Constituents of the seeds of Swietenia mahagoni Jacq. I. Isolation, structures, and 1H- and 13C-nuclear magnetic resonance signal assignments of new tetranortriterpenoids related to swietenine and swietenolide.

Abstract

Eighteen new tetranortriterpenoids were isolated from the cotyledons of Swietenia mahagoni (Meliaceae) along with the known tetranortriterpenoids. Among them, the structures of wight new compounds, swietenins B, C, D, E, and F, 3-O-acetylswietenolide, 6-O-acetylswietenolide, and 3-O-tigloyl-6-O-acetylswietenolide, were determined by the use of two-dimensional nuclear magnetic resonance (2D NMR) techniques. Detailed analyses of the 1H- and 13C-NMR spectra of the ten known compounds were also performed.