NEOCLERODANE DITERPENOIDS FROM TEUCRIUM-SANDRASICUM

Six new neo-clerodane diterpenoids, teusandrins A-F, and two known com pounds, teucjaponin B and its 6-O-acetyl derivative, were isolated fro m the aerial parts of Teucrium sandrasicum. The structures of the new diterpenoids [(12S)-6 alpha,19-diacetoxy-4 alpha,18; 15,16-diepoxy-8 b eta,10 beta-dihydroxy-neo-cleroda-13(16), 14-dien-20,12-olide (teusand rin A), (12S)-19-acetoxy-4 alpha,18; 15,16-diepoxy-6 alpha,8 beta,10 - 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-die n-20, 12-olide (teusandrin D), (12S)-4 beta,10 beta; ,19-dihydroxy-6-o xo-neo-cleroda-13(16),14-dien-20, 12-olide (teusandrin E) and (12S)-4 beta,10 beta; 15,16-diepoxy-6 -trihydroxy-neo-cleroda-13(16),14-dien-2 0,12-olide (teusandrin Fl] were established by chemical and spectrosco pic means, The probable identity between teusandrins A and B, and the previously described sandrasin A and 6-deacetylsandrasin A, respective ly, is also discussed. (C) 1997 Elsevier Science Ltd. All rights reser ved.