Angelika Otto

Chemosystematics and diagenesis of terpenoids in fossil conifer species and sediment from the Eocene Zeitz formation, Saxony, Germany

The biomarker contents of three fossil conifer species (Athrotaxis couttsiae, Taxodium balticum, Pinus palaeostrobus) and the clay sediment from the Eocene Zeitz formation, Germany, have been analyzed by gas chromatography-mass spectrometry. Triterpenoids of the oleanane, ursane and lupane series and aliphatic wax lipids are the major compounds in the total extracts of the sediment indicating a major angiosperm input. In contrast, diterpenoids (abietanes, phenolic abietanes, pimaranes, isopimaranes, kauranes, phyllocladanes, totaranes) and lignin degradation products are predominant in the conifer fossil extracts. Polar diterpenoids (ferruginol and derivatives, dehydroabietic acid) are preserved as major compounds in the conifers, accompained by saturated and aromatic diterpenoid products. The extracts of the fossil conifer species show characteristic biomarker patterns and contain terpenoids of chemosystematic value. The terpenoid composition of the fossil conifers is similar to that of related modern species. Phenolic abietanes (ferruginol, 6,7-dehydroferruginol, hydroxyferruginols, sugiol) which are known from modern species of the Cupressaceae and Podocarpaceae are the major terpenoids in shoots of Athrotaxis couttsiae and a cone of Taxodium balticum (both Cupressaceae). Sesquiterpenoids characteristic for Cupressaceae (cuparene, α-cedrene) are also present in Athrotaxis. Abietane-type acids (dehydroabietic acid, abietic acid) and saturated abietanes [fichtelite, 13α(H)-fichtelite] predominate in the extracts of a Pinus palaeostrobus cone and phenolic abietanes are not detectable. A diagenetic pathway for the degradation of abietic acid is proposed based on the presence of abietane-type acids and a series of their presumed degradation products in the Pinus cone. The formation of diagenetic products from the phenolic abietanes is also discussed.

Terpenoid composition of three fossil resins from Cretaceous and Tertiary conifers

The terpenoid composition of three fossil resins from macrofossils of Cretaceous and Tertiary conifers has been analyzed by gas chromatography–mass spectrometry (GC–MS). The mono-, sesqui- and diterpenoids which have been identified in the resin extracts are derived from precursors produced by the respective source plants and may be used as chemosystematic markers when compared with terpenoids in extant conifers. Sesquiterpenoids (cedrene, cuparene, cadinanes) and phenolic diterpenoids (ferruginol and derivatives) are the major components in Cupressospermum saxonicum Mai (Miocene). The terpenoid characteristics strongly support a relationship to the Cupressaceae s. str. The resin of Doliostrobus taxiformis (Sternberg) Kvacek (Eocene) consists of abietane and pimarane type resin acids accompanied by minor amounts of phenolic diterpenoids (ferruginol, hinokiol). According to morphological and anatomical characteristics, D. taxiformis was previously compared to both, extant Araucariaceae and Cupressaceae s.l., but the terpenoid pattern of the resin now supports a relationship to the Cupressaceae s.l. rather than to Araucariaceae. Degraded diterpenoids of the abietane type are the major compounds in the extract of Tritaenia linkii (Roemer) Magdefrau et Rudolf (Lower Cretaceous) indicating considerable oxidative alteration of the resin. Since the terpenoids in the resin of T. linkii are highly degraded or belong to the common abietane class, the leaves cannot be assigned or compared to any modern family based on their terpenoid composition. The presence of ferruginol probably excludes pinaceous affinities. Terpenoids proved to be valuable chemosystematic markers for fossil conifers once they are adequately preserved. The analysis of resin extracts by GC–MS is a suitable tool for the investigation of soluble compounds in fossil plants.

Resin compounds from the seed cones of three fossil conifer species from the Miocene Clarkia flora, Emerald Creek, Idaho, USA, and from related extant species

Abstract The terpenoid compositions of three conifer species from the Miocene Clarkia flora, Emerald Creek, Idaho, USA, and of related extant species were analyzed using gas chromatography-mass spectrometry. The extracts of the seed cones of Miocene Taxodium dubium , Glyptostrobus oregonensis , and Cunninghamia chaneyi (Cupressaceae s.l.) contain several sesqui- and diterpenoids which originate from the resins. Many of the terpenoids have been degraded to their diagenetic products (geoterpenoids), but some compounds are preserved unaltered as the natural products (bioterpenoids). The fossil conifer species show characteristic diterpenoid patterns which in part match the compounds that have been found in the extant species. Fossil and extant species contain terpenoids characteristic for the Cupressaceae. Abietane type diterpenoids are the major compounds in the fossil T. dubium and the extant Taxodium distichum . G. oregonensis contains abietane and labdane derivatives as observed in the extant Glyptostrobus pensilis . Monoterpenoids and predominant diterpenoid acids and alcohols of the abietane and pimarane type characterize C. chaneyi and the extant Cunninghamia lanceolata . Based on the occurrence of unaltered bioterpenoids and their presumed degradation products in the fossil conifers, diagenetic pathways of some abietane, pimarane and ispopimarane type diterpenoids are proposed. The results show that terpenoids are valuable molecular markers for (paleo)systematics and phylogeny of conifers.

