Composition and Variability of Leaf Oil from Monodora crispata-13C NMR Identification of Heat-sensitive Compounds

The composition of four samples of essential oil isolated from the leaves of individual Monodora crispata trees growing wild in an Ivorian forest (Adiopodoume) were investigated by a combination of chromatographic (GC(RI)) and spectrometric (GC-MS, C-13 NMR) techniques. In total, fifty-seven compounds accounting for 92.3-98.7% of the whole composition were identified. These oils were characterized by the preeminence of sesquiterpene hydrocarbons and the content of the main components varied substantially from sample to sample. Two samples were largely dominated by germacrene D (67.3% and 76.3%, respectively), a third sample was represented by germacrene D (28.3%), germacrene C (14.3%), delta-elemene (12.1%) and beta-elemene (9.3%) and the fourth sample was characterized by -dimethylallylindole (15.1%), germacrene D (12.0%) and cyperene (7.8%). C-13 NMR spectroscopy was particularly efficient for the identification of heat-sensitive compounds.