Cardanols, long chain cyclohexenones and cyclohexenols from lannea schimperi (anacardiaceae)

Abstract

Alkenyl cyclohexenones (1a-d), alkenyl cyclohexenols (2a-c and 3b-d) and cardanols (4a-d) were isolated from the stem bark and root of Lannea schimperi. The alkenyl cyclohexenones (1a and 1d) and cardanols (4a and 4d) have side chains which have not been reported previously, in combination with the core skeletal structures. In addition, compounds 2a-c and 3b-d are all new cyclohexenols. Also isolated were the triterpenes, taraxerone and taraxerol, and sitosterol. The suite of compounds isolated (cyclohexenones and cyclohexenols) make up a nice biosynthetic pathway to the cardanols. The 5-[alkenyl]-4,5-dihydroxycyclohex-2-enone mixture (1a-d) exhibited good in vitro cytotoxicity against the Chinese Hamster Ovarian mammalian cell-line. The compounds were identified mainly from GCMS and NMR spectroscopic techniques.