Fitochimica e chemotassonomia di un fossile vivente: Wollemia nobilis W.G. Jones, K.D.Hill & J.M.Allen

In this paper, we present the first phytochemical analysis ever done on the arboreal coniferous species (Aracauriaceae family) called Wollemia nobilis W.G. Jones, K.D.Hill & J.M.Allen and in particular we focused on the constituents of the polar part of his male fruits. The species is considered a living fossil and it was believed to be disappeared until 1994 when a specimen was found by chance in Australia. In the world there are very few examples, and one of these is located in the botanical garden of Rome which is the subject sample of the study . Previous work on this species have mainly focused on botanical aspects and on the essential oil while only a few have studied the polar part and not in all its entireness considering only certain classes of natural organic compounds. The reason of our study was right that: to give the species a first and absolute phytochemical identity and to begin considering its chemotaxonomic aspects to be able to assess if the botanical classification is in accordance with what shown from a phytochemical point of view. Our analysis was performed following a classic protocol: extraction of the plant material with ethanol, isolation and recognition of the constituents through classical chromatographic techniques such as column chromatography and spectroscopic techniques such as NMR Spectroscopy and Mass Spectrometry. From this procedure, we isolated and identified seven substances belonging to four major classes of natural compounds. These compounds are respectively isocupressic acid (1), acetyl-isocupressic acid (2), methyl- (E) -communate (3), sandaracopimaric acid (4) for the diterpenoid, 7-4 '' '- dimethoxy-agathisflavone (5) for the biflavonoids, shikimic acid (6) for the cicloexencarboxylic acids and arginine (7) for the amino acids. The recognition of these compounds is remarkable because all of them represent compounds reported for the first time in the species, except for the 7-4 '' '- dimethoxy-agathisflavone (6). Moreover isocupressic acid and acetyl-isocupressic acid, which had already been identified in other conifer families, were reported in this study for the first time in a species comprised in Araucariaceae. On the other hand, methyl- (E)-communate and sandaracopimaric acid have already been found in the family as well as the shikimic acid while arginine is a common amino acid of plants in general. From a chemotaxonomic standpoint, the presence of these compounds shows the correct botanical classification of the species which in fact presents phytochemical traits in common with taxonomic entities belonging to the same family.