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Massimo Confalonieri † Maria Cammareri † Elisa Biazzi † Paola Pecchia Manuel Pedro Salema Fevereiro Alma Balestrazzi Aldo Tava Clara Conicella 《Plant biotechnology journal》2009,7(2):172-182
Triterpene saponins are a group of bioactive compounds abundant in the genus Medicago , and have been studied extensively for their biological and pharmacological properties. In this article, we evaluated the effects of the ectopic expression of AsOXA1 cDNA from Aster sedifolius on the production of triterpene saponins in barrel medic ( Medicago truncatula Gaertn.). AsOXA1 cDNA encodes β-amyrin synthase, a key enzyme involved in triterpene saponin biosynthesis. One of the four transgenic lines expressing AsOXA1 accumulated significantly larger amounts of some triterpenic compounds in leaf and root than did control plants. In particular, the leaf exhibited significantly higher levels of bayogenin, medicagenic acid and zanhic acid. The amounts of medicagenic acid and zanhic acid, which represent the core of the M. truncatula leaf saponins, were 1.7 and 2.1 times higher, respectively, than the amounts extracted from the control line. In root, the production of bayogenin, hederagenin, soyasapogenol E and 2β-hydroxyoleanolic acid was increased significantly. The increase in the total amounts of triterpenic compounds observed in the leaves of transgenic lines correlated with the AsOXA1 expression level. Interestingly, the plants expressing AsOXA1 showed, under different growth conditions, improved nodulation when compared with the control line. Nodulation enhancement was also accompanied by a significant change in the soyasapogenol B content. Our results indicate that the ectopic expression of AsOXA1 in barrel medic leads to a greater accumulation of triterpene saponins and enhanced root nodulation. 相似文献
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Iturbe-Ormaetxe I Haralampidis K Papadopoulou K Osbourn AE 《Plant molecular biology》2003,51(5):731-743
Cloning of OSCs required for triterpene synthesis from legume species that are amenable to molecular genetics will provide tools to address the importance of triterpenes and their derivatives during normal plant growth and development and also in interactions with symbionts and pathogens. Here we report the cloning and characterization of a total of three triterpene synthases from the legume species Medicago truncatula and Lotus japonicus. These include a -amyrin synthase from M. truncatula (MtAMYI) and a mixed function triterpene synthase from Lotus japonicus (LjAMY2). A partial cDNA predicted to encode a -amyrin synthase (LjAMY1) was also isolated from L. japonicus. The expression patterns of MtAMY1, LjAMY1 and LjAMY2 and of additional triterpene synthases previously characterised from M. truncatula and pea differ in different plant tissues and during nodulation, suggesting that these enzymes may have distinct roles in plant physiology and development. 相似文献
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S.A. Holanda Pinto L.M.S. Pinto M.A. Guedes G.M.A. Cunha M.H. Chaves F.A. Santos V.S. Rao 《Phytomedicine》2008,15(8):630-634
The effects of α,β-amyrin, a pentacyclic triterpene isolated from Protium heptaphylum was investigated on rat model of orofacial pain induced by formalin or capsaicin. Rats were pretreated with α,β-amyrin (10, 30, and 100 mg/kg, i.p.), morphine (5 mg/kg, s.c.) or vehicle (3% Tween 80), before formalin (20 μl, 1.5%) or capsaicin (20 μl, 1.5 μg) injection into the right vibrissa. In vehicle-treated controls, formalin induced a biphasic nociceptive face-rubbing behavioral response with an early first phase (0–5 min) and a late second phase (10–20 min) appearance, whereas capsaicin produced an immediate face-rubbing (grooming) behavior that was maximal at 10–20 min. Treatment with α,β-amyrin or morphine significantly inhibited the face-rubbing response in both test models. While morphine produced significant antinociception in both phases of formalin test, α,β-amyrin inhibited only the second phase response, more prominently at 30 mg/kg, in a naloxone-sensitive manner. In contrast, α,β-amyrin produced much greater antinociceptive effect at 100 mg/kg in the capsaicin test, which was also naloxone-sensitive. These results provide first time evidence to show that α,β-amyrin attenuates orofacial pain atleast, in part, through a peripheral opioid mechanism but warrants further detailed study for its utility in painful orofacial pathologies. 相似文献
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Dammarenediol-II synthase, the first dedicated enzyme for ginsenoside biosynthesis, in Panax ginseng
Panax ginseng produces triterpene saponins called ginsenosides, which are classified into two groups by the skeleton of aglycones, namely dammarane type and oleanane type. Dammarane-type ginsenosides dominate over oleanane type not only in amount but also in structural varieties. However, their sapogenin structure is restricted to two aglycones, protopanaxadiol and protopanaxatriol. So far, the genes encoding oxidosqualene cyclase (OSC) responsible for formation of dammarane skeleton have not been cloned, although OSC yielding oleanane skeleton (β-amyrin synthase) has been successfully cloned from this plant. In this study, cDNA cloning of OSC producing dammmarane triterpene was attempted from hairy root cultures of P. ginseng by homology based PCR method. A new OSC gene (named as PNA) obtained was expressed in a lanosterol synthase deficient (erg7) Saccharomyces cerevisiae strain GIL77. LC-MS and NMR analyses identified the accumulated product in the yeast transformant to be dammarenediol-II, demonstrating PNA to encode dammarenediol-II synthase. 相似文献
