N-alkylamide profiling of Achillea ptarmica and Achillea millefolium extracts by liquid and gas chromatography-mass spectrometry

Abstract

Achillea millefolium and Achillea ptarmica are both plants belonging to the Asteracea family and are traditionally used for their medicinal properties. It has already been shown that some N-alkylamides (NAAs) are responsible for these pharmacological actions. Therefore, in the present study, the NAA content of the two plants was analytically characterised. Different extracts were prepared from the roots, the leaves, the stems and the flowers. The structures of NAAs have been assigned in ethanolic extracts of Achillea millefolium and Achillea ptarmica using high performance liquid chromatography - electrospray ionisation - mass spectrometry (HPLC-ESI-MS) and gas chromatography - electron impact - mass spectrometry (GC-EI-MS). Using both analytical techniques, the structures of 14 and 15 NAAs have been assigned in Achillea ptarmica and Achillea millefolium, respectively. Structures of two new NAAs, previously never observed in Achillea ptarmica, were assigned: deca-2E,6Z,8E-trienoic acid 2-methylbutylamide (homospilanthol) or a related isomeric compound and deca-2E,4E-dienoic acid N-methyl isobutylamide. The structure of homospilanthol or a related isomeric compound was also assigned in Achillea millefolium for the first time.

Keywords: Achillea millefolium; Achillea ptarmica; GC–EI–MS; HPLC–ESI–MS; N-alkylamides.

Fig. 1

TIC of Achillea ptarmica obtained using HPLC–ESI–MS.

Fig. 2

MS² fragmentation spectra (CID) of N-alkylamides in the A. ptarmica extract.

Fig. 3

MS² spectra of deca-2E,6Z,8E-trienoic acid 2-methylbutylamide or homospilanthol (compound P8) with [M+H]⁺= m/z 236.

Fig. 4

MS² spectra of deca-2E,4E-dienoic acid N-methyl isobutylamide (compound P14) with [M+H]⁺= m/z 238.

Fig. 5

TIC of Achillea ptarmica obtained using GC–EI–MS.

Fig. 6

TIC of Achillea millefolium obtained using HPLC–ESI–MS.

Fig. 7

MS² fragmentation spectra (CID) of N-alkylamides in the A. millefolium extract.

Fig. 8

TIC of Achillea millefolium obtained using GC–EI–MS.