UPLC-qTOF-MS profiling of pharmacologically important chlorogenic acids and associated glycosides in Moringa ovalifolia leaf extracts

Moringa ovalifolia Dinter & A. Berger (Moringaceae) is a succulent-stemmed plant, endemic to the desert and semi-desert areas of central Namibia and southwestern Angola. Just like other species in the Moringaceae family, M. ovalifolia is believed to be rich in health-promoting phytochemicals. However, there are very limited scientific reports on the phytochemical composition and associated biological activities of this plant. Chlorogenic acids (CGAs), major phenolic compounds of Moringa species, have been shown to be effective natural remedies for the management of chronic ailments such as diabetes and cardiovascular diseases. Using a UPLC-ISCID-MS/MS method optimized to mimic the MSn fragmentation of an ion trap-based MS but generating accurate mass data, various isomers of chlorogenic acids and their associated derivatives in the leaves of M. ovalifolia were profiled. M. ovalifolia was shown to contain cis and trans isomers of 3-acyl, 4-acyl and 5-acyl p-coumaroylquinic (pCoQA), caffeoylquinic (CQA) and feruloylquinic acids (FQA) (1-18), a single isomer of 3,5-diCQA (19), 3-CQA-glycoside (20) and two regional isomers of the (3' and 4') glycosides of 4-CQA (21, 22). To the best of our knowledge, this is the first report on the presence of these compounds in M. ovalifolia. The results of the current study confirmed the richness of an underutilized M. ovalifolia as a source of pharmacological relevant metabolites with potential medicinal applications. (C) 2016 Published by Elsevier B.V. on behalf of SAAB.