Diversity in the composition of monoterpenoids of Origanum microphyllum (Labiatae)

The variability in the composition of the volatile compounds of Origanum microphyllum, a species endemic to Crete, was examined. Headspace analysis was carried out on leaves from five natural populations and subsequently from the same plants from uniform cultivation. Plants were rich in cis-sabinene hydrate (3-68%), sabinene (3-45%) and trans-sabinene-hydrate (0.5-34%). Four chemical profiles were distinguished, the extremes being either rich in sabinene and trans-sabinene-hydrate, or rich in cis-sabinene-hydrate. Furthermore, different chemical profiles were present in all populations to varying proportions, which explains the high variation observed within each population and the apparent small variation between them. The pattern of distribution of the different profiles among populations suggested a possible closer relation between neighbouring populations. There is a strong evidence of genetic control in the composition of the volatiles of O. microphyllum since it remained nearly unchanged in cultivation when the same plants were examined a year later. (C) 2002 Elsevier Science Ltd. All rights reserved.