Identification of phenolic compounds in Prosopis juliflora by liquid chromatography tandem mass spectrometry

Abstract

A substantive study on the identification of phenolic compounds present in Prosopis juliflora was undertaken. P. juliflora is known to be highly adapted to dry lands because of its deep taproots which tolerate dry and waterlogged soils. However, because of its invasive nature, it has spread to undesirable areas like sea shores, arable lands and roads becoming a great menace. Towards its valorization, this study aimed at identifying the various phenolic compounds present in it. Plant samples were collected from three different geographical areas in Kenya; Baringo, Garissa and Turkana Counties. Its acetonic extracts were thereafter analyzed using a reversed- phase liquid chromatography coupled to electrospray ionization – tandem mass spectrometry. Identification of the compounds present was achieved by comparison of experimental retention times and UV-MS spectra to bibliographic data and standard compounds. Twenty chemical compounds were tentatively identified out of which fifteen were found either as flavonoid aglycones or some of their glycosylated forms. For the first time, a new compound believed to be a B-type proanthocyanidin of mesquitol was identified based on the MS/MS diagnostic ions that resulted from retro-Diels-alder reaction, quinone methide cleavage and heterocyclic ring fission. The results illustrate a rich array of phenolic compounds present in P. juliflora