Metajapogenins A-C, Pregnane Steroids from Shells of Metaplexis japonica.

ABSTRACT

Phytochemical investigation of the shells of Metaplexis japonica (Thunb.) Makino, belonging to the family of Apocynaceae, afforded three new pregnane steroids, metajapogenins A-C, along with three known compounds. The structures of the new compounds were elucidated as 12ß,14ß,17ß-trihydroxypregna-3,5-dien-7,20-dione, 12ß,14ß,17ß,20ß-tetrahydroxypregna-3,5-dien-7-one; 3ß,12ß,14ß,17ß-tetrahydroxypregn-5-ene-7,20-dione on the basis of extensive spectroscopic evidence derived from 1D; 2D-NMR experiments and mass spectrometry. The known compounds included pergularin; 12-O-acetylpergularin; and pergularin-3-O-ß-d-oleandropyranose; which were identified for the first time in the shells of M. japonica.