New synthesis of spirocycles by utilizing in situ forming hypervalent iodine species

A very effective spirocyclization procedure for installing nucleophiles (Nu = N(3), NO(2), SCN, SO(2)Tol, and halogens) via iodonium(III) salts has been developed using the combination of iodoarene and mCPBA. The high-yielding syntheses of the cyclohexadienone-type spirocyclic compounds 2 having varied functionalities in the skeletons have been achieved from the aryl alkynes 1 with the optimized bis(iodoarene) 3h.     

Derivatization reagents in liquid chromatography/electrospray ionization tandem mass spectrometry

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is often used to enhance the detection sensitivity. Derivatization improves the chromatographic separation, and enhances the mass spectrometric ionization efficiency and MS/MS detectability. In this review, an overview of the derivatization reagents which have been applied to LC/ESI-MS/MS is presented, focusing on the applications to low molecular weight compounds.     

Triterpene Saponins from Four Species of the Polygalaceae Family

Twelve triterpene saponins were isolated by successive MPLC over silica gel from four species of Polygalaceae: From Polygala ruwenzoriensis, five new saponins 1 – 5 of which 1 – 4 as two pairs of (E)/(Z)‐isomers, together with the four known compounds tenuifoline, (E)‐ and (Z)‐senegasaponin b, (E)‐ and (Z)‐senegin II, and polygalasaponin XXVIII, from the genus Carpolobia, one new saponin 6 from C. alba and the known arilloside ( 11 ) from C. lutea, and another new triterpene glycoside 7 from Polygala arenaria. Their structures were established mainly by 600‐MHz 2D‐NMR techniques (¹H,¹H‐COSY, TOCSY, NOESY, HSQC, HMBC) as 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1 → 4)‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐4‐methoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1 → 4)‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐[O‐β‐D ‐galactopyranosyl‐(1 → 4)‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐β‐D ‐fucopyranosyl] ester ( 5 ), 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1 → 3)‐O‐[β‐D ‐galactopyranosyl‐(1 → 4)]‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐O‐[β‐D ‐apiofuranosyl‐(1 → 3)]‐4‐O‐acetyl‐β‐D ‐fucopyranosyl} ester ( 6 ), and 3‐O‐(β‐D ‐glucopyranosyl)presenegenin 28‐{O‐β‐D ‐galactopyranosyl‐(1 → 4)‐O‐[β‐D ‐glucopyranosyl‐(1 → 3)]‐O‐β‐D ‐xylopyranosyl‐(1 → 4)‐O‐α‐L ‐rhamnopyranosyl‐(1 → 2)‐β‐D ‐fucopyranosyl} ester ( 7 ) (presenegenin = (2β,3β,4α)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid).     

Effects of ultrasound on apoptosis induced by anti-CD20 antibody in CD20-positive B lymphoma cells

AIM: The present study was conducted to examine the thermal and non-thermal effects of ultrasound on apoptosis induced by anti-CD20 monoclonal antibody (rituximab). MATERIALS AND METHODS: SU-DHL-4 cells, a CD20-positive cell line derived from B cell lymphomas with a BCL2 gene rearrangement, were exposed to continuous 1 MHz ultrasound for therapeutic use under an air- or CO(2)-saturated condition to control cavitation. Early apoptosis (EA) and secondary necrosis (SN) were examined by flow cytometry. Cavitation was determined by detecting the hydroxyl radicals derived from pyrolysis of water molecules using electron paramagnetic resonance-spin trapping. To assess thermal effects, cells were treated in a temperature-controlled water bath. RESULTS: There was a significant additive increase in EA and EA+SN observed in cells treated with rituximab combined with heat at 42 degrees C or non-thermal ultrasound at 0.5 W/cm(2) under an air-saturated condition, where heat or ultrasound induced some cell death. A significant synergistic increase in EA and EA+SN was observed in cells treated with rituximab and ultrasound at 2.5 W/cm(2) under CO(2)-saturated conditions, where inertial cavitations were completely suppressed. No enhancement was observed at a temperature less than 40 degrees C or ultrasound at 0.5 W/cm(2) under CO(2)-saturated conditions. CONCLUSION: These results suggest that the immuno-therapeutic application of ultrasound at relatively high-intensities combined with rituximab thus produces synergistic effects under conditions where the non-thermal and non-cavitational effects are predominant.     

