Tirucalla-5,24-dien-3β-ol [(13α,14β,17α,20S)-lanosta-5,24-dien-3β-ol] and three other Δ5-unsaturated tirucallanes from the roots of Bryonia dioica Jacq.: the first naturally occurring C-10 methylated tetracyclic triterpene alcohols with a Δ5-monounsaturated skeleton

Four novel triterpene alcohols with a Δ5-unsaturated tirucallane-type skeleton, i.e. tirucall-5-en-3β-ol, tirucalla-5,24-dien-3β-ol, 24-methyltirucalla-5,24(241)-dien-3β-ol and (24S)-24-methyltirucalla-5,25-dien-3β-ol, have been isolated from the roots of Bryonia dioica Jacq. (Cucurbitaceae). The structures have been determined by spectroscopic and chromatographic methods. These compounds are the first examples of naturally occurring C-10 methylated triterpenes with a Δ5-monounsaturated skeleton.