Fragmentation patterns of newly isolated cassane butenolide diterpenes and differentiation of stereoisomer by tandem mass spectrometry

Different stereoisomers of active molecules often cause different physiological responses and hence pose a challenge for their identification. This study involves perceptive fragmentation behavior of newly isolated cassane butenolides, caesalpinolide A [1] and caesalpinolide B [2] (epimeric at the hemiketal position) by tandem MS. The electrospray ionization-mass spectrometry (ESI-MS)/collision-induced dissociation (CID; ESI-MS(2) and ESI-IT-MS(n)) were investigated. The effect of orientations of hemiketal hydroxyl at C-12 was clearly observed in the mass spectrum. Tandem mass spectra of 1, 1(A) or 2, 2(A) show stereospecific fragmentation resulting in significant abundance dissimilarity of [MH - H(2)O](+) as well as differences in fragmentation pathway. Both of these pathways seem to be influenced by the stereochemistry of the molecule. The differentiation can be clearly visualized from the [M + H - H(2)O](+)/[M + H](+) ratio of the two isomers where beta-isomer 2 was found to be five times higher than that of alpha-isomer 1 in full scan liquid chromatography-electrospray ionization mass spectrometry(LC-ESI-MS). In high-energy CID, the mass fingerprint of 1, 2, 1(A), and 2(A) was found to be different from one another.     

Delivery of Benzoporphyrin Derivative, a Photosensitizer, into Atherosclerotic Plaque of Watanabe Heritable Hyperlipidemic Rabbits and Balloon-Injured New Zealand Rabbits

Abstract— In this study we compared the plasma distribution and arterial accumulation of a photosensitizer, benzoporphyrin derivative (BPD), in two models of atherosclerosis: the spontaneous lesions of the Watanabe heritable hyperlipidemic (WHHL) rabbit and induced lesions of the balloon-injured, cholesterol-fed New Zealand white (NZW) rabbit. Selective uptake and retention of a photosensitizer by the abnormal portion of a vessel is a necessity in order for photodynamic therapy to become a successful modality for inhibition of intimal hyperplasia, selective removal of atherosclerotic tissue or imaging of diseased arteries. Liposome-based formulations were compared to freshly isolated native low density lipoprotein (LDL) and acetylated-LDL (Ac-LDL) as delivery vehicles for BPD. Plasma distribution of the photosensitizer was analyzed by KBr density gradient ultracentrifuga-tion. Although the delivery vehicle influenced plasma distribution immediately postinjection, BPD subsequently partitioned according to the plasma concentration of the lipoproteins. Photosensitizer level in plaque and normal artery specimens was determined by ethyl acetate extraction and spectrofluorometric measurement. The measurement of BPD in normal and atherosclerotic arterial tissue demonstrated a selective accumulation in atherosclerotic tissue. Preassociation with LDL and Ac-LDL enhanced accumulation of BPD in atherosclerotic tissue when compared with normal artery (mean ratios of 2.8 and 4.1 were achieved, respectively). These results indicate that the preferential uptake of BPD by atherosclerotic plaque can be enhanced by preassociation with plasma lipoproteins, suggesting that light activation could lead to a highly selective destruction of diseased vascular tissue.     

Polarographie von Indium(III) in Alkali-und Erdalkalinitratlösungen

Zusammenfassung Es wurde das polarographische Verhalten von Indium(III) in verschiedenen Nitraten in Abhängigkeit von der Konzentration untersucht. Die Ergebnisse wurden unter besonderer Beachtung der Faktoren Viskosität, Diffusionskoeffizienten und Ionensolvatation interpretiert. Die scheinbaren Geschwindigkeitskonstanten wurden nach dem Verfahren vonDelahay bestimmt und ein quasireversibles Verhalten festgestellt.

---

Polarography of indium(III) in alkali and alkaline earth nitrates

Polarographic behavior of Indium(III) in several nitrates of varying concentrations has been studied and resuts interpreted in the light of factors viscosity, diffusion coefficients and ion solvation. The apparent rate constants were determined byDelahay's treatment which revealed its quasireversible behavior.

---

---

An den allfällige Korrespondenz zu richten ist.     

Obtaining functional form for chaotic time series evolution using genetic algorithm

A genetic algorithm (GA) based strategy is presented for deducing an exact or near-exact functional form from a time series. The GA formalism proposed here utilizes (i) the "postfix" representation with a view to reduce the procedural complexities and (ii) the "elitist mating" scheme to produce fitter offspring strings. The GA procedure is exemplified by considering chaotic time series of the well-known logistic, Henon and universal maps. The GA correctly recovers the underlying functional forms for the respective time series. Measurements from a number of finite-dimensional physical, biological, and other systems often give rise to complex time series and the presented methodology should prove useful in obtaining functional forms describing accurately the evolution of the time series. (c) 1999 American Institute of Physics.     

