Fern constituent: Preoleanatetraene, a novel bicyclic triterpenoid hydrocarbon from Polypodiodes formosana

Arai, Yôko; Hirohara, Masayoshi; Ogawa, Rie; Masuda, Kazuo; Shiojima, Kenji; Ageta, Hiroyuki; Chang, Hsien-Chang; Chen, Yuh-Pan

doi:10.1016/0040-4039(96)00856-8

Cited by 12 publications

(9 citation statements)

References 7 publications

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“…[2][3][4] Since this new enzyme of sterol backbone synthesis has been identified, the known diversity of phytosterols has increased even more. Triterpenoids are plant-characteristic isoprenoids; they also form a large, structurally diverse group of natural products [5][6][7] with more than 100 different carbon skeletons. 8) Some have a variety of pharmacological activities.…”

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confidence: 99%

Chemical Phenotypes of the hmg1 and hmg2 Mutants of Arabidopsis Demonstrate the In-planta Role of HMG-CoA Reductase in Triterpene Biosynthesis

et al. 2007

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Plants produce a wide variety of cyclic triterpenes, such as sterols and triterpenoids, which are the major products of the mevalonate (MVA) pathway. It is important to understand the physiological functions of HMGCoA reductase (HMGR) because HMGR is the rate-limiting enzyme in the MVA pathway. We have previously isolated Arabidopsis mutants in HMG1 and HMG2. Although the biochemical function of HMGR2 has been thought to be almost equal to that of HMGR1, based on similarities in their sequences, the phenotypes of mutants in these genes are quite different. Whereas hmg2 shows no abnormal phenotype under normal growth conditions, hmg1 shows pleiotropic phenotypes, including dwarfing, early senescence, and male sterility. We previously postulated that the 50% decrease in the sterol content of hmg1, as compared to that in the wild type, was a cause of these phenotypes, 1) but comprehensive triterpene profiles of these mutants had not yet been determined. Here, we present the triterpene profiles of hmg1 and hmg2. In contrast to hmg1, hmg2 showed a sterol content 15% lower than that of the wild type. A precise triterpenoid quantification using synthesized deuterated compounds of b b-amyrin (1), a a-amyrin (2), and lupeol (3) showed that the levels of triterpenoids in hmg1 and hmg2 were 65% and 25% lower than in the wild type (WT), respectively. These results demonstrate that HMGR2 as well as HMGR1 is responsible for the biosynthesis of triterpenes in spite of the lack of visible phenotypes in hmg2.

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Chemical Phenotypes of the hmg1 and hmg2 Mutants of Arabidopsis Demonstrate the In-planta Role of HMG-CoA Reductase in Triterpene Biosynthesis

et al. 2007

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“…The other remaining reports of oleanoid tri terpenoids are from ferns, although the most common triterpenoid types in ferns are from the hopane pathway (Pant and Rastogi 1979;Das and Mahato 1983;Baas 1985;Hostett mann and Marston 1995). Oleanoid triterpanoids are reported from Marsilea (oleanane) and Diplazium (ursane; Das and Mahato 1983), and a wide range of triterpanoids, including oleananes, taraxeranes and friedelanes, are present in several species of Polypodium (but not all species; Das and Mahato 1983;Ageta and Arai 1983), Polypodioides (Arai et al 1996), and Lemmaphyllum (Masuda et al 1983). Be cause these are the only reports among the hundreds of fern species examined, these compounds are considered rare among the ferns (Kazuo Masuda personal communica tion 2002).…”

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confidence: 99%

“…Be cause these are the only reports among the hundreds of fern species examined, these compounds are considered rare among the ferns (Kazuo Masuda personal communica tion 2002). In addition, it has been suggested that the oleanane in ferns is formed from a biochemical pathway separate from that found in angiosperms (Arai et al 1996), and the earlier biosynthetic stages might be less likely to produce diagenetic oleanane. Finally, these reports are from genera placed in two relatively phylogenetically derived clades of leptosporangiate ferns with fossil records be ginning during the Mesozoic (Stewart and Rothwell 1993;Pryer et al 2001Pryer et al , 2004Schnei der et al 2004).…”

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confidence: 99%

Biogeochemical evidence for the presence of the angiosperm molecular fossil oleanane in Paleozoic and Mesozoic non-angiospermous fossils

Taylor¹,

Li²,

Dahl³

et al. 2006

Paleobiology

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Recent molecular phylogenetic and molecular clock data both suggest a pre-Mesozoic age for the divergence of the angiosperm lineage from other seed plants, greatly predating the confirmed fossil record of the angiosperm crown group. In addition, molecular phylogenetic stud ies have not supported the morphologically based conclusion that gnetophytes are the extant sister group to angiosperms. We examine these relationships and divergence ages by using a novel ap proach of examining the presence of oleanane. This includes the development of methods using zeolites to preferentially reduce hopanes that can co-elute with oleanane. The presence of this mo lecular fossil strongly correlates with angiosperm diversification; in its functionalized form, along with its triterpenoid precursors, it is found in many living angiosperms. Our data show that among non-angiosperm seed plants examined thus far, oleanane is found only in fossil Cretaceous Bennettitales and Permian Gigantopteridales, both of which share characteristics with angiosperms. Previous morphological phylogenetic results indicate Bennettitales could be a sister group to or member of the angiosperm stem lineage, and results of our preliminary phylogenetic analysis in cluding the Gigantopteridales suggests the same. Our data, based on a new pyrolysis method to treat living species, support previous research indicating that oleanane and its precursors are ab sent in living gnetophytes. If oleanane originated once in seed plants then the angiosperm stem lineage would have diverged from other seed plant lineages by the late Paleozoic.

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“…It possesses a tricyclic skeleton which could be encompass in a group of triterpenes which could be described as irregular. Other examples of these irregular triterpenes are achilleol A ( 2 ), camelliols C and A ( 3 and 4 ), preoleanatetraene ( 5 ), seco -oleananes 6 and 7 , and seco -amyrins 8 and 9 (Figure ) . All are structurally characterized by possessing less rings than those usually found in the oxidosqualene (OS) cyclizations catalyzed by OS cyclases.…”

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First Total Synthesis of (−)-Achilleol B: Reassignment of Its Relative Stereochemistry

et al. 2008

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The first total synthesis of (−)-achilleol B was achieved using a convergent approach with a longest linear sequence of 14 steps. Three key steps were employed, including an enantioselective Robinson annelation for the construction of the bicyclic moiety. The monocyclic synthon was prepared through a Ti(III)-mediated cylization of a chiral monoepoxide obtained via asymmetric dihydroxylation of geranylacetone. The asymmetric preparation of these subunits also permitted us to achieve the enantioselective synthesis of elegansidiol, achilleol A, and farnesiferol B.

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Fern constituent: Preoleanatetraene, a novel bicyclic triterpenoid hydrocarbon from Polypodiodes formosana

Cited by 12 publications

References 7 publications

Chemical Phenotypes of the hmg1 and hmg2 Mutants of Arabidopsis Demonstrate the In-planta Role of HMG-CoA Reductase in Triterpene Biosynthesis

Chemical Phenotypes of the hmg1 and hmg2 Mutants of Arabidopsis Demonstrate the In-planta Role of HMG-CoA Reductase in Triterpene Biosynthesis

Biogeochemical evidence for the presence of the angiosperm molecular fossil oleanane in Paleozoic and Mesozoic non-angiospermous fossils

First Total Synthesis of (−)-Achilleol B: Reassignment of Its Relative Stereochemistry

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