Effect of methonolic extract of Vitex negundo on haloperidol induced catalepsy in albino mice

Background: Plants are being used in traditional medicine since history of mankind. The knowledge of these medicinal plants has accrued in the course of many centuries leading to medicinal systems in India such as Ayurveda, Unani and Siddha. Objective: In the present study, we evaluated the anticataleptic efficacy of Vitex negundo, a polyherbal formulation in haloperidol induced catalepsy in mice.Methods: Five groups (n=6) of male albino mice were used in the study. Catalepsy was induced by i.p. administration of haloperidol (1 mg/kg). The degree of catalepsy (cataleptic score) was measured as the time the animal maintained an imposed posture. We compared the anticataleptic efficacy of Vitex negundo (50, 100, 200 mg/kg) with standard received Pheniramine maleate 10 mg/kg, i.p.Results: In vehicle treated animals, haloperidol (1 mg/kg. i.p.) produced the maximum catalepsy at 180 min (46.78±3.78 min). Standard treated as Pheniramine maleate 10 mg/kg, i.p. shows maximum at 120 min. 19.24±1.32. Test herb, i.p. Methanolic extract of Vitex negundo (50, 100, 200 mg/kg, i.p.) significantly potentiated haloperidol induced catalepsy at each time interval, in a dose dependent manner. At dose 50, 100 and 200mg/kg, extract of Vitex negundo (Linn.) roots showed maximum cataleptic score 12.34±0.78, 14.43±0.43 and 15.43±0.67 min, respectively at 120 minutes in haloperidol treated animals.Conclusions: The present study indicates that the methanolic extract of Vitex negundo reduces haloperidol-induced catalepsy in mice

2-D analytical study of employment of thermal barrier coatings to evaluate the performance of actively cooled panels for air breathing engines

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Hypersonic vehicles operate at high flight Mach numbers exposing the airframe and engine structures to high heat loads which are quite severe in the combustor part of the high-speed air breathing engine. In order to withstand high heat loads experienced in the combustor region of the engine during hypersonic flight, actively cooled panels are employed. Herein, a fuel before being injected into the combustor serves as a coolant and is made to flow through the combustor heat exchanger panels such that the material and coolant temperatures are maintained below their critical limits. A few of the candidate materials considered for the active panels of the engine are Nb alloy Cb 752, Ni alloy Inconel X-750, and CSiC. To enhance the heat withstanding capacity of these materials, low thermal conductivity thermal barrier coatings (TBC) are employed. Currently Yttria-Stabilized Zirconia (YSZ) material and ceramic materials are being used as popular TBC materials because of their very low thermal conductivity and high phase stability. In this analytical study, thermal properties of air-plasma-sprayed zirconia based lanthanum zirconate (La2Zr2O7) – LZ- coatings were employed in the investigations. Lanthanum-cerium oxide (La2Ce2O7) –LC- is considered as a new candidate material for TBCs because of its low thermal conductivity and high phase stability. With the use of La2Ce2O7 and La2Zr2O7 as TBC materials, the difference in the weight of the active panel material and the heat gained by the fuel are nearly identical as compared to active panel material coated with YSZ TBC. Results showed that the effect of TBC thickness on the weight of the optimised actively cooled panel is negligible, because of very small TBC layer thickness ranging from 0.5 to 3.0 mm and nearly identical thermal properties of the TBC’s. Results showed that Inconel X-750 is capable of sustaining high heat transfer coefficients with fuel/coolant heat gain well below fuel coking temperature with moderate weight to area ratio.dc201

Molecular packing and intermolecular interactions in two structural polymorphs of N-palmitoylethanolamine, a type 2 cannabinoid receptor agonist

