Neo-clerodane diterpenoids from Teucrium sandrasicum

Abstract

Six new neo-clerodane diterpenoids, teusandrins A–F, and two known compounds, teucjaponin B and its 6- O-acetyl derivative, were isolated from the aerial parts of Teucrium sandrasicum. The structures of the new diterpenoids [(12 S)-6α,19-diacetoxy-4α,18; 15,16-diepoxy-8β,10β-dihydroxy- neo-cleroda-13(16),14-dien-20,12-olide (teusandrin A), (12 S)-19-acetoxy-4α,18; 15,16-diepoxy-6α,8β,10β-trihydroxy- neo-cleroda-13(16), 14-dien-20,12-olide (teusandrin B), (12 S)-4α,19; 15,16-diepoxy-6α,8β,10β,18-tetrahydroxy- neo-cleroda-13(16),14-dien-20,12-olide (teusandrin C), (12 S)-4α,19; 15,16-diepoxy-6α,10β,18-trihydroxy- neo-cleroda-13(16), 14-dien-20,12-olide (teusandrin D), (12 S)-4β,10β; 15,16-diepoxy-18,19-dihydroxy-6-oxo- neo-cleroda-13(16), 14-dien-20,12-olide (teusandrin E)and (12 S)-4β,10β; 15,16-diepoxy-6α,18,19-trihydroxy- neo-cleroda-13(16), 14-dien-20,12-olide (teusandrin F)] were established by chemical and spectroscopic means. The probable identity between teusandrins A and B, and the previously described sandrasin A and 6-deacetylsandrasin A, respectively, is also discussed. © 1997 Elsevier Science Ltd. All rights reserved