scholarly journals Attenuated Structural Transformation of Aconitine during Sand Frying Process and Antiarrhythmic Effect of Its Converted Products

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yu-Jie Wang ◽  
Pei Tao ◽  
Yan Wang
Keyword(s):  
Structural Transformation ◽  
Onset Time ◽  
Antiarrhythmic Activity ◽  
Antiarrhythmic Effect ◽  
Diterpenoid Alkaloids ◽  
Frying Process ◽  
Arrhythmogenic Effect ◽  
Equal Dose ◽  
Transformation Pathway ◽  
Transformation Pathways

The transformation pathways of diterpenoid alkaloids have been clarified in the boiling and steaming process. Aconitine, a famous diterpenoid alkaloid, is successively transformed into benzoylaconine and aconine during the processes of boiling and steaming, but the transformation pathway remains to be determined in the sand frying process. The present study aims at investigating the transformation pathways of aconitine in the process of sand frying, as well as assessing the cardiotoxicity and antiarrhythmic activity of aconitine and its converted products. The parameters of temperature and time for the structural transformation of aconitine were confirmed by HPLC. The converted products were further separated and identified by column chromatography, NMR, and HR-ESI-MS. Furthermore, by observing the lead II electrocardiogram (ECG) changes in rats under an equivalent dose, the cardiotoxicity of aconitine and its converted products were compared. Ultimately, the antiarrhythmic effect of the converted products was investigated by employing the model of aconitine-induced arrhythmia. Consequently, the structure of aconitine was converted when processed at 120°C–200°C for 1–40 min. Two diterpenoid alkaloids, a pair of epimers, namely, pyroaconitine and 16-epi-pyroaconitine, were further isolated from processed aconitine. 0.03 mg/kg aconitine induced arrhythmias in normal rats, while the converted products did not exhibit arrhythmias under an equal dose. In the antiarrhythmic assay, 16-epi-pyroaconitine could dose-dependently delay the onset time of VPB, reduce the incidence of VT, and increase the arrhythmia inhibition rate, demonstrating comparatively strong antiarrhythmic activity. Conclusively, compared with the prototype compound aconitine, the converted products exhibited lower cardiotoxicity. Further investigations on the cardiotoxicity indicated that pyroaconitine with β configuration had a stronger cardiotoxicity than 16-epi-pyroaconitine with α configuration. Furthermore, 16-epi-pyroaconitine could antagonize the arrhythmogenic effect caused by the prototype compound aconitine; the antiarrhythmic effect of 16-epi-pyroaconitine was stronger than lidocaine and propafenone, which had the potential to be developed as antiarrhythmic drugs.

scholarly journals Attenuation and Structural Transformation of Crassicauline A During Sand Frying Process and Antiarrhythmic Effects of its Transformed Products

2021 ◽  
Vol 12 ◽  
Author(s):  
Pei Tao ◽  
Yan Wang ◽  
Yujie Wang
Keyword(s):  
Antiarrhythmic Drugs ◽  
Parent Compound ◽  
Antiarrhythmic Activity ◽  
Ventricular Premature Beat ◽  
Antiarrhythmic Agents ◽  
Diterpenoid Alkaloids ◽  
Activity Data ◽  
Frying Process ◽  
Transformation Pathways ◽  
Antiarrhythmic Effects

To ensure safety and efficacy, most Aconitum herbs should be processed before clinical application. The processing methods include boiling, steaming, and sand frying. Among these methods, the transformation pathways of diterpenoid alkaloids in the process of sand frying are more complicated. Therefore, crassicauline A, a natural product with two ester bonds, was chosen as the experimental object. Consequently, a known alkaloid, together with three new alkaloids, was derived from crassicauline A. Meanwhile, the cardiotoxicity of converted products was reduced compared with their parent compound. Interestingly, some diterpenoid alkaloids have similar structures but opposite effects, such as arrhythmia and antiarrhythmic. Considering the converted products are structural analogues of crassicauline A, herein, the antiarrhythmic activity of the transformed products was further investigated. In a rat aconitine-induced arrhythmia assay, the three transformed products, which could dose-dependently delay the ventricular premature beat (VPB) incubation period, reduce the incidence of ventricular tachycardia (VT), combined with the increasing arrhythmia inhibition rate, exhibited prominent antiarrhythmic activities. Our experiments speculated that there might be at least two transformation pathways of crassicauline A during sand frying. The structure-activity data established in this paper constructs the critical pharmacophore of diterpenoid alkaloids as antiarrhythmic agents, which could be helpful in searching for the potential drugs that are equal or more active and with lower toxicity, than currently clinical used antiarrhythmic drugs.

