Mbandakamine-Type Naphthylisoquinoline Dimers and Related Alkaloids from the Central African Liana Ancistrocladus ealaensis with Antiparasitic and Antileukemic Activities

J Nat Prod. 2018 Apr 27;81(4):918-933. doi: 10.1021/acs.jnatprod.7b01041. Epub 2018 Mar 21.

Abstract

Four new dimeric naphthylisoquinoline alkaloids, michellamine A5 (2) and mbandakamines C-E (4-6), were isolated from the Congolese plant Ancistrocladus ealaensis, along with the known dimer mbandakamine A (3). They represent constitutionally unsymmetric dimers, each consisting of two 5,8'-coupled naphthylisoquinoline monomers. While the molecular halves of michellamine A5 (2) are linked via C-6' of both of the naphthalene moieties, i.e., via the least-hindered positions, so that the central biaryl axis is configurationally unstable and not an additional element of chirality, the mbandakamines 3-6 possess three consecutive stereogenic axes. Their monomeric units are linked through an unprecedented 6',1″-coupling in the binaphthalene core, leading to a high steric load, since the central axis is located in one of the peri-positions, neighboring one of the outer axes. In addition, four new 5,8'-coupled monomeric naphthylisoquinolines, viz., ancistroealaines C-F (7-10), were identified, along with four "naphthalene-devoid" tetra- and dihydroisoquinolines, named ealaines A-D (11-14). The new mbandakamines C (4) and D (5) showed pronounced activities against the malaria parasite Plasmodium falciparum, and they were likewise found to display strong cytotoxic activities against human leukemia (CCRF-CEM) and multi-drug-resistant tumor cells (CEM/ADR5000).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa, Central
  • Alkaloids / pharmacology*
  • Antimalarials / pharmacology
  • Antineoplastic Agents, Phytogenic
  • Antiparasitic Agents / pharmacology*
  • Caryophyllales / chemistry*
  • Cell Line, Tumor
  • Humans
  • Isoquinolines / pharmacology*
  • Naphthalenes / pharmacology*
  • Plasmodium falciparum / drug effects
  • Quinolines / pharmacology*

Substances

  • Alkaloids
  • Antimalarials
  • Antineoplastic Agents, Phytogenic
  • Antiparasitic Agents
  • Isoquinolines
  • Naphthalenes
  • Quinolines
  • michellamine A
  • quinoline