By Gilles Figuérédo, Jean-Claude Chalchat and Bernard Pasquier

Abstract: Abstract: Analysis by GC and GC/MS of the oil of Origanum dayi grown in France from seeds collected from the desert of Judea in Israel, isolated by water distillation, led to the identification of 68 constituents. The oil was characterized by high proportions of 1,8-cineole (18.2-26.8%), terpinen-4-ol (16.1-21.6%) and α-terpineol (12.9-16.8%). Key Word Index: Origanum dayi, Lamiaceae, essential oil composition, 1,8-cineole, terpinen-4-ol, α-terpineol.

Introduction
Origanum dayi Post is classified by Ietswaart (1) in Section VII Campanulaticalix of Group C. A first work was produced by Lawrence (2). In Section VII, only the oil of O. ramonense Danin (3) obtained by steam distillation and trapping with dichloromethane or SPE has been studied. The oil obtained by steam distillation was composed of 80% alcohols, principally α-terpineol (42%), terpinen-4-ol (17%), cis-sabinene hydrate (13%) and eugenol (3.6%). Those constituents obtained by SPE contained mainly 1,8-cineole (17.5%), γ-terpinene (14.7%), terpinen-4-ol (13.9%), α-terpinene (9.3%) and α-terpineol (6.8%).

Origanum dayi from the desert of Judea grows on the stony banks of the wadis and roads up to an altitude of 800 m. When cultivated, it demands a well-drained soil and tolerates high sun exposure. It grows fairly slowly and flowers sparingly the first year. Its habit is first erect, but later its main branches become prostrate, sending out secondary vertical branches with a spreading erect habit. Its eucalyptus-like scent is remarkably strong. This oregano can be used as an ornamental pot or rockery plant.

Here we study the oils of O. dayi grown at the Conservatoire National de Plantes à Parfum Médicinales, Aromatiques et Industrielles (CMPPMAI) from seeds collected in the desert of Judea.