Evaluation of the chemical composition of essential oils with respect to the maturity of flower heads of Arnica montana L. and Arnica chamissonis Less. cultivated for industry

Abstract

The aim of the studies was to evaluate the chemical composition of essential oils extracted from different mature flower heads of Arnica montana L. and Arnica chamissonis Less. cultivated for industry. The impact of different stages of flower development on the quantity and chemical composition of volatile oils of Arnica montana L. and Arnica chamissonis Less. in eastern Poland were studied. The flower heads were harvested in four different development phases and the chemical composition of essential oils was investigated by GC/MS. Fifty compounds in the case of A. montana and 62 components in the case of A. chamissonis constitued over 90% of the total oil content.In the case of the two plant species studied, the flower head maturity determined the quantity and chemical composition of oils. The content of volatile oils in flower heads of A. montana was in the range from 0.158% to 0.195% and in A. chamissonis from 0.137% to 0.194%. The highest content of volatile oils in the flower heads of the two plant species studied was noted in the full flowering phase, when ligulate florets were opened, and up to half of the disc of tubular florets were opened. Differences in the volatile oil content were noted between the species studied only in the stage of yellow buds, whereas in the other stages the contents were similar. E-caryophyllene, alpha-pinene, isopropyl hexadecanoate, farnesyl acetate, alpha-cis-bergamotene, and decanal are the main components that determined the oil chemical differentiation. Generally, higher amounts of E-caryophyllene, farnesyl acetate, and germacrene D were detected in the flower heads of A. montana in relation to A. chamissonis. Among the main volatile oil components, isopropyl hexadecanoate and alpha-pinene were present only in the flower heads of A. chamissonis, while alpha-cis-bergamotene was only noted in A. montana. The investigations of A. montana volatile oils in the flower heads have shown the existence the differences in the chemical profile in relation to other European populations of this species.