Chemistry of Natural Compounds

Phytochemical investigation of the 95% EtOH extract of red yeast rice fermented with the fungus Monascus ruber led to the isolation and structural elucidation of one new azaphilone derivative, monascuspurone (1). The structure was defined on the basis of UV, IR, 1D and 2D NMR (1H–1H COSY, DEPT, HSQC, HMBC), as well as HR-ESI-MS analyses, and comparison of the spectroscopic data with those reported for structurally related compounds.

The CD spectra of 8-bromo-AMP, 8-bromo-dAMP, 8-bromo-GMP, and 8-bromo-dGMP in acid, neutral, and alkaline media and, in some cases, in methanol have been obtained. In the 200–300 nm region three Cotton effects have been recorded which correspond to π-π* in the B2u, B1u, and E1ua bands (280–265, 240–250, and 200–220 nm, respectively). The CD spectra obtained differ from the spectra known in the literature for unbrominated compounds of this class. It has been shown that in ribonucleotides the syn conformation is stabilized by the formation of an intramolecular hydrogen bond with the participation of the ribose 2′-hydroxyl and the N3 atom of the purine base. The 5′-phosphate group in the molecule of a purine nucloside of the syn type changes the CD profile, particularly in the short-wave region of the spectrum, as compared with the CD spectra of the unbrominated analogs given in the literature.

An excess of periodic acid was reacted with the diterpenoid alkaloid demethyleneldelidine (1) to produce a γ-lactone (2) in which the carbonyl at the C6-position was selectively reduced by an excess of NaBH4. The conformation of the rings, configuration of asymmetric and spiro centers, and the nature of intramolecular H-bonds in the diterpenoid alkaloid demethyleneldelidine and its reduction product 3 were analyzed by an x-ray structure analysis. The spiro center at C10 in 3 had the S-configuration. The other asymmetric centers retained the absolute configuration characteristic of alkaloids with the lycoctonine carbon skeleton. The pharmacological properties did not change significantly despite the large difference in the carbon skeletons of γ-lactone 3 and starting 1.

Organic volatiles obtained by microdistillation from five common spices (Coriandrum sativum L., Foeniculum vulgare Miller, Piper nigrum L., Anethum graveolens L., Pimpinella anisum L.) using an Eppendorf Micro-Distiller were analyzed by GC/MS. The results are presented in a comparative manner with conventional water distillation.