Identification of maloyl glucans from Euphorbia tirucalli by ESI-(−)-FT-ICR MS analyses

Abstract

Euphorbia tirucalli aerial parts are popularly used in Brazil for cancer treatment. The elution of the aqueous extract of the plant on silica gel C-18 cartridge furnished a water-soluble fraction, which was analyzed directly into the electrospray ionization (ESI) source combined with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and characterized as a mixture of malic acid glycosides 1–5. The compounds were detected in their deprotonated form [M−H]−, where their exact mass (mass error lower than 1ppm), molecular formula (CnHhOo), double bond equivalent (DBE) and connectivity were determined from ESI-(−)-MS and ESI-(−)-MS/MS experiments. The presence of malic acid and glucose, as part of the structures, could originate from crassulacean acid metabolism (CAM) of the plant.