scholarly journals Comparing crystal structures with symmetry and geometry

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
John C. Thomas ◽  
Anirudh Raju Natarajan ◽  
Anton Van der Ven
Keyword(s):  
Combinatorial Optimization ◽  
Crystal Structures ◽  
Structural Transformation ◽  
Infinite Number ◽  
First Principles ◽  
Materials Science ◽  
Crystal Symmetry ◽  
Similarity Metrics ◽  
Mapping Algorithm ◽  
Transformation Pathways

AbstractMeasuring the similarity between two arbitrary crystal structures is a common challenge in crystallography and materials science. Although there are an infinite number of ways to mathematically relate two crystal structures, only a few are physically meaningful. Here we introduce both a geometry-based and a symmetry-adapted similarity metric to compare crystal structures. Using crystal symmetry and combinatorial optimization we describe an algorithm to arrive at the structural relationship that minimizes these similarity metrics across all possible maps between any pair of crystal structures. The approach makes it possible to (i) identify pairs of crystal structures that are identical, (ii) quantitatively measure the similarity between crystal structures, and (iii) find and rank structural transformation pathways between any pair of crystal structures. We discuss the advantages of using the symmetry-adapted cost metric over the geometric cost. Finally, we show that all known structural transformation pathways between common crystal structures are recovered with the mapping algorithm. The methodology presented in this study will be of value to efforts that seek to catalogue crystal structures, identify structural transformation pathways or prune large first-principles datasets used to parameterize on-lattice Hamiltonians.

ChemInform Abstract: Antiarrhythmic Activity of Diterpenoid Alkaloids of the Napelline Type and Their Acylated Derivatives (I)-(III).

ChemInform ◽  
2010 ◽  
Vol 32 (42) ◽  
pp. no-no
Author(s):  
N. Kh. Shakhidoyatova ◽  
F. N. Dzhakhangirov ◽  
M. N. Sultankhodzhaev
Keyword(s):  
Antiarrhythmic Activity ◽  
Diterpenoid Alkaloids

The Antiarrhythmic Effect of 4-Methyl-2,6-Diisobornylphenol in Myocardial Ischemia/Reperfusion

2016 ◽  
Vol 683 ◽  
pp. 469-474 ◽  
Author(s):  
Tatyana Plotnikova ◽  
Mark Plotnikov ◽  
Galina Chernysheva ◽  
Vera Smol'yakova ◽  
Pyotr P. Shchetinin ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Ischemia Reperfusion ◽  
Antiarrhythmic Activity ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Antiarrhythmic Effect ◽  
Control Group ◽  
Acute Ischemia ◽  
Sterically Hindered Phenols ◽  
Myocardial Ischemia Reperfusion

We studied the antiarrhythmic activity of novel sterically hindered phenols – 4-methyl-2,6- diisobornylphenol (dibornol) in acute myocardial ischemia/reperfusion in male Wistar rats. Left coronary artery occlusion (10 min) in control group induced different ventricular arrhythmia and 23% mortality of animals. Dibornol (p.o. administration 100 mg/kg 24 and 3 hours before ischemia) did not change the frequency and kinds of arrhythmia in acute ischemia, but significantly reduced the frequency and the level of seriousness of arrhythmia in the reperfusion period, decreased the mortality of rats due to lethal arrhythmia.

Prevention of reperfusion-induced ventricular arrhythmias in isolated rat heart with magnesium

1990 ◽  
Vol 68 (6) ◽  
pp. 694-699 ◽  
Author(s):  
Antoine Bril ◽  
Luc Rochette
Keyword(s):  
Rat Heart ◽  
Marked Change ◽  
Antiarrhythmic Activity ◽  
Isolated Rat Heart ◽  
Antiarrhythmic Effect ◽  
Magnesium Concentration ◽  
Coronary Artery Ligation ◽  
Reperfusion Arrhythmias ◽  
Artery Ligation ◽  
Isolated Rat

The effects of magnesium (from 1.2 to 7.2 mM) were investigated in isolated perfused rat heart subjected to coronary artery ligation and reperfusion. Increasing magnesium concentrations, of the medium containing 3.00 mM of calcium, induced a significant bradycardia and a protective effect towards reperfusion arrhythmias. A significant correlation was found between the heart rate and the antiarrhythmic activity of increasing magnesium concentrations. The effects of high magnesium concentration (4.8 mM) were also investigated after labelling of internal stores of noradrenaline with [3H]noradrenaline. Without any marked change in the pattern of release of radioactivity, a significant reduction of the sudden release of radioactivity was observed during the reperfusion. However, magnesium did not change the uptake of noradrenaline by the heart. Our results suggest that the antiarrhythmic effect of magnesium might be of importance in the clinical treatment of myocardial ischemia.Key words: magnesium, isolated rat heart, reperfusion, arrhythmias, noradrenaline.

