Ancistrocyclinones A and B, unprecedented pentacyclic N,C-coupled naphthylisoquinoline alkaloids, from the Chinese liana Ancistrocladus tectorius

Journal article

Two unique pentacyclic N,C-coupled naphthylisoquinolines, the ancistrocyclinones A (5) and B (6), were discovered in the Chinese liana Ancistrocladus tectorius. Furthermore, six known, likewise N,C-coupled alkaloids, viz., ancistrocladinium A (7a) and its mono- and bisphenolic analogs 8a and 9a were isolated, along with their atropo-diastereomers 7b, 8b, and 9b. The stereostructures of 5 and 6 were determined by HRESIMS, 1D and 2D NMR, oxidative degradation, and ECD calculations. The pentacyclic ancistrocyclinones A (5) and B (6) are structurally similar to berberine alkaloids - yet arising from a most different biosynthetic pathway: they are apparently formed by N,C-coupling of their polyketide-derived molecular halves, followed by oxidative cyclo-condensation. Biomimetic conversion of the co-occurring 4'-O-demethylancistrocladinium A (8a) to ancistrocyclinone A (5) via a quinoid intermediate supported the postulated pathway. Ancistrocyclinone A (5) was found to significantly inhibit the viability of drug-sensitive human leukemia (CCRF-CEM) and multidrug-resistant tumor cells (CEM/ADR5000) with comparable efficacies.

Authors: Seupel, R; Hemberger, Y; Feineis, D; Xu, M; Seo, E

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society of Chemistry
• Journal: Organic and Biomolecular Chemistry
• Volume: 16
• Issue: 9
• Pages: 1581-1590
• Publication date: 2018-02-05
• Acceptance date: 2018-02-05
• DOI: 10.1039/c7ob03092d
• EISSN: 1477-0539
• ISSN: 1477-0520
• Pmid: 29443340
• Language: English