The combination of NMR, MS, and CD data permitted the structural elucidation including the absolute configuration of the known alkaloids and unknown components in the extract matrix solution of Nandina domestica without isolation and sample purification prior to the coupling experiments. Unstable natural stereoisomers were identified by LC-NMR and LC-MS. Five known alkaloids, (S)-isoboldine, (S)-domesticine, (S)-nantenine, sinoacutine, and menispermine, were identified from N. domestica. O-Methylpallidine and (E, E)-, (E, Z)-, and (Z, Z)-terrestribisamide were also characterized for the first time from this plant. Known jatrorrhizine, palmatine, and berberine and unknown (R)-carnegine and (E, E)-, (E, Z)-, and (Z, Z)-terrestribisamide were identified in the callus of N. domestica.

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A metabolic pathway of 2,3,10,11-oxygenated tetrahydroprotoberberines having the OH group on ring D was demonstrated. Metabolism of (13)C- or D(2)-labeled precursors was studied in cell cultures of Macleaya, Corydalis, and Nandina species. The structures of alkaloid metabolites obtained from feeding experiments were determined by application of combined LC-NMR, LC-MS/MS, and LC-CD techniques. (S)-Tetrahydropseudoprotoberberine (5) was stereospecifically O-methylated to the S-isomer (12) in cell cultures of three plant species. This S-isomer was further N-methylated to the (S)-alpha-N-methyl salt (15), which was oxidized to produce the pseudoprotopine-type alkaloid (10) in cell cultures of Macleaya and Corydalis species. These transformations were the same as those of 2,3,9,10-oxygenated protoberberines. The tetrahydropseudoprotoberberines (5, 6, and 12) were dehydrogenated to pseudoprotoberberines (13, 16, and 14), respectively. Both the R- and S-enantiomers of 5 were dehydrogenated in Macleaya cordata different from the case of 2,3,9,10-oxygenated protoberberines. Precursor 7, with OH groups at C-10 and C-11, was O-methylated at C-10 in M. cordata and C. ochotensis var. raddeana, which was distinct from O-methylation in N. domestica, in which 7 was O-methylated at both C-11 and C-10. Stereoselective O-demethylation [(S)-5 to (S)-18] occurred in N. domestica.