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 [(12S)-6 alpha,19-diacetoxy-4 alpha,18; 15,16-diepoxy-8 beta,10 beta-dihydroxy-neo-cleroda-13(16), 14-dien-20,12-olide (teusandrin A), (12S)-19-acetoxy-4 alpha,18; 15,16-diepoxy-6 alpha,8 beta,10 beta-trihydroxy-neo-cleroda-13(16),14-dien-20,12-olide (teusandrin B);(12S)-4 alpha,19; 15,16-diepoxy-6 alpha,8 beta,10 beta,18-tetrahydroxy-neo-cleroda-13(16), 14-dien-20,12-olide (teusandrin C), (12S)-4 alpha,19; 15,16-diepoxy-6 alpha,10 beta,18-trihydroxy-neo-cleroda- 13(16),14-dien-20, 12-olide (teusandrin D), (12S)-4 beta,10 beta; 15,16-diepoxy-18,19-dihydroxy-6-oxo-neo-cleroda-13(16),14-dien-20, 12-olide (teusandrin E) and (12S)-4 beta,10 beta; 15,16-diepoxy-6 alpha;18,19-trihydroxy-neo-cleroda-13(16),14-dien-20,12-olide (teusandrin Fl] 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