Structural Transformation Pathways of Alkaline Earth Family Coordination Polymers Containing 3,3′,5,5′‐Biphenyl Tetracarboxylic Acid

2019 ◽  
Vol 14 (11) ◽  
pp. 1970-1976 ◽  
Author(s):  
Guo‐Dong Lu ◽  
Zhi‐Hui Zhang ◽  
Ya‐Yan Tong ◽  
Xiao‐Meng Liu ◽  
Xiao‐Fan Ma ◽  
...  
Keyword(s):  
Structural Transformation ◽  
Coordination Polymers ◽  
Alkaline Earth ◽  
Tetracarboxylic Acid ◽  
Transformation Pathways

The structure of pre-mRNA and mRNA from erythroid cells

1978 ◽  
Vol 36 (2) ◽  
pp. 234-235
Author(s):  
A.-M. Ladhoff ◽  
B.J. Thiele ◽  
Ch. Coutelle ◽  
S. Rosenthal
Keyword(s):  
Bone Marrow ◽  
Structural Transformation ◽  
Electron Micrographs ◽  
Ammonium Acetate ◽  
Bone Marrow Cells ◽  
Erythroid Cells ◽  
Globin Mrna ◽  
Ordered Structures ◽  
Rabbit Bone ◽  
Rabbit Reticulocytes

The suggested precursor-product relationship between the nuclear pre-mRNA and the cytoplasmic mRNA has created increased interest also in the structure of these RNA species. Previously we have been published electron micrographs of individual pre-mRNA molecules from erythroid cells. An intersting observation was the appearance of a contour, probably corresponding to higher ordered structures, on one end of 10 % of the pre-mRNA molecules from erythroid rabbit bone marrow cells (Fig. 1A). A virtual similar contour was observed in molecules of 9S globin mRNA from rabbit reticulocytes (Fig. 1B). A structural transformation in a linear contour occurs if the RNA is heated for 10 min to 90°C in the presence of 80 % formamide. This structural transformation is reversible when the denatured RNA is precipitated and redissolved in 0.2 M ammonium acetate.

Structural Transformation of a Germanium Σ=13 (510) [001] Tilt Grain Boundary under the Electron Beam

1990 ◽  
Vol 48 (1) ◽  
pp. 52-53 ◽  
Author(s):  
Jean-Luc Rouvière ◽  
Alain Bourret
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundary ◽  
Structural Transformation ◽  
Mirror Symmetry ◽  
High Resolution Electron Microscopy ◽  
Structural Transformations ◽  
Covalent Bonds ◽  
Resolution Electron ◽  
Tilt Grain Boundary

The possible structural transformations during the sample preparations and the sample observations are important issues in electron microscopy. Several publications of High Resolution Electron Microscopy (HREM) have reported that structural transformations and evaporation of the thin parts of a specimen could happen in the microscope. Diffusion and preferential etchings could also occur during the sample preparation.Here we report a structural transformation of a germanium Σ=13 (510) [001] tilt grain boundary that occurred in a medium-voltage electron microscopy (JEOL 400KV).Among the different (001) tilt grain boundaries whose atomic structures were entirely determined by High Resolution Electron Microscopy (Σ = 5(310), Σ = 13 (320), Σ = 13 (510), Σ = 65 (1130), Σ = 25 (710) and Σ = 41 (910), the Σ = 13 (510) interface is the most interesting. It exhibits two kinds of structures. One of them, the M-structure, has tetracoordinated covalent bonds and is periodic (fig. 1). The other, the U-structure, is also tetracoordinated but is not strictly periodic (fig. 2). It is composed of a periodically repeated constant part that separates variable cores where some atoms can have several stable positions. The M-structure has a mirror glide symmetry. At Scherzer defocus, its HREM images have characteristic groups of three big white dots that are distributed on alternatively facing right and left arcs (fig. 1). The (001) projection of the U-structure has an apparent mirror symmetry, the portions of good coincidence zones (“perfect crystal structure”) regularly separate the variable cores regions (fig. 2).

Stimulus onset-to-onset time determines the dichotic temporal order threshold

2001 ◽  
Author(s):  
Harvey Babkoff ◽  
Elisheva Ben-Artzi ◽  
Leah Fostick
Keyword(s):  
Temporal Order ◽  
Onset Time ◽  
Stimulus Onset
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