Salicassin, an unprecedented chalcone-diterpene adduct and a quinone methide triterpenoid from maytenus salicifolia

Abstract

In continuation of our work on Maytenus salicifolia, we report herein the isolation and structural elucidation of two new compounds, salicassin (1), a diterpene-chalcone adduct with an unprecedented C-framework, and (16β)-16-hydroxypristimerin (2), a quinone methide triterpenoid. Their structures were elucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR techniques (COSY, ROESY, HSQC, and HMBC). In addition, 22 known compounds were isolated and characterized by comparison of their spectra with reported data. Compound 2, structurally related to the well known cytotoxic quinone methide triterpenoids, exhibited an antiproliferative effect on HeLa, A-549, and HL-60 human cell lines, with IC50 values of 2.2, 3.2, and 2.7 μM, respectively. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.