Isolation and structure of regelin and regelinol, new antitumor ursene-type triterpenoids from Tripterygium regelii.

Abstract

Regelin (1a), a new antitumor ursene-type triterpenoid, the major principle, and another new ursene-type regelinol (1c) were isolated together with oleanene-type regelide (2) from the roots of Tripterygium regelii. The respective structures of 1a and 1c were determined, by 1H- and 13c-NMR spectrometric studies and X-ray analysis of 1a, to be the methyl ester of 3-oxo-22.alpha.-hydroxy-urs-12-en-30-oic acid and its 23-hydroxy analogue. 2 was found to be identical with wilforlide A or abruslactone A by comparing their physico-chemical data.