The Lipophilic Extractives of an Interglacial Fossil Picea abies from Zeifen (Germany)

Abstract

Summary A fossil Picea abies from Zeifen (Germany), 100,000 years old and still presenting good physical and anatomical properties, is analysed with respect to its lipophilic content. Comparisons are made with a recent Picea abies, with a subfossil larch and with Taxodioxylon gypsaceum fossils ranging from 1.7 to 20 million years ago. Due to the relatively small age and the low degree of degradation, terpenes having structures intermediate between the original compounds and the final terpanes are looked for. Lipophilic components obtained from the fossil Picea abies by extraction with dichloromethane include linear alkanes, fatty acids, high MWs alcohols and terpenoids such as sesquiterpanes, diterpanes and diterpenoids. Some of extractive components result unchanged after the process of ageing while others correspond to substances derived by a process of hydrolysis of original extractives occurring in recent Picea abies. Diterpanes (norabietatriene, norpimarane, retene and α-phyllocladane) correspond to those present in most fossils of conifers, even if a trend to the formation of demethylated compounds is observed. Diterpenoids, on the contrary, are present exclusively as the dehydroabietic acid structure, the form preceding or responsible of those of most diterpanes, while different structures are not found. Since intermediate compounds with structures different from the abietic one are absent they might be looked for in younger fossils. The presence of a large amount of terpanes places this fossil rather closer to Taxodioxylon gypsaceum samples than to the subfossil larch.