Chemical Variation Among Indigenous Populations of Foeniculum vulgare var. vulgare in Israel

Abstract

Abstract: The composition of hexane extract constituents of ripe mericarps (“achenes”) of eleven indigenous populations of Foeniculum vulgare var. vulgare (Apiaceae) was studied. Natural populations were selected along a gradient of annual rainfall from ca. 1000 mm in the northern region down to 125 mm in the Negev desert. Eighteen constituents, with estragole, trans-anethole, fenchone, limonene and α-pinene as the major components were separated by GC-MS. Characterized by the level of estragole and trans-anethole, four different groups were obtained: (1) Highest estragole (63%) and the lowest trans-ane-thole (3%) characterized the population of Mt. Meron; (2) estra-gole (39-47%) and trans-anethole (17-29%) in 3 mountainous populations; (3) estragole (21-29%) and trans-anethole (38-49%) in the coastal and lowland populations; (4) two exceptional populations with the lowest content of estragole (ca.8%) and high content of trans-anethole (55 and 74%). A reversed association between the content of estragole and trans-anethole suggests a common precursor. In habitats with a high precipitation, the content of estragole was high and that of trans-anethole was low, and vice versa under limited rainfall. It is proposed that the composition of oleoresins of F. vulgare var. vulgare could be governed by environmental conditions. Never-theless, it is not ruled out that genetic variations account for the recorded differences.