The molecular structure, packing properties, and intermolecular interactions of two structural polymorphs of N-palmitoylethanolamine (NPEA) have been determined by single-crystal X-ray diffraction. Polymorphs α and β crystallized in monoclinic space group P2<SUB>1</SUB>/c and orthorhombic space group Pbca, respectively. In both polymorphs, NPEA molecules are organized in a tail-to-tail manner, resembling a bilayer membrane. Although the molecular packing in polymorph α is similar to that in N-myristoylethanolamine and N-stearoylethanolamine, polymorph β is a new form. The acyl chains in both polymorphs are tilted by ∼35° with respect to the bilayer normal, with their hydrocarbon moieties packed in an orthorhombic subcell. In both structures, the hydroxy group of NPEA forms two hydrogen bonds with the hydroxy groups of molecules in the opposite leaflet, resulting in extended, zig-zag type H-bonded networks along the b-axis in polymorph α and along the a-axis in polymorph β. Additionally, the amide N-H and carbonyl groups of adjacent molecules are involved in N-H···O hydrogen bonds that connect adjacent molecules along the b-axis and a-axis, respectively, in α and β. Whereas in polymorph α the L-shaped NPEA molecules in opposite layers are arranged to yield a Z-like organization, in polymorph β one of the two NPEA molecules is rotated 180°, leading to a W-like arrangement. Lattice energy calculations indicate that polymorph a is more stable than polymorph β by ∼2.65 kcal/mol

Studies on the critical micellar concentration and phase transitions of Stearoylcarnitine

The critical micellar concentration (CMC) of stearoylcarnitine was determined at different pH values at room temperature by fluorescence spectroscopy, monitoring the spectral changes of 8-anilinonaphthalene-1-sulfonate (ANS). The CMC was found to vary with pH, increasing from about 10 μM at pH 3.0 to ca. 25 μM at pH 7.0, but decreasing slightly with further increase in pH to approximately 19 μM at pH 10.0. Differential scanning calorimetry (DSC) shows that stearoylcarnitine dispersed in water at low concentration undergoes a broad thermotropic phase transition at 44.5°C, with a transition enthalpy of 15.0 kcal/mol. The transition temperature (T<SUB>t</SUB>) shifts to ca. 50.5°C in the presence of 1 mM EDTA or when the concentration is increased significantly. The turbidity of aqueous dispersions of stearoylcarnitine was found to be considerably high at low temperatures, which decreases quite abruptly over a short temperature range, indicating that a transition occurs from a phase of large aggregates to one of much smaller aggregates, most likely micelles. The phase transition temperature was determined as 29.1°C at pH 3.0, which increased with increasing pH up to a value of 55.3°C at pH 8.6 and remains nearly constant thereafter up to pH 11.2. The pH dependence of CMC and T<SUB>t</SUB> suggest that the pK<SUB>a</SUB> of the carboxyl group of long chain acylcarnitines shifts to higher temperatures upon aggregation (micelles or bilayer membranes)

Interaction of N-myristoylethanolamine with cholesterol investigated in a Langmuir film at the air–water interface

The dramatic increase in the content of N-acylethanolamines (NAEs) having different acyl chains in various tissues when subjected to stress has resulted in significant interest in investigations on these molecules. Previous studies suggested that N-myristoylethanolamine (NMEA) and cholesterol interact to form a 1:1 (mol/mol) complex. In studies reported here, pressure-area isotherms of Langmuir films at the air-water interface have shown that at low fractions of cholesterol, the average area per molecule is lower than that predicted for ideal mixing, whereas at high cholesterol content the observed molecular area is higher, with a cross-over point at the equimolar composition. A plausible model that can explain these observations is the following: addition of small amounts of cholesterol to NMEA results in a reorientation of the NMEA molecules from the tilted disposition in the crystalline state to the vertical and stabilization of the intermolecular interactions, leading to the formation of a compact monolayer film, whereas at the other end of the composition diagram, addition of small amounts of NMEA to cholesterol leads to a tilting of the cholesterol molecules resulting in an increase in the average area per molecule. In Brewster angle microscopy experiments, a stable and bright homogeneous condensed phase was observed at a relatively low applied pressure of 2 mN.m -1 for the NMEA:Chol. (1:1, mol/mol) mixture, whereas all other samples required significantly higher pressures (&gt;10 mN.m-1) to form a homogeneous condensed phase. These observations are consistent with the formation of a 1:1 stoichiometric complex between NMEA and cholesterol and suggest that increase in the content of NAEs under stress may modulate the composition and dynamics of lipid rafts in biological membranes, resulting in alterations in signaling events involving them, which may be relevant to the putative cytoprotective and stress-combating ability of NAEs

