Share
Export Citation
Spiro-meroterpenoids, Syzygioblanes D-H, Isolated from Indonesian Medicinal Plant Syzygium oblanceolatum
Koga N.
Journal of Natural Products
Q1Abstract
Syzygioblanes A–C ( 1 – 3 ), isolated from the Indonesian traditional herbal medicine Syzygium oblanceolatum ( S. oblanceolatum ), are meroterpenoids with a spiro ring formed through a [4 + 2] cycloaddition of the flavanone desmethoxymatteucinol with cyclic sesquiterpenoids. Our ongoing phytochemical investigation of S. oblanceolatum resulted in the isolation of five additional spiro-meroterpenoids, syzygioblanes D–H ( 4 – 8 ), which are hybrids of the same flavanone with eudesmane/cadinane-type sesquiterpenoids. A possible biosynthetic pathway involves enzymatic dearomative hydroxylation of desmethoxymatteucinol followed by [4 + 2] cyclization of the resulting diene with a cyclic sesquiterpene containing an exocyclic methylene to form the unique spiro ring in the syzygioblane molecule. The isolated syzygioblanes F ( 6 ) and G ( 7 ) demonstrated collateral sensitivity by inhibiting the growth of multidrug-resistant tumor cell lines more than the related chemosensitive tumor cell lines.