Dimeric Aporphinoid, Alkaloids, III.

Electrospray Tandem Mass Spectrometry for Structural Characterization of Aporphine-Benzylisoquinoline Alkaloids

“…In the Q1 scan MS data, all the alkaloids revealed apparent protonated molecules (MH + ions) or molecular ion (M +• ) (dimethothalicarpine), together with an intense doublyprotonated molecule (MH 2+ ion) (base peak) except thaliadine, a benzaldehyde-aporphine ether. These data were not observed for those in the EI-MS, CI-MS and FAB-MS. [1][2][3][8][9][10][11][12][13][14][15][16][17][18][19][20] In the electrospray MS/MS, the bond-cleavage at the benzylic ring AB and ring E formed abundant ethereal aporphinebenzylic ions, which are similar fragment patterns to those in the EI-MS data; however, those fragment ions are not observed or show in very low abundances in both CI-MS and FAB-MS. The fragment ion corresponding to ring E, such as fragment ion, dimethoxybenzylic ion, e, is less abundant in the MS/MS data of the investigated alkaloids due to less ionic property and less proton affinities.…”

“…[1][2][3] Aporphine-benzylisoquinoline and bisbenzylisoquinoline alkaloids, two important dimeric classes of isoquinoline alkaloids, exert antihypertensive, antiarrhythmogenic, antianginal, antimicrobial, analgesic, neuromuscular blocking, muscle relaxant and antitumor activities. [1][2][3][4][5][6][7][8][9][10] Thalicarpine, northalicarpine, thalmelatine, adiantifoline and thalirevolutine, five of the ten investigated aporphinebenzylisoquinoline alkaloids exhibit antimicrobial, antitumor and hypotensive activities. [1][2][3][4][5][6][7][8][9][10] Previously, structural elucidation of these natural products has mainly relied on the ultraviolet (UV), infrared (IR), nuclear magnetic reso-nance (NMR), mass spectrometry (MS) [electron ionization (EI), chemical ionization (CI), fast atom bombardment (FAB)] and circular dichroism (CD) spectroscopic data, derivatization, chemical degradation and total synthesis.…”

“…[1][2][3]6,[8][9][10][11][12][13][14][15][16][17][18][19][20] Early EI-MS studies of aporphine-benzylisoquinoline alkaloids displayed low abundances of molecular ions (M +• : < 1% relative abundance) for the secondary and tertiary alkaloids and less fragment ions in high abundance. [1][2][3][6][7][8][9][10][11][12][13][14][15][16][17][18] The CI-MS and FAB-MS spectra showed apparent protonated molecules (MH + ions) for these secondary and tertiary alkaloids; however, there were either no or weak molecular ions for the quaternary alkaloids observed and less fragment ions for structural information of these alkaloids. We have reported previously preliminary results for the structural elucidation of ten aporphine-benzylisoquinoline alkaloids using electrospray MS and tandem (MS/MS) techniques 21 and have also published the in vitro metabolism of thalicarpine, an antitumor, antimicrobial and hypotensive alkaloid, using the rat hepatic S9 incubation.…”

8-, 9-, and 11-Aryloxy Dimeric Aporphines and Their Pharmacological Activities

“…Dimeric aporphines are another class of aporphinoid in which two aporphinoid units are usually connected by either an ether or less frequently a carbon-carbon bond. According to the type and location of this bond, they can be divided into several subgroups [6,[23][24][25]:…”

Thalifaberidine, a Cytotoxic Aporphine-Benzylisoquinoline Alkaloid from Thalictrum faberi

“…indicates no clear correlations with carbons were observed on the irradiation of this proton. bIn order to distinguish the numbering of protons and carbons with letters, the suffixes A and B are used for the gemmal protons of one carbon, and suffixes a and b are used to express some carbons (13)(14)(15).…”