Sesquiterpene Hydrocarbons of the essential oil of Actinolema macrolema Boiss

The essential oils obtained by steam distillation in the first three hours and following three hours from crushed fruits and dried leaves of Actinolema macrolema Boiss. collected from its natural habitat in Konya, Turkey, were analysed by gas chromatography and gas chromatography-mass spectrometry. 68 components have been characterized representing 93% of the leaf oil. 33 components were characterized representing 95% of the first fraction and 90% of the second fraction.

Identification of some of the compounds was carried out using techniques such as GC-MS, ¹H-NMR and ¹³C-NMR. The sesquiterpene hydrocarbons guaia-5,7(11)-diene, selina-3,7(11)-diene and juniper camphor were isolated from the oils by column chromatography. The occurrence of guaia-5,7(11)-diene is reported for the first time in nature.

Guaia-5,7(11)-diene (37% and 30%), germacrene-B (25% and 21%), selina-3,7(11)-diene (12% and 12%) and 4,6-guaiadiene (10% and 8%) were found as major components in the oil of the first three hours and the following three hours, respectively. In the leaf oil, 1-octadecanol (24%) and hexadecanoic acid (19%) were identified as the major components.

Antimicrobial activities of the fruit oils on Gram negative, Gram positive microorganisms and the yeast Candida albicans using the microdilution method have been determined. The distillation product obtained within the first three hours showed a good inhibitory effect on Staphylococcus epidermidis (MIC=62.5µg/ml). The two fruit essential oils had the same inhibitory effect on C. albicans as the standard antifungal used (MIC=125µg/ml).

Acknowledgements: This work is part of the MSc thesis of GK.