ABSTRACT
Five new quinolizidine alkaloids were isolated from the leaves of Cylicomorpha solmstii (Urb.) Urb. (Caricaceae) and named cylicomorphins A-E (1-5). They all are ester derivatives of the same basic quinolizidine skeleton bearing hydroxy, methyl, and ethanoic acid substituents. Their structures were mainly established by NMR spectroscopy, and the absolute configuration is proposed on the basis of VCD data and Mosher ester derivatization. Compound 5 displayed cytotoxicity in the 10 µM range against an HCT-116 cell line.
Subject(s)
Alkaloids/pharmacology , Antineoplastic Agents, Phytogenic/pharmacology , Caricaceae/chemistry , Quinolizidines/pharmacology , Alkaloids/isolation & purification , Antineoplastic Agents, Phytogenic/isolation & purification , Cameroon , HCT116 Cells , Humans , Molecular Structure , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , Plant Leaves/chemistry , Quinolizidines/isolation & purificationABSTRACT
Four alkaloids named hosieines A-D were isolated from the root and stem of Ormosia hosiei. Their flat structures were established by mass spectrometry and by a combination of NMR experiments. These molecules probably share a common biosynthetic origin with the lupin alkaloids but they differ in the formation of the last ring, being here part of a rare 2-azabicyclo[3.2.1]octane system. Their absolute configuration was determined by X-ray crystallography using CuKα radiation. As has been described for cytisine, they display a remarkable affinity towards neuronal nicotinic acetylcholine α4ß2 receptor.
Subject(s)
Alkaloids/isolation & purification , Fabaceae/chemistry , Receptors, Nicotinic/drug effects , Alkaloids/chemistry , Alkaloids/pharmacology , Azocines/chemistry , Azocines/isolation & purification , Azocines/pharmacology , Crystallography, X-Ray , Molecular Conformation , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Roots/chemistry , Plant Stems/chemistry , Quinolizines/chemistry , Quinolizines/isolation & purification , Quinolizines/pharmacologyABSTRACT
Six protoflavonoids, including two new compounds, were isolated during a large scale screening of fern extracts for original interaction with mitosis. The new compounds isolated from PHEGOPTERIS decursive-pinnata and EQUISETUM fluviatile were 2',3'-dihydroprotogenkwanone (1) and 2',3'-dihydro-2'-hydroxyprotoapigenone (2). Known compounds were: protoapigenone, protogenkwanone, protoapigenin, and 4'- O- ß-D-glucopyranosyl protoapigenin. They showed a cytotoxic activity against HeLa cells at a micromolar level. IC50 values were 2 µM for compound 1 > 10 µM for compound 2, and respectively 2.4, 0.6, > 10 µM for the known compounds. Their cytotoxic effects were associated with phenotypic changes never observed before and characterized by the loss of centrosomal γ-tubulin labelling in both mitotic and interphasic cells.
