.
- Abe, Fumiko,Yamauchi, Tatsuo
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p. 1737 - 1742
(2007/10/02)
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