Essential oils and hexane extracts from leaves and fruits of Cistus monspeliensis. Cytotoxic activity of ent-13-epi-manoyl oxide and its isomers

Essential oils and hexane extracts from Cistus monspeliensis L. leaves and fruits were analysed by CC-MS. Manoyl oxide and its isomers, 3 beta -hydrox y-manoyl oxide, 3 beta -hydroxy-13-epi-manoyl oxide, as well as 3 beta -ace toxy-13-epi-manoyl oxide were detected for the first time in C. monspeliens is L. Ent-13-epimanoyl oxide was isolated from the hexane extract of leaves and its structure was determined using spectroscopic methods. In vitro cyt otoxic activity of ent-13-epi-manoyl oxide and mixtures of manoyl oxide iso mers at 10(-4) M concentrations ranged from 11.1 to 32.2% of the activity f or a vinblastine control evaluated against nine leukemic cell lines. The re sults showed that the manoyl oxide isomer mixtures as well as ent-13-epi-ma noyl oxide exhibited a slight growth inhibiting activity.