Raman spectroscopic approach to monitor the in vitro cyclization of creatine→creatinine

Gangopadhyay, Debraj; Sharma, Priyanka; Singh, Sachin Kumar; Singh, Prabha; Tarcea, N.; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.

doi:10.1016/j.cplett.2014.11.021

Cited by 12 publications

(10 citation statements)

References 23 publications

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“…Raman spectroscopic technique and ab initio calculations have been widely used for monitoring chemical reactions, understanding the precise structural changes occurring in the course of the reaction and other in vitro studies. − In the present study, we have focused on this conversion, that is, the cyclization of NAC to its cyclic isomer MTCA by investigating the structural changes in an aqueous solution of NAC at five different basic pH values in vitro by time series Raman spectral analysis. Ab initio studies involving calculation of intermediate stages and transition states causing the various structural changes in NAC at basic pH have also been done and correlated with the Raman spectral data to infer a plausible pathway of cyclization of NAC at basic pH.…”

Section: Introductionmentioning

confidence: 99%

Monitoring the in Vitro Thiazolidine Ring Formation of Antioxidant Drug N-Acetyl-l-cysteine at Basic pH and Detection of Reaction Intermediates: A Raman Spectroscopic and Ab Initio Study

et al. 2018

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The important cyclization reaction of antioxidant drug N-acetyl-L-cysteine (NAC) has been monitored in vitro at basic pH with the help of time series Raman spectroscopy. The thiazoline ring formation of NAC at acidic pH is a well-known reaction and has been studied extensively. However, the formation of a thiazolidine ring from NAC at basic pH has not been investigated precisely till date. The effect of basicity of the medium on the rate of cyclization has been investigated by studying the reaction at five different basic pH values. Raman signatures of cyclization have been observed with the passage of time and are found to appear faster as the basicity of the medium increases. Ab initio calculations have been done to understand the plausible mechanism of the reaction at basic pH. It is observed that formation of a thiazolidine ring from NAC occurs primarily in four steps, which involve proton abstraction from the thiol (SH) group of NAC and subsequent formation of an S−C bond by a nucleophilic attack of the C−S group on the protonated C−O−H group in NAC. Correlation of the theoretically calculated results with experimental Raman spectral analysis has led to a detailed and proper understanding of this important biochemical reaction.

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Section: Introductionmentioning

confidence: 99%

Monitoring the in Vitro Thiazolidine Ring Formation of Antioxidant Drug N-Acetyl-l-cysteine at Basic pH and Detection of Reaction Intermediates: A Raman Spectroscopic and Ab Initio Study

et al. 2018

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“…Substitution levels above 15% of caffeine showed more similarities with fewer samples of the other substances used. The score plot ( Figure 6C) showed only three lactose concentrations (30,45 and 50%) and concentrations above 20% of creatine showed in the positive scale of PC3. The decrease of intense protein related peaks might be influencing this principal component, which can be clarified by analyzing the loading plots (Figure 7).…”

Section: Principal Components Analysismentioning

confidence: 99%

Mid Infrared Spectroscopy and Multivariate Analysis Evaluation of Adulteration in Whey Protein Powder

Andrade

Pereira

Ranquine

et al. 2020

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Mid infrared (MIR) spectroscopy was combined with multivariate approaches Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression to assess modifications in spectral profile of whey protein concentrate (WPC) powder due to changes in formulation level using caffeine, creatine and lactose, simulating fraud. Adulterations were made by replacing WPC in different levels from 5 to 50% (w/w - 5% steps) with three adulterants in separate. The spectra comparison of the samples allowed the identification of peaks associated to characteristic chemical bonds of each adulterant. PCA was carried out and 89% of the total variability of the spectral data was explained by three principal components, which allowed the confirmation of variables influencing each sample mixture and validating the spectral observations. Above 20% decrease in WPC content (20% adulteration), it was possible to differentiate all the three substances used. Predictions of percentage of WPC substitution were made through PLS regressions. The best prediction models were: lactose > creatine > caffeine. However, predictions resulted in overall good accuracy, low relative errors and coefficients of determination of fitting of calibration and validation curves above 0.97 in all cases. Therefore, techniques employed here aid the quality assessment of food products as alternative analytical tools.

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“…For visualization of optimised structures and vibrational modes, the GaussView 4.2 programme was employed . In the studies reported by our group, density functional theory (DFT) calculations with B3LYP method using 6‐311++G(d,p) basis set gave quite nice results in terms of structure–spectra correlation, and several meaningful conclusions could be drawn from the experimental results. To include dispersion correction the energies of optimised structures have been calculated at WBX97XD/6‐311++G(d,p) level of theory.…”

Section: Theoretical Detailsmentioning

confidence: 99%

A novel Raman spectroscopic approach to identify polymorphism in leflunomide: a combined experimental and theoretical study

Sharma

Gangopadhyay

Umrao

et al. 2015

J Raman Spectroscopy

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Polymorphism is an important characteristic which affects the activity, solubility and other physical properties of a compound and can be induced by varying temperature, pressure and solvent. The presence and conversion of α to β polymorphic forms of an anti‐rheumatic drug leflunomide have been studied by temperature‐dependent and in situ Raman observations. Both α and β polymorphs were found to co‐exist in the temperature interval 367–372 K. The α form alone exists below 367 K and the β form alone above 373 K. The CO stretching band clearly demonstrates the α → β conversion because of breaking of N–H···O bond and formation of N–H···N bond. On cooling the Raman spectra suggest the irreversibility of this conversion. Thermodynamic stability, crystal parameters and surface morphology of both forms in the leflunomide powder used for the present study have been verified by differential scanning calorimetry, X‐ray powder diffraction and scanning electron microscopy. Copyright © 2015 John Wiley & Sons, Ltd.

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Raman spectroscopic approach to monitor the in vitro cyclization of creatine→creatinine

Cited by 12 publications

References 23 publications

Monitoring the in Vitro Thiazolidine Ring Formation of Antioxidant Drug N-Acetyl-l-cysteine at Basic pH and Detection of Reaction Intermediates: A Raman Spectroscopic and Ab Initio Study

Monitoring the in Vitro Thiazolidine Ring Formation of Antioxidant Drug N-Acetyl-l-cysteine at Basic pH and Detection of Reaction Intermediates: A Raman Spectroscopic and Ab Initio Study

Mid Infrared Spectroscopy and Multivariate Analysis Evaluation of Adulteration in Whey Protein Powder

A novel Raman spectroscopic approach to identify polymorphism in leflunomide: a combined experimental and theoretical study

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