Simultaneous estimation of E- and Z-isomers of guggulsterone in rabbit plasma using liquid chromatography tandem mass spectrometry and its application to pharmacokinetic study

A sensitive and selective liquid chromatography/tandem mass spectrometric method was developed for simultaneous determination of E‐ and Z‐guggulsterone isomers (antihyperlipidemic drug) in rabbit plasma. Both the isomers were resolved on a Symmetry‐Shield C₁₈ (5 µm, 4.6 × 150 mm) column, using gradient elution comprising a mobile phase of methanol, 0.5% v/v formic acid and acetonitrile. With dexamethasone as internal standard, plasma samples were extracted by an automated solid‐phase extraction method using C₁₈ cartridges. Detection was performed by electrospray ionization in multiple reaction monitoring (MRM) in positive mode. The calibration curve was linear over the concentration range of 1.56–200 ng/mL (r² ≥ 0.998) for both analytes. The intra‐day and inter‐day accuracy and precision were within −0.96 to 4.12 (%bias) and 2.73 to 8.00 (%RSD) respectively. The analytes were stable after three freeze–thaw cycles. The method was successfully applied to study steriospecific pharmacokinetics of E‐ and Z‐guggulsterone in NZ rabbit. Copyright © 2011 John Wiley & Sons, Ltd.     

Spectrophotometric determination of ruthenium(III) using diphenylcarbazone

Summary The purple violet ruthenium(III)-diphenylcarbazone complex which is formed at p _h 5–7, and has an absorption maximum at 530 nm with molar absorption coefficient 16.2·10⁴l.cm^–1.mole^–1 is suggested for the estimation of 20–125g ruthenium(III) spectrophotometrically in 30–60% ethanol. The complex is stable over p _h range 3.2–8.4. The limits of interference due to foreign ions have been studied.

---

Zusammenfassung Der bei p _h 5 bis7 entstehende Ruthenium(III)-Diphenylcarbazon-Komplex hat ein Absorptionsmaximum bei 530 nm und einen Absorptionskoeffizienten von 16,2·10⁴ l.cm^–1.Mol^–1. Die spektrophotometrische Bestimmung von 20 bis 125g Ruthenium(III) in 30 bis 60%igem Äthanol mit Hilfe dieses zwischen p _h 3,2 und 8,4 beständigen Komplexes wurde vorgeschlagen. Die Störung durch Fremdionen wurde geprüft.

     

Role of partially flocculated sols in emulsion stability

Summary The stability of emulsion of Toluene in water stabilized by partially flocculated ferric hydroxide sol has been studied. The size of the emulsion droplets as determined by size frequency analysis is found to be of 1.1 μ radius. The flocculation studies were carried out haemocytometrically at different amount of electrolytes and at different p_H values. The electrokinetic potential ‘ζ’ was determined micro-electrophoretically at different amounts of electrolytes and also at different p_H's. In the case of tri and tetra valent anions the charge reversal was observed. In the light of the D.V.O. theory the interaction energy profiles were drawn and 2–6 kT deep secondary minima obtained showing thereby the occurrence of reversible flocculation. Degree of aggregation has been calculated theoretically at different values of ‘A’ and the value of A was found to be 1.0×10⁻¹² erg to fit the value of degree of aggregation obtained haemocytometrically. The charge densities and binding parameters have also been calculated.     

A study of nuclear prenylation of 2,4-dihydroxy phenyl benzyl ketone: Syntheses of linear and angular 6″,6″-dimethyl pyrano-isoflavones,and their 2-methyl and 2-phenyl analogues

2,4-Dihydroxyphenyl benzyl ketone (I) condenses with 2-methyl but-3-en-2-ol in the presence of boron trifluoride etherate to afford a mixture of 3-C-, 5-C- and 3,5-di C C-prenyl derivatives separable by chromatography. The above mixture without the 5-C-prenyl but with the 4-O-prenyl derivative results when ketone I is treated with prenyl bromide in the presence of methanolic potash. 3-C-(III a) and 5-C-(IV) prenyl derivatives undergo ready oxidative cyclization with DDQ to yield the corresponding pyrano derivatives VIII and XII respectively which form good starting materials for various isoflavone condensations. Thus both linear and angular 6″,6″-dimethyl pyrano-isoflavones and their 2-methyl and 2-phenyl analogues have been synthesized.     

An efficient biomaterial supported bifunctional organocatalyst (ES-SO3- C5H5NH+) for the synthesis of β-amino carbonyls

A biomaterial supported organocatalyst, readily synthesized by the reaction of chemically modified sulfonic group containing expanded corn starch with pyridine exhibited excellent catalytic activity for the synthesis of β-amino carbonyls in excellent yields via aza-Michael addition of amines to electron deficient alkenes. A remarkable enhancement in the reaction rates was observed with the prepared bifunctional organocatalyst in comparison to the either starch grafted sulfonic acid or the corresponding homogeneous pyridinium p-toluenesulfonate.