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 structuralelucidation of two new compounds, salicassin (1), a diterpene-chalcone adduct with an unprecedented C-framework, and (16b)-16-hydroxypristimerin (2), a quinone methide triterpenoid. Their structures wereelucidated 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 bycomparison of their spectra with reported data. Compound 2, structurally related to the well knowncytotoxic quinone methide triterpenoids, exhibited an antiproliferative effect on HeLa, A-549, and HL-60 human cell lines, with IC50values of 2.2, 3.2, and 2.7 mm, respectively.