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

Regular paper on-line at: www.actabp.pl The search for polyprenols in dendroflora of Vietnam *+

The occurrence of polyprenols in leaves of over 340 species of dendroflora in natural habitats in the regions of Hanoi and Hue in Vietnam was studied. Plant material was collected in the late autumn (October/November) during the end of a vegetation season. Leaves of about 200 plant species did not contain detectable amounts of polyprenols in contrast to few systematic families, e.g. Moraceae, Euphorbiaceae, where polyprenols were highly abundant and their pattern could be used as a chemotaxonomic criterion. Most often dominating polyprenols were prenol-11 and prenol-12. In several angiosperm species prenol-13 and detectable amounts of prenol-14 were also found. The incidence of prenol-13 and-14 was not restricted to a specific taxonomic group since species exhibiting domination of such longer chain polyprenols belonged to various systematic families. In some plants (e.g. Ceiba pentandra) α-cis polyprenols were accompanied by α-trans counterparts. This report describes several new plant species that may serve as natural sources of long chain polyprenols

Polyisoprenol Specificity in the Campylobacter Jejuni N-linked Glycosylation Pathway

Campylobacter jejuni contains a general N-linked glycosylation pathway in which a heptasaccharide is sequentially assembled onto a polyisoprenyl-diphosphate carrier and subsequently transferred to the asparagine side chain of an acceptor protein. The enzymes in the pathway function at a membrane interface and have in common amphiphilic membrane-bound polyisoprenyl-linked substrates. Herein we examine the potential role of the polyisoprene component of the substrates by investigating the relative substrate efficiencies of polyisoprene-modified analogs in individual steps in the pathway. Chemically defined substrates for PglC, PglJ and PglB are prepared via semisynthetic approaches. The substrates included polyisoprenols of varying length, double bond geometry, and degree of saturation to probe the role of the hydrophobic polyisoprene in substrate specificity. Kinetic analysis reveals that all three enzymes exhibit distinct preferences for the polyisoprenol carrier whereby cis-double bond geometry and α-unsaturation of the native substrate are important features, while the precise polyisoprene length may be less critical. These finding suggest that the polyisoprenol carrier plays a specific role in the function of these enzymes beyond a purely physical role as a membrane anchor. These studies underscore the potential of the C. jejuni N-linked glycosylation pathway as a system for investigating the biochemical and biophysical roles of polyisoprenol carriers common to prokaryotic and eukaryotic glycosylation

Application of supercritical CO2 for extraction of polyisoprenoid alcohols and their esters from plant tissues

In this study, a method of supercritical fluid extraction (SFE) with carbon dioxide of polyisoprenoids from plant photosynthetic tissues is described. SFE was an effective extraction method for short- and medium-chain compounds with even higher yield than that observed for the “classical extraction” method with organic solvents. Moreover, SFE-derived extracts contained lower amounts of impurities (e.g., chlorophylls) than those obtained by extraction of the same tissue with organic solvents. Elevated temperature and extended extraction time of SFE resulted in a higher rate of extraction of long-chain polyisoprenoids. Ethanol cofeeding did not increase the extraction efficiency of polyisoprenoids; instead, it increased the content of impurities in the lipid extract. Optimization of SFE time and temperature gives the opportunity of prefractionation of complex polyisoprenoid mixtures accumulated in plant tissues. Extracts obtained with application of SFE are very stable and free from organic solvents and can further be used directly in experimental diet supplementation or as starting material for preparation of semisynthetic polyisoprenoid derivatives, e.g., polyisoprenoid phosphates

Double Bond Stereochemistry Influences the Susceptibility of Short‑Chain Isoprenoids and Polyprenols to Decomposition by Thermo‑Oxidation

Alcohols are common constituents of living cells. They are usually assigned a role in the adaptation of the cell to environmental stimuli, and this process might give rise to their oxidation by reactive oxygen species. Moreover, cellular isoprenoids may also undergo various chemical modifications resulting from the physicochemical treatment of the tissues, e.g., heating during food processing. Susceptibility of isoprenoid alcohols to heat treatment has not been studied in detail so far. In this study, isoprenoid alcohols differing in the number of isoprene units and geometry of the double bonds, β-citronellol, geraniol, nerol, farnesol, solanesol and Pren-9, were subjected to thermo-oxidation at 80 °C. Thermo-oxidation resulted in the decomposition of the tested short-chain isoprenoids as well as medium-chain polyprenols with simultaneous formation of oxidized derivatives, such as hydroperoxides, monoepoxides,diepoxides and aldehydes, and possible formation of oligomeric derivatives. Oxidation products were monitored by GC-FID, GC-MS, ESI-MS and spectrophotometric methods. Interestingly, nerol, a short-chain isoprenoid with a double bond in the cis (Z) configuration, was more oxidatively stable than its trans (E) isomer, geraniol. However, the opposite effect was observed for medium-chain polyprenols, since Pren-9 (di-trans-poly-cis-prenol) was more susceptible to thermo-oxidation than its all-trans isomer, solanesol. Taken together, these results experimentally confirm that both short- and long-chain polyisoprenoid alcohols are prone to thermo-oxidation