NMR and gas chromatography studies of lyophilized human brain tumors.

1H HR MAS (high resolution magic angle spinning) NMR is a promising tool in the in vitro characterisation of brain tumors. Brain tissue samples were collected from patients with intracranial tumors during surgery, frozen and lyophilized. The analysis of solid samples was performed by high-speed rotation (33 kHz) H MAS NMR. The most intense resonances arise from lipids (methylene mid-chain and methyl carbons of fatty acids). 1H MAS spectra obtained from the same histological type of brain tumors are similar; spectra of glioblastomas were different from those of meningiomas. 1H and 13C NMR solution spectra of lipid extracts confirmed the presence of aliphatic chains fatty acids and cholesterol as major constituents. Biochemical information on liberated fatty acid composition was obtained by gas-chromatography (GC). The glioma content of the linoleic acid (18:2n6) was found to be greater, whereas the level of docosahexaenoic acid (22:6n3) was significantly reduced.

Prenyl sulfates as alkylating reagents for mercapto amino acids.

A new methodology for prenylation of thiol compounds has been developed. The approach is based on the use of prenyl sulfates as new reagents for S-prenylation of benzenethiol and cysteamine in aqueous systems. The C(10)-prenols geraniol and nerol that differ in the configuration (E or Z, correspondingly) of the alpha-isoprene unit were efficiently O-sulfated in the presence of a pyridine-SO(3') complex. The obtained geranyl and neryl sulfates were tested as alkylating agents. These compounds were chosen to reveal the influence of the alpha-isoprene unit configuration on their alkylation (prenylation) ability. S-Geranyl cysteine was prepared to demonstrate the applicability of this method for prenylation of peptides containing mercapto amino acids.

New cationic polyprenyl derivative proposed as a lipofecting agent.

Cationic linear poly-cis-isoprenoid prepared from natural plant polyprenol in a mixture with dioleyl phosphatidylethanolamine was found to be an effective lipofection agent for eukaryotic cells. The transfecting activity is related to the poly-cis structure of the polyprenyl chain.

The occurrence of polyprenols in seeds and leaves of woody plants.

The contents of the heterogenous group of polyisoprenoids was found about two orders of magnitude lower in seeds than the amount of polyprenols and/or their carboxylic esters accumulated during vegetation season in leaves. In contrast to leaves, no seeds were found containing more than 0.5 mg of these lipids per gram of dry tissue. Almost 50% had less than 0.01 mg/g - the amount which is the limit of detection by the procedure used in this work. In gymnosperms (10 representatives of Cupressaceae, Pinaceae and Taxaceae) the polyprenol spectra in seeds and in needles were similar. In angiosperms (25 representatives of 13 botanical families) the polyisoprenoid mixture in seeds resembled the minor, additional subfamily found in leaves.