0000000000336593
AUTHOR
Katja Maksimenka
showing 3 related works from this author
Joziknipholones A and B: The First Dimeric Phenylanthraquinones, from the Roots ofBulbine frutescens
2007
From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P-co…
The first sorbicillinoid alkaloids, the antileukemic sorbicillactones A and B, from a sponge-derived Penicillium chrysogenum strain
2005
The saltwater culture of a Penicillium chrysogenum strain isolated from the Mediterranean sponge Ircinia fasciculata yielded three new sorbicillin-derived compounds (1-3), whose structures were elucidated mainly by 2D NMR and mass spectrometry. Among them, sorbicillactones A (1) and B (2) are the first sorbicillinoid natural products that contain nitrogen. Compound 1 is anti-HIV active and it exhibits a strong cytotoxic activity against L5178y leukemic cells, combined with a relatively low toxicity to cervical carcinoma HeLa S3 cells and pheochromocytoma PC 12 cells. The absolute configurations of I and 2 were elucidated by quantum chemical calculation of circular dichroism (CD) spectra. An…
Gephyromycin, the first bridged angucyclinone, from Streptomyces griseus strain NTK 14
2005
The new, highly oxygenated angucyclinone gephyromycin was isolated from an extract of a Streptomyces griseus strain. Its unprecedented ether-bridged structure was elucidated by NMR methods and substantiated by single crystal X-ray analysis. The absolute configuration was evidenced by quantum chemical CD calculations. Gephyromycin exhibits glutaminergic activity towards neuronal cells. Furthermore, the known compounds fridamycin E and dehydrorabelomycin were identified.