Sphingosine and clavaminol H derivatives bearing fluorinated chains and their cytotoxic activity

Penta-deuterium-labeled 4E, 8Z-sphingadienine for rapid analysis in sphingolipidomics study

The use of deuterium-incorporated bioactive compounds is an efficient method for tracing their metabolic fate and for quantitative analysis by mass spectrometry without complicated HPLC separation even if their amounts are extremely small. Plant sphingolipids and their metabolites, which have C4, 8-olefins on a common backbone as a sphingoid base, show unique and fascinating bioactivities compared to those of sphingolipids in mammals. However, the functional and metabolic mechanisms of exogenous plant sphingolipids have not been elucidated due to the difficulty in distinguishing exogenous sphingolipids from endogenous sphingolipids having the same polarity and same molecular weight by mass spectrometric analysis. Their roles might be elucidated by the use of deuterated probes with original biological and physicochemical properties. In this study, we designed (2S,3R,4E,8Z)-2-aminooctadeca-4,8-diene-17,17,18,18,18-d₅-1,3-diol (penta-deuterium-labeled 4E, 8Z-sphingadienine) as a tracer for exogenous metabolic studies. In addition, the sphingadienine was confirmed to be metabolized in HEK293 cells and showed distinct peaks in mass spectrometric analysis.

Azidosphinganine enables metabolic labeling and detection of sphingolipid de novo synthesis

Here were report the combination of biocompatible click chemistry of ω-azidosphinganine with fluorescence microscopy and mass spectrometry as a powerful tool to elaborate the sphingolipid metabolism. The azide probe was efficiently synthesized over 13 steps starting from l-serine in an overall yield of 20% and was used for live-cell fluorescence imaging of the endoplasmic reticulum in living cells by bioorthogonal click reaction with a DBCO-labeled fluorophore revealing that the incorporated analogue is mainly localized in the endoplasmic membrane like the endogenous species. A LC-MS(/MS)-based microsomal in vitro assay confirmed that ω-azidosphinganine mimics the natural species enabling the identification and analysis of metabolic breakdown products of sphinganine as a key starting intermediate in the complex sphingolipid biosynthetic pathways. Furthermore, the sphinganine-fluorophore conjugate after click reaction was enzymatically tolerated to form its dihydroceramide and ceramide metabolites. Thus, ω-azidosphinganine represents a useful biofunctional tool for metabolic investigations both by in vivo fluorescence imaging of the sphingolipid subcellular localization in the ER and by in vitro high-resolution mass spectrometry analysis. This should reveal novel insights of the molecular mechanisms sphingolipids and their processing enzymes have e.g. in infection.

Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

Cross-metathesis of α- and β-vinyl C-deoxyribosides and α-vinyl C-galactoside with various terminal alkenes under different conditions was studied. The cross-metathesis of the former proceeded with good yields of the corresponding products in ClCH2CH2Cl the latter required the presence of CuI in CH2Cl2 to achieve good yields of the products. A simple method for the preparation of α- and β-vinyl C-deoxyribosides was also developed. In addition, feasibility of deprotection and further transformations were briefly explored.

Medicinal applications of perfluoroalkylated chain-containing compounds

Compounds with polyfluorinated molecular fragments possess unique properties associated with the presence of a large number of fluorine atoms that affect lipophilicity and conformational rigidity of the parent molecule along with other effects. The aim of this review is to provide an overview of synthesized compounds possessing perfluoroalkylated or polyfluorinated chains that have been tested for bioactivity or as potential drug candidates for the treatment of various diseases. As far as the length of the perfluoroalkylated chain is concerned the focus is centered on the compound bearing perfluoroethyl or tetrafluoroethyl as well as longer chains. The perfluoroalkylated compounds discussed are classified according to their biological activity.