Terpenoids biomarkers

In the mid-1980s, a great deal of emphasis was placed on the discovery of new and useful sterane and terpenoid biomarkers in crude oils and source rocks, and the majority of compounds discovered were in the carbon number range below C35 (Peters Moldowan 1993). There were a couple of exceptions, including hopanes... 

Py-FIMS results clearly reveal the existence of a thermally extractable, bitumen-like fraction which is chemically distinct from the remaining coal components. In lignite, several biomarker compounds were noticeable in the mobile phase components while bituminous coals contain various alkylsubstituted aromatic compounds in the mobile phase. Blind Canyon coal, which contains 11% resinite, exhibits mobile phase components believed to originate from terpenoid aromatization. Curie-point Py-LVMS results illustrate the importance of the oxidation status of coal for studying the mobile phase since mild air oxidation severely changes the structural characteristics of the thermally extractable mobile phase. 

Many natural products, i.e. homologous aliphatic (lipids), polar (sugars, amino acids), and cyclic (terpenoids) compounds can be utilized as biomarkers. The following is a brief overview of the classical biomarkers commonly used, namely lipids and terpenoids. 

XIV, R = CH3 and C2H5, respectively, Fig. 10b), whereas the sediment contains additional friedelin, i-friedelanol and ursolic acid. Furthermore, the friedelin photoproducts, i.e. dihydroputranjivic acid (3,4-r c<7-friedelan-3-oic acid, XV) and 4a- and 4P-3-norfriedelane (XVI) are dominant sedimentary components. Thus, characterizing photoproducts from terpenoids may provide additional biomarker tracer compounds for environmental studies. 

The application of biomarker research in the geologic record has dealt with the derivative hydrocarbons as found in petroleum, coals, and sedimentary rocks. Reports on biomarkers in discrete fossils compared to the host rocks are sparse because (1) previous studies focused on the highly degraded geoterpenoids, i.e. saturated and aromatic hydrocarbons, and (2) the preservation potential of polar compounds (natural product bioterpenoids ) was believed to be low. Flowever, recent investigations of conifer fossils demonstrated that unaltered natural product terpenoids can be preserved in resin material.This will be illustrated here with an example. 

The botanical species exploited in the past for the collection of resins vary according to the geographical area, and thus, the availability of adequate reference materials of a known botanical origin is crucial for resin identification. Pine resin and resin-derived pitch, mastic, frankincense, myrrh, benzoe, and birch bark tar are the most common terpenoid materials in archaeological artifacts from the Mediterranean area. Terpenic resin composition depends on aging and exposure to air and light, so the biomarkers used for their identification are... 

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