An automated fluorescence protein sequencer using 7-methylthio-4-(2,1,3-benzoxadiazolyl) isothiocyanate (MTBD-NCS) as an Edman reagent

An automated fluorescence protein sequencer using 7-methylthio-5-(2,1,3-benzoxadiazolyl) isithiocyanate (MTBD-NCS), a fluorescent Edman reagent, is developed by the modification of a commercial protein sequencer. The generated MTBD-thiohydantoin amino acids fluoresced strongly, whereas the by-products such as MTBD-thiocarbamoyl amino acids and MTBD-carbamoly amino acids did not fluoresce. A few interfering peaks were observed in the chromatogram and amino acid sequence was easily determined. The coupling and cyclization/cleavage reaction conditions and extraction conditions of generated MTBD-thiazolinone amino acids were optimized using an autonalyzer. Finally, the sequence of a synthetic peptide (25 pmol), leucine-enkephalin-Thr-amide, was determined and up to six residues were successively analyzed.     

Isolation and structure of a GD3-Type ganglioside molecular species possessing neuritogenic activity from the starfish Luidia maculata

A GD3-type ganglioside molecular species, LMG-4 (1), has been obtained from the polar lipid fraction of the chloroform/methanol extract of the starfish Luidia maculata. The structure of this ganglioside has been determined on the basis of chemical and spectroscopic evidence to be 1-O-[(N-acetyl-alpha-D-neuraminosyl)-(2-->8)-(N-acetyl-alpha-D-neuraminosyl)-(2-->3)-beta-D-galactopyranosyl-(1-->4)-beta-D-glucopyranosyl]-ceramide. The ceramide moiety was composed of heterogeneous 2-hydroxy fatty acid and phytosphingosine units. This is the first report on the isolation and structure elucidation of GD3-type ganglioside from echinoderms. Moreover, 1 exhibited neuritogenic activity toward the rat pheochromocytoma PC12 cells in the presence of nerve growth factor.     

Constituents of Crinoidea. 3. Isolation and structure of a glycosyl inositolphosphoceramide-type ganglioside with neuritogenic activity from the feather star Comanthus japonica

A glycosyl inositolphosphoceramide-type ganglioside, CJP4, was obtained from the polar lipid fraction of the chloroform/methanol extract of the feather star Comanthus japonica. The structure of this ganglioside has been determined on the basis of chemical and spectroscopic evidence to be 9-O-methyl-(N-glycolyl-alpha-D-neuraminosyl)-(2-->11)-9-O-methyl-(N-glycolyl-alpha-D-neuraminosyl)-(2-->11)-9-O-methyl-(N-glycolyl-alpha-D-neuraminosyl)-(2-->3)-inositolphosphoceramide, which contains C(16)-sphingosine and C(22:0)-, C(24:0)-fatty acid. This is the first report on the isolation and structural elucidation of a trisialo-glycosyl inositolphosphoceramide-type ganglioside. Moreover, CJP4 exhibited neuritogenic activity toward the rat pheochromocytoma PC12 cells in the presence of nerve growth factor.     

Comparison of the migration behavior of nanoparticles based on polyethylene glycol and silica using micellar electrokinetic chromatography

Nanoparticles, spherical particles with diameters less than 100 nm, are promising theranostic devices for noninvasive diagnosis and therapy. In this study, nanoparticles composed of polyethylene glycol and silica were prepared, and their migration behavior was examined using capillary electrophoresis. The effects of the sodium dodecyl sulfate concentration in the electrolyte, the nanoparticle size, and the encapsulated molecule on the migration were examined. The addition of sodium dodecyl sulfate into the electrolyte had a significant effect on the electrophoretic mobility of polyethylene glycol nanoparticles, but a small effect on that of silica nanoparticles. As for the size effect, the mobility became a little faster for smaller nanoparticle sizes for both polyethylene glycol and silica nanoparticles. The encapsulated molecule affected the mobility of the nanoparticles through interactions between the encapsulated molecules and sodium dodecyl sulfate. We propose that the large effect of sodium dodecyl sulfate on the migration of the polyethylene glycol nanoparticles was due to the large spaces within the nanoparticles. These results indicate that nanoparticle migration is mainly determined by the nanoparticle components.