Structure, phase behaviour and membrane interactions of N-acylethanolamines and N-acylphosphatidylethanolamines

N-Acylethanolamines (NAEs) and N-acylphosphatidylethanolamines (NAPEs) are naturally occurring membrane lipids, whose content increases dramatically in a variety of organisms when subjected to stress, suggesting that they may play a role in the stress-combating mechanisms of organisms. In the light of this, it is of great interest to characterize the structure, physical properties, phase transitions and membrane interactions of these two classes of lipids. This review will present the current status of our understanding of the structure and phase behaviour of NAEs and NAPEs and their interaction with major membrane lipids, namely phosphatidylcholine, phosphatidylethanolamine and cholesterol. The relevance of such interactions to the putative stress-combating and membrane stabilizing properties of these lipids will also be discussed

N-Myristoylethanolamine-cholesterol (1:1) complex: first evidence from differential scanning calorimetry, fast-atom-bombardment mass spectrometry and computational modelling

The interaction of N-myristoylethanolamine (NMEA) with cholesterol is investigated by differential scanning calorimetry (DSC), fast-atom-bombardment mass spectrometry (FAB-MS) and computational modelling. Addition of cholesterol to NMEA leads to a new phase transition at 55°C besides the chain-melting transition of NMEA at 72.5°C. The enthalpy of the new transition increases with cholesterol content up to 50 mol%, but decreases thereafter, vanishing at 80 mol%. The enthalpy of the chain-melting transition of NMEA decreases with an increase in cholesterol; the transition disappears at 50 mol%. FAB-MS spectra of mixtures of NMEA and cholesterol provide clear signatures of the formation of {[NMEA+cholesterol]+} {[NMEA+cholesterol+Na]+}. These results are consistent with the formation of a 1:1 complex between NMEA and cholesterol. Molecular modelling studies support this experimental finding and provide a plausible structural model for the complex, which highlights multiple H-bond interactions between the hydroxy group of cholesterol and the hydroxy and carbonyl groups of NMEA besides appreciable dispersion interaction between the hydrocarbon domains of the two molecules

Structure and Thermotropic Phase Behavior of a Homologous Series of Bioactive <i>N</i>‑Acyldopamines

<i>N</i>-Acyldopamines (NADAs), which are present in mammalian nervous tissues, exhibit interesting biological and pharmacological properties. In the present study, a homologous series of NADAs with varying acyl chains (<i>n</i> = 12–20) have been synthesized and characterized. Differential scanning calorimetric studies show that in the dry state the transition temperatures, enthalpies, and entropies of NADAs exhibit odd–even alternation with the values corresponding to the even chain length series being slightly higher. Both even and odd chain length NADAs display a linear dependence of the transition enthalpies and entropies on the chain length. However, odd–even alternation was not observed in the calorimetric properties upon hydration, although the transition enthalpies and entropies exhibit linear dependence. Linear least-squares analyses yielded incremental values contributed by each methylene group to the transition enthalpy and entropy and the corresponding end contributions. <i>N</i>-Lauroyldopamine (NLDA) crystallized in the monoclinic space group <i>C</i>2/<i>c</i> with eight symmetry-related molecules in the unit cell. Single-crystal X-ray diffraction studies show that NLDA molecules are organized in the bilayer form, with a head-to-head (and tail-to-tail) arrangement of the molecules. Water-mediated hydrogen bonds between the hydroxyl groups of the dopamine moieties of opposing layers and N–H···O hydrogen bonds between the amide groups of adjacent molecules in the same layer stabilize the crystal packing. These results provide a thermodynamic and structural basis for investigating the interaction of NADAs with other membrane lipids, which are expected to provide clues to understand how they function <i>in vivo</i>, e.g., as signaling molecules in the modulation of pain