Qualitative and quantitative analysis of the active components of the essential oil from Brickellia veronicaefolia by nuclear magnetic resonance spectroscopy.

The composition of the spasmolytic essential oil of the medicinal species Brickellia veronicaefolia was established by NMR spectroscopy in addition to GC-MS analysis and HPLC studies. Seven major compounds, representing ca. 86% of the oil, were identified as benzyl 2,6-dimethoxybenzoate (1), 2-hydroxybenzyl 2'-methoxybenzoate (2), chamazulene (3), beta-caryophyllene (4), germacrene D (5), bicyclogermacrene (6), and beta-eudesmol (7). A sensitive and accurate analytical 1H NMR method has been developed for the quantification of the major compounds in the essential oil of B. veronicaefolia. The method was validated using benzyl 2,6-dimethoxybenzoate (1) and beta-caryophyllene (4), two of the active principles in the oil, and successfully applied to the determination of these pharmacologically active compounds in three different batches of the oil collected in different geographical regions and/or seasons.