Chromatographic profiling and identification of two new iridoid- indole alkaloids by UPLC-MS and HPLC-SPE-NMR analysis of an antimalarial extract from Nauclea pobeguinii

The total 80% EtOH extract of stem bark of Nauclea pobeguinii (Rubiaceae), which is active against uncomplicated falciparum malaria as shown in previous clinical studies, was analysed by means of UPLC-MS and HPLC-SPE-NMR. Apart from the main constituent, strictosamide, a series of minor constituents was identified, including two new iridoid-indole alkaloids, i.e. naucleidinic acid and 19-O-methyl-3,14-dihydroangustoline, together with 8 known iridoid-indole alkaloids, i.e. naucleidinal, magniflorine, naucleofficine D, two diastereoisomers of 3,14-dihydroangustoline, strictosidine, desoxycordifoline, 3 alpha,5 alpha-tetrahydrodeoxycordifoline lactam, and a phenol glycoside 3,4,5-trimethoxyphenol beta-D-apiofuranosyl-(1-6)-beta-D-glucopyranoside (kelampayoside A). (C) 2012 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.