Sesquiterpenes from Cymbopogon proximus

In addition to four previously reported compounds: proximadiol (1), 5alpha-hydroxy-beta-eudesmol (2), 1beta-hydroxy-beta-eudesmol (4) and 1beta-hydroxy-alpha-eudesmol (5), two new sesquiterpenes, 5alpha-hydroperoxy-beta-eudesmol (3) and 7alpha,11-dihydroxycadin-10(14)-ene (6) were isolated from the unsaponifiable fraction of the petroleum ether extract of Cymbopogon proximus STAPF. Isolation of compounds 2, 4 and 5 from the genus Cymbopogon is reported for the first time. The structure elucidation of these compounds was based primarily on 1D and 2D-NMR analyses.