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Catello Pane Domenica Villecco Graziana Roscigno Enrica De Falco Massimo Zaccardelli 《Archives Of Phytopathology And Plant Protection》2013,46(13):1533-1539
The effect of plant essential oils, Solanum chilense and Aster sedifolius raw saponins, plant-derived colourants and Brassica carinata glucosinolate-containing tissues, for the control of seedborne fungi Alternaria dauci, Alternaria radicina, Colletotrichum lindemuthianum and Ascochyta rabiei, was evaluated. In vitro assays indicated that oregano essential oil, bark chestnut-derived colourant and B. carinata meals, showed a large spectrum of activity against all pathogens. S. chilense raw saponins were effective against A. dauci and A. radicina, while those from A. sedifolius also inhibited significantly C. lindemuthianum. Screening showed the antifungal potential of natural compounds. 相似文献
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Marta Lipinski Martin Scholz Kay Pieper Rainer Fischer Dirk Prüfer Kai J. Müller 《Central European Journal of Biology》2009,4(2):163-169
Squalene epoxidase catalyzes the formation of 2,3-oxidosqualene from squalene and in plants is the last enzyme common to all
biosynthetic pathways leading to an array of triterpene derivatives like phytosterols, brassinosteroid phytohormones or saponins.
In this work, we present a squalene epoxidase gene (NSSQE1) from the triterpene saponin producing plant Nigella sativa. The gene product showed a high degree of homology to functional squalene epoxidases (SQEs) from Arabidopsis thaliana and was able to complement SQE deficient yeast that harboured a knockout mutation in the underlying erg1 gene. Moreover, the expression of the NSSQE1 gene in ERG1 wild type yeast revealed that NSSQE1 conferred resistance towards terbinafine, an inhibitor of fungal SQEs. The latter suggested
that a terbinafine-dependent NSSQE1 selection marker system can be developed for yeast. The gene NSSQE1 was ubiquitously expressed in all plant tissues analysed, including roots where no triterpene saponins are produced. Therefore,
we argue that NSSQE1 is a housekeeping gene for triterpene metabolism in Nigella sativa. Similar to triterpene saponins, NSSQE1 was up-regulated by methyl jasmonate in leaves and should also be functionally involved in saponin biosynthesis in Nigella sativa. 相似文献
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Rishi K. Vishwakarma Prashant Sonawane Somesh Singh Uma Kumari Ruby Bashir M. Khan 《Physiology and Molecular Biology of Plants》2013,19(4):547-553
Triterpenoid saponins are the class of secondary metabolites, synthesized via isoprenoid pathway. Oxidosqualene cyclases (OSCs) catalyzes the cyclization of 2, 3-oxidosqualene to various triterpene skeletons, the first committed step in triterpenoid biosynthesis. A full-length oxidosqualene cyclase cDNA from Bacopa monniera (BmOSC) was isolated and characterized. The open reading frame (ORF) of BmOSC consists of 2,292 bp, encoding 764 amino acid residues with an apparent molecular mass of 87.62 kDa and theoretical pI 6.21. It contained four QxxxxxW motifs, one Asp-Cys-Thr-Ala-Glu (DCTAE) motif which is highly conserved among the triterpene synthases and another MWCYCR motif involved in the formation of triterpenoid skeletons. The deduced amino acid sequence of BmOSC shares 80.5 % & 71.8 % identity and 89.7 % & 83.5 % similarity with Olea europaea mixed amyrin synthase and Panax notoginseng dammarenediol synthase respectively. Phylogenetic analysis revealed that BmOSC is closely related with other plant OSCs. Quantitative real-time PCR (qRT-PCR) data showed that BmOSC is expressed in all tissues examined with higher expression in stem and leaves as compared to roots and floral parts. 相似文献
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The root of Bupleurum falcatum L. (Apiaceae) has long been one of the most important traditional herbal medicines in Asian countries. A group of triterpene
saponins (saikosaponins) are the major constituents of this plant. Squalene synthase (SS) may play a regulatory role in directing
triterpene intermediates and sterol pathways. Here, we investigated the regulatory role of the squalene synthase (BfSS1) gene in the biosynthesis of phytosterol and triterpene in B. falcatum. BfSS1 mRNA accumulated ubiquitously in plant organs and markedly increased in roots after treatment with methyl jasmonate (MeJA),
ABA and ethephon. Transgenic B. falcatum constructs overexpressing BfSS1 in the sense and antisense orientations were assembled using the Agrobacterium-mediated method. Transgenic roots overexpressing BfSS1 in the sense orientation resulted in enhanced production of both phytosterol and saikosaponins. Overexpression of the BfSS1 gene in the sense orientation increased the mRNA accumulation of downstream genes such as squalene epoxidase and cycloartenol
synthase but unexpectedly decreased the mRNA levels of β-amyrin synthase (β-AS), a triterpene synthase mRNA. MeJA treatment
of wild-type roots strongly stimulated β-AS mRNA accumulation and saikosaponin production but suppressed phytosterol production.
