Plant-part anatomy related composition of essential oils and phenolic compounds in Chaerophyllum coloratum, a Balkan endemic species

Abstract

Chaerophyllum coloratum is an endemic plant for the Western Balkans. Despite of its common occurrence in the Sub-Mediterranean part of Dinaric countries, knowledge about its structure and biologically active compounds is rather poor. The plant material was collected in Montenegro. The structure was studied on paraffin sections, as well as on native sections stained with standard reagents for histochemical analysis. Chemical analyses of the essential oils from its leaves, flowers, roots, stems and fruits were performed. The total phenolic, flavonoid and tannin contents in different plant organs were determined, as well, in order to give an insight in the pattern of secondary metabolites distribution. Although it was shown that morphologically and ecologically Chaerophyllum coloratum differed significantly from other species of the genus native in the flora of the Western Balkans, it shared common structural features of the genus. In a comparative analysis of 33 anatomical characters of C coloratum and six previously studied Chaerophyllum species, C coloratum clustered with Chaerophyllum aureum. In addition it was closely linked with two other species of Chrysocarpum section: Chaerophyllum bulbosum and Chaerophyllum aromaticum. Histochemical and chemical analysis of secondary metabolites showed the presence of essential oil in all studied plant organs, but differing both in composition and content of individual compounds. The essential oil from the roots is characterized by a high content of monoterpene myrcene (72.18%). In the case of stem monoterpens beta-(E)-ocimene (33.59%), beta-(Z)-ocimene (20.43%) and terpinolene (10.77%) were predominant compounds, while the principal constituents in the oil of leaves were identified as spathulenol (10.19%), p-cymene-8-ol (9.45%) and p-cymene (7.6%). Monoterpenes terpinolene (17.08%), p-(Z)-(E)-ocimene (6.96%) were identified as the main constituents of the flower oil, while in the fruits, the constituents with the highest amount were caryophyllene oxide (6.93%), (Z)-beta-farnesene (5.92%), (E)-pinocarveol (5.56%) and myrtenol (5.25%).