Studies towards the detection and identification of sesquiterpene pyridine alkaloids in Peritassa campestris by mass spectrometry

Abstract

Sesquiterpene pyridine alkaloids were analysed in Peritassa campestris by mass spectrometric techniques such as ESI-MSMS and GCMS. Ten alkaloids previously isolated from this plant and fully identified by other physical methods, including NMR spectroscopy and X-ray diffraction, were carefully studied by MS. It was observed that the low mass ions detected at m/z 178 and 206 in both MS technique tested were characteristic of evoninic and wilfordic acids, which are part of the macrolactone in these sesquiterpene alkaloids. The intensity of a fragment ion detected at m/z 93 in CAD, and especially in EI, spectra was found to be diagnostic in distinguishing between evoninoates and wilfordates. Running parent/daughter or GCMS experiments enabled these substances to be detected in crude fractions of P. campestris. Parent ion scans of m/z 206 were very as a first analysis of an alkaloid mixture.