A new meroterpenoid isolated from roots of Ptaeroxylon obliquum Radlk.

The roots of Ptaeroxylon obliquum Radlk. (Rutaceae) afforded a new meroterpenoid, ptaerobliquol, together with chromones, ptaeroxylinol acetate and peucenin, and coumarins, scopoletin and prenyletin. Ptaerobliquol was isolated using centrifugal partition chromatography followed by silica gel column and identified as 7a,8,9,9a,9b, 10a-heptahydro-4H-10,10-dimethyl-1,7-dioxa-5-hydroxy-2-hydroxymethylcyclobutyl[1,2,3:3,3a,4]indeno[5,6-a]naphtalen-4-one by extensive NMR and single crystal X-ray analyses. A biosynthetic pathway is proposed for this new compound. Activity of ptaerobliquol toward Toxoplasma gondii was investigated and a moderate activity was found with an IC50 of 5.13 mu M. (C) 2013 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.