A syn-ent-labdadiene derivative with a rare spiro-β-lactone function from the male cones of Wollemia nobilis

Abstract

An undescribed labdane-like diterpene with a rare spiro-β-lactone function was identified from the ethanol extract of the male cones of the coniferous tree Wollemia nobilis. This spirolabdadienolide (IUPAC name: syn-ent-8(17),13-labdadien-19,18-olid-15-oic acid methyl ester; trivial name: wollemolide), was isolated by means of traditional and high performance chromatography techniques and structurally elucidated through NMR and MS. In addition, six further known metabolites were evidenced in the extract. Wollemolide, which may be considered an additional chemotaxonomic marker, and 4'-O-methyl-scutellarein, a simple flavonoid, had not been isolated in our previous phytochemical study on the same plant organ. This demonstrates how the molecular pattern of a plant species is in continuous movement and changes with the passing of time according to the climate of the year.

Keywords: Araucariaceae; Diterpenes; HPLC; K.D.Hill & J.M.Allen; MS; NMR; Spiro-labdane derivative; Wollemia nobilis W.G.Jones.