Phytochemical analysis and biological activities of Wollemia nobilis W.G.Jones, K.D.Hill & J.M.Allen leaves collected in the Botanical Garden of Rome

In this work, a preliminary screening of the bioactivities of an ethanolic extract obtained from the leaves of Wollemia nobilis W.G.Jones, K.D.Hill & J.M.Allen was carried out to explore its potential pharmaceutical applications. In particular, the radical scavenging, chelating, reducing antiglycative, antimicrobial and antifungal activities as well as the inhibitory effects on the production of aflatoxin B1 in Aspergillus flavus Link were evaluated. The extract demonstrated promising biological activities, although generally with lower potency compared to the positive control. To identify the metabolites potentially responsible for these effects, the extract was subjected to phytochemical analysis evidencing the presence of eight known compounds. Among them, 15-agathic acid methyl ester (1) and ladanein (5) were reported for the first time in this species. Furthermore methyl-(E)-communate (2), 7,4′,7″,4‴-tetra-O-methyl-robustaflavone (6), agathisflavone (7) and quinic acid (8) were detected for the first time in the leaf tissue of W. nobilis. Their presence and the presence of isocupressic acid (3) and acetyl-isocupressic acid (4) in this species highlights the taxonomic correlations within the Araucariaceae family and suggests a possible contribution of these compounds in the bioactivities of the extract. However, further studies are required to confirm these contributions and to elucidate their mechanisms of action.