Chemical characterization of wild growing Origanum vulgare populations in Montenegro

Abstract

In order to make chemical characterization of two Origanum vulgare L. subspecies in Montenegro, the essential oils of five wild growing populations were analyzed. Among 67 oil constituents, in O. vulgare subsp. hirtum dominant one was oxygenated monoterpene carvacrol (74.3%), while in O. vulgare subsp. vulgare prevailed sesquiterpene hydrocarbons: germacrene D (15.4-27.9%) and β-caryophyllene (7.7-14.6%), and among oxygenated monoterpenes: α- terpineol (4.8-17.8%), linalyl acetate (0.5-9.6%), linalool (3.0-8.8%), thymol (0.2-8.3), terpinene 4-ol (1.5-8.3%). Several of the main essential oil constituents appeared to be highly intercorrelated. Strong positive correlations (r > 0.70; P < 0.01) were observed between α-terpineol and linalyl acetate, α- terpineol and thymol, linalyl acetate and thymol, γ-terpenene and carvacrol, (E)-β-ocimene and β-bisabolene, while strong negative correlations (r < -0.70; P < 0.01) were evidenced between γ-terpenene and β-caryophyllene, γ-terpenene and germacrene D, p-cymene and germacrene D. Multivariate analyses allowed the grouping of the populations into three distinct chemotypes. Population P5 (Origanum vulgare subsp. hirtum) was distinguished from O. vulgare subsp. vulgare populations by predominance of carvacrol, while within the typical subspecies the population P1 (Boljevići) separated from P2 (Radovče), P3 (Lipovo) and P4 (Grahovo) by high oil levels of α-terpineol, linalyl-acetate and thymol.