montanine and pancracine

Plants of the Amaryllidaceae family are promising therapeutic tools for human diseases and have been used as alternative medicines. The specific secondary metabolites of this plant family, called Amaryllidaceae alkaloids (AA), have attracted considerable attention due to their interesting pharmacological activities. One of them, galantamine, is already used in the therapy of Alzheimer's disease as a long acting, selective, reversible inhibitor of acetylcholinesterase. One group of AA is the montanine-type, such as montanine, pancracine and others, which share a 5,11-methanomorphanthridine core. So far, only 14 montanine-type alkaloids have been isolated. Compared with other structural-types of AA, montanine-type alkaloids are predominantly present in plants in low concentrations, but some of them display promising biological properties, especially in vitro cytotoxic activity against different cancerous cell lines. The present review aims to summarize comprehensively the research that has been published on the Amaryllidaceae alkaloids of montanine-type.

Topics: Amaryllidaceae; Amaryllidaceae Alkaloids; Antineoplastic Agents, Phytogenic; Antiprotozoal Agents; Cell Line, Tumor; Cholinesterase Inhibitors; Galantamine; Heterocyclic Compounds, 4 or More Rings; Humans; Inhibitory Concentration 50; Isoquinolines; Nootropic Agents; Phenanthridines; Plant Extracts; Secondary Metabolism

An unexpected rearrangement of haemanthamine-type alkaloids in the presence of halogenating agents has been found. Rearranged compounds present the 5,11-methanomorphantridine framework characteristic of montanine-type alkaloids. These compounds are difficult to obtain because of their scarcity in natural sources and because the synthetic approaches developed so far require numerous steps. Vibrational circular dichroism (VCD) spectroscopy was used to determine the absolute configuration of one of the rearranged compounds. Several rearranged alkaloids showed antimalarial activity.

Topics: Alkaloids; Amaryllidaceae Alkaloids; Animals; Antimalarials; Circular Dichroism; Heterocyclic Compounds, 4 or More Rings; Isomerism; Isoquinolines; Models, Molecular; Molecular Structure; Phenanthridines; Plasmodium falciparum