New tirucallane-type triterpenes from Dysoxylum variabile

  • J Nat Prod. 2001 Feb;64(2):159-63. doi: 10.1021/np0002841.
H Liu  1 ,  J Heilmann ,  T Rali ,  O Sticher
Affiliations
  • 1. Department of Applied BioSciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, CH-8057 Zürich, Switzerland.
PMID: 11429992 DOI: 10.1021/np0002841
Abstract

Eight new tirucallane-type Triterpenes, dyvariabilins A-H (1-8), three known tirucallanes, niloticin (9), dihydroniloticin (10), and tirucalla-7,24-diene-3 beta,23-diol (11), and two known Sesquiterpenes, 1-(1-hydroxy-2-methylpropyl)-3a-methyl-7-methyleneoctahydroinden-4-ol and (+)-aphanamol I, were isolated from the stem bark of Dysoxylum variabile. Tirucallanes 1 and 11 with an allylic hydroxy group in the side chain and dyvariabilin C (3) with an alpha-epoxy group at positions 7 and 8 showed high instability in acidic medium and formed five hitherto unknown semisynthetic tirucallanes. Dyvariabilins B (2) and C (3) as well as the mixtures of dyvariabilins E and F (5 and 6) and dyvariabilins G and H (7 and 8) showed weak cytotoxicity against KB cells.

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