MeJA treatment of transgenic roots overexpressing BfSS1 in the sense orientation failed to stimulate β-AS mRNA accumulation but still enhanced saikosaponin and phytosterol production.
These results indicate that overexpression of BfSS1 in B. falcatum regulates more powerfully the downstream genes than elicitor (MeJA) treatment in triterpene and phytosterol biosynthesis. 相似文献
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Uraline, a new norditerpenoid alkaloid, was isolated from aerial parts of Delphinium uralense. The structure of 1α,7,8-trihydroxy-6β,14α,16β-trimethoxy-18-N-(2-methyl)succinylanthranoyloxyaconane was ascribed to the new compound on the basis of 1H and 13C NMR, IR, and mass spectra. The known alkaloids methyllycaconitine and delcorine were also isolated from the plant.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 4, 2005, pp. 425–429.Original Russian Text Copyright © 2005 by Gabbasov, Tsyrlina, Spirikhin, Danilov, Yunusov. 相似文献
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Chenopodium quinoa Willd. is a valuable food source which has gained importance in many countries of the world. The plant contains various bitter-tasting
saponins which present an important antinutritional factor. Various triterpene saponins have been reported in C. quinoa including both monodesmosidic and bidesmosidic triterpene saponins of oleanolic acid, hederagenin, phytolaccagenic acid,
and serjanic acid as the major aglycones and other aglycones as 3β-hydroxy-23-oxo-olean-12-en-28-oic acid, 3β-hydroxy-27-oxo-olean-12-en-28-oic
acid, and 3β, 23α, 30β-trihydroxy-olean-12-en-28-oic acid. A tridesmosidic saponin of hederagenin has also been reported.
Here we review the occurrence, analysis, chemical structures, and biological activity of triterpene saponins of C. quinoa. In particular, the mode of action of the mono- and bidesmosidic triterpene saponins and aglycones are discussed. 相似文献
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Soybean seeds contain substantial amount of diverse triterpenoid saponins that influence the seed quality, although little
is known about the physiologic functions of saponins in plants. We now describe the modification of saponin biosynthesis by
RNA interference (RNAi)-mediated gene silencing targeted to β-amyrin synthase, a key enzyme in the synthesis of a common aglycon
of soybean saponins. We identified two putative β-amyrin synthase genes in soybean that manifested distinct expression patterns
with regard to developmental stage and tissue specificity. Given that one of these genes, GmBAS1, was expressed at a much higher level than the other (GmBAS2) in various tissues including the developing seeds, we constructed two RNAi vectors that encode self-complementary hairpin
RNAs corresponding to the distinct regions of GmBAS1 under the control of a seed-specific promoter derived from the soybean gene for the α′ subunit of the seed storage protein
β-conglycinin. These vectors were introduced independently into soybean. Six independent transgenic lines exhibited a stable
reduction in seed saponin content, with the extent of saponin deficiency correlating with the β-amyrin synthase mRNA depletion.
Although some transgenic lines produced seeds almost devoid of saponins, no abnormality in their growth was apparent and the
antioxidant activity of their seeds was similar to that of control seeds. These results suggest that saponins are not required
for seed development and survival, and that soybean seeds may therefore be amenable to the modification of triterpenoid saponin
content and composition through molecular biologic approaches. 相似文献
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Two iridoid glucosides, 8-epi-grandifloric acid and 3′-O-β-glucopyranosyl-stilbericoside, were isolated from the aerial part of Thunbergia laurifolia along with seven known compounds, benzyl β-glucopyranoside, benzyl β-(2′-O-β-glucopyranosyl) glucopyranoside, grandifloric acid, (E)-2-hexenyl β-glucopyranoside, hexanol β-glucopyranoside, 6-C-glucopyranosylapigenin and 6,8-di-C-glucopyranosylapigenin. Strucural elucidation was based on the analyses of spectroscopic data. 相似文献
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Three main saponins were isolated from the seeds of Albizzia lucida. Their structures were established by spectral analyses and chemical and enzymatic transformations as 3-O-[β-
-xylopyranosyl(1→2)-α-
-arabinopyranosyl (1→6)] [β-
-glucopyranosyl (1→2)] β-
-glucopyranosyl echinocystic acid; 3-O-[α-
-arabinopyranosyl (1→6)][β-
-glucopyranosyl (1→2)]-β-
-glucopyranosyl echinocystic acid and 3-O-[β-
-xylopyranosyl (1→2)-β-
-fucopyranosyl (1→6)-2-acetamido-2-deoxy-β-
-glucopyranosyl echinocystic acid, characterized as its methyl ester. 相似文献