Polar aromatic biomarkers in the Miocene Maritza-East lignite, Bulgaria

Aromatic and polar compounds of lignite lithotype bitumens (Maritza-East) were analyzed. Diterpenoid phenols and ketophenols, i.e., mainly ferruginol, sugiol, hinokione, and products of their diagenetic transformations, were identified as the dominant biomarkers. A variety of sesquiterpenoids was present as well. These compounds provided evidence for the assumption that members of the Cupressaceae s. 1. are the coal precursors. Polar triterpenoids, i.e., lupeol, lupenone, adiantone and hopanones were present in subordinate quantities in the humoclarain sample. These biomarkers support an input of deciduous (angiosperm) vegetation to the peat swamp source matter. Three diagenetic transformation schemes for the diterpenoid phenols/ketophenols are proposed: (1) ferruginol and/or sugiol alteration through dehydrogenation, demethylation and ring-B-cleavage; (2) hinokione aromatization to simonellite; and (3) 7-ketototarol change through 7-ketototar-5-enol to 20-nor-3-oxo-totara-5(10),6-dienol. The identified diterpenoids demonstrated the presence of Gymnospermae in the coal forming community. Furthermore, the phenolic diterpenoids indicated a specific input of organic matter from conifers of the Cupressaceae/Taxodiaceae or Podocarpaceae as the most abundant trees in the coal forming swamp.

Biomarkers of Holocene buried conifer logs from Bella Coola and north Vancouver, British Columbia, Canada

Abstract The biomarker compositions of a Holocene seep oil (liquefied resin) originating from a buried log of Douglas fir (Pseudotsuga menziesii) from Bella Coola, BC, Canada, and a Holocene pine wood (Pinus sp.) sample from north Vancouver, BC, Canada, were analyzed using gas chromatography–mass spectrometry (GC–MS). The total extract of the Bella Coola sample contains the sesquiterpenoid derivative calamenene and diterpenoids of the labdane, abietane, pimarane, and phyllocladane classes. A novel series of successively degraded labdane derivatives (labdan-15-oic acid, norlabdanoic acids, drimenoic acid) was detected in the polar fraction and a diagenetic pathway is proposed. Aromatic abietanes are the major components in the neutral fraction. The neutral fraction of the pine wood contains two sesquiterpenoids (calamenene, cadalene), diterpenoids of the abietane, pimarane, isopimarane, and kaurane classes, and a series of steroids. 18-Norabieta-8,11,13-triene (dehydroabietin) is the major component among the predominantly aromatic abietanes. Based on the compositions of the terpenoids it is concluded that the diagenesis of the pine and Douglas fir logs probably occurred under anaerobic conditions leading to reductive reactions such as decarboxylation of resin acids, with concurrent oxidation reactions to form the aromatic derivatives.

Biomolecules preserved in ca. 168 million year old fossil conifer wood

Biomarkers are widely known to occur in the fossil record, but the unaltered biomolecules are rarely reported from sediments older than Paleogene. Polar terpenoids, the natural products most resistant to degradation processes, were reported mainly from the Tertiary conifers, and the oldest known are Cretaceous in age. In this paper, we report the occurrence of relatively high concentrations of ferruginol derivatives and other polar diterpenoids, as well as their diagenetic products, in a conifer wood Protopodocarpoxylon from the Middle Jurassic of Poland. Thus, the natural product terpenoids reported in this paper are definitely the oldest polar biomolecules detected in geological samples. The extracted phenolic abietanes like ferruginol and its derivatives (6,7-dehydroferruginol, sugiol, 11,14-dioxopisiferic acid) are produced only by distinct conifer families (Cupressaceae s. l., Podocarpaceae and Araucariaceae), to which Protopodocarpoxylon could belong based on anatomical characteristics. Therefore, the natural product terpenoids are of great advantage in systematics of fossil plant remains older than Paleogene and lacking suitable anatomical preservation.

Novel phenolic biomarker triterpenoids of fossil laticifers in Eocene brown coal from Geiseltal, Germany

Abstract Novel phenolic triterpenoids were tentatively identified with known mono-, tri- and tetraaromatic oleanane, ursane, and lupane hydrocarbons and natural product precursors (α-amyrone, α-amyrin) in the extract of Eocene fossil laticifers called “Affenhaar” from the Geiseltal lignites, Germany. The novel phenolic terpenoids are mono- and triaromatic hydroxytriterpenoids (OH at position 1, 2 or 3) of the oleanane, ursane, and lupane classes: hydroxy-24,25-dinoroleana-1,3,5(10),12-tetraene, hydroxy-24,25-dinorlupa-1,3,5(10)-triene, hydroxy-24,25-dinorlupa-1,3,5(10),19(22)-tetraene, hydroxy-24,25,26,27-tetranorursa-1,3,5,7,9,11,13-heptaene, hydroxy-24,25,26,27-tetranoroleana-1,3,5,7,9,11,13-heptaene, and hydroxy-24,25,26,27-tetranorlupa-1,3,5,7,9,11,13-heptaene. The structures of the novel compounds were proposed based on the interpretation of the gas chromatography–mass spectrometry data of the underivatized and silylated total extract.