No abstract

Lycorine (1), one of the main alkaloids of the Amaryllidaceae family, was found to be responsible for the pronounced antiviral activity of the crude extracts from the roots and leaves of Clivia miniata Regel. It was shown that the inhibitory activity of lycorine on the cytopathogenic effect caused by a DNA and several RNA viruses on VERO cells was not virucidal. Poliomyelitis virus inhibition occurred at lycorine concentrations as low as 1 microgram/ml, whereas concentrations exceeding 25 micrograms/ml were found to be cytotoxic. Clivimine (2), clivonine (3) and cliviamartine (4) were also isolated and characterized, but these alkaloids exhibited no antiviral properties.

No abstract

In order to obtain detection limits low enough for the analysis of nucleoside material in biological samples, a direct liquid introduction (liquid chromatographic/mass spectrometric DLI) system was upgraded by inserting a self-built desolvation chamber between the DLI probe and the ion source and by switching to microbore high-performance liquid chromatography (HPLC) on a C-18 column. The system was evaluated for the analysis of pure nucleoside and 2'-deoxynucleoside compounds in CH3OH + H2O (80/20) and for the analysis of nucleoside mixtures which were separated using 0.01 M ammonium formate + methanol (97:3) as eluant. The detection of structurally important fragment ions in the lower mass region which could not be observed before and an enhanced sensitivity are considered to be the main improvements. In combination with an appropriate clean-up procedure the system was evaluated for the DLI liquid chromatographic/mass spectrometric analysis of some nucleosides present in a human urine sample. Pseudouridine and 5,6-dihydrouridine were detected and identified.

No abstract

The substance known as "isohumulone" is in fact a mixture of four components. They were separated by C.C.D. According to a new nomenclature based mainly on the chemically related humulinic acids A,B, C etc. series they are the stereoisomers isohumulone A and B (IV and V) and alloisohumulone A and B (VI and VII).From the reaction with iodine it was deduced earlier (1) that the isomerization mixture of humulone (I) contained not only isomer 11, but also isomer 111. Counter current distribution (C.C.D.) with a large number of transfers has now revealed that both isomer I1 and I11 are still a mixture of two components each. The proton magnetic resonance (PMR) spectra of these compounds prove that they are the stereoisomers IV, V, VI and VII and are therefore structurally related to the humulinic acids A and B (29394).It is suggested to use the suffix A for substances in this field having the alkenyl chain and the hydroxyl group in trans position. The compound with a cis configuration of these substituents receives then the B suffix to its name. Substances IV and V are then isohumulone A and isohumulone B respectively.Earlier meanings for the A, B etc. suffixes should be dropped. Substances VI and VII will be called alloisohumulones and are respectively again the A and B compound.Alloisohumulones are formed by isomerization of humulone in boiling phosphate buffer adjusted to pH 9.0 at 250, and also by the iso-(*) This is the 44th paper on hop constituents from our laboratory. (1964).

No abstract

Promising results were obtained by chemical ionization desorption mass spectrometry for a series of original pyridinium nucleoside salts, together with some purine and pyrimidine nucleo(t)sides. They were recorded using ammonia as reagent gas and tungsten wires. Principal ions correspond to protonated or cationized ([NH,I+) forms of the molecular ion or the free base depending upon the compound under investigation.