Enzymatic Synthesis of Naringin Palmitate

2012 ◽  
Vol 554-556 ◽  
pp. 1350-1356 ◽  
Author(s):  
Xia Zhang ◽  
Lin Li ◽  
Jian Rong Huang ◽  
Ling Chen ◽  
Xiao Xi Li ◽  
...  

Naringin esters are paid more attention in medical and functional food industry than naringin due to their higher stability and solubility in lipidic environments. Naringin palmitic acid esters were enzymatically synthesized with naringin and palmitic acid. The effects of solvent type, temperature, concentration and types of enzymes and the molar ratio of substrates on the conversion of naringin were investigated. Novozym 435 performed higher catalytic ability in tert-amyl alcohol in the esterification of naringin with palmitic acid. The conversion yield of naringin increased with the increase of temperature (30-70°C) and of the concentration of enzyme. The structure of the naringin palmitate was characterized by FT-IR, 1H-NMR and HPLC-MS. 1H-NMR spectroscopic analysis indicated the presence of an ester bond on the C-6 of the glucose moiety of naringin molecule.

2010 ◽  
Vol 93-94 ◽  
pp. 13-16
Author(s):  
Khalil J. Asali

Reactions of the labile complex (Me3tach)M(CO)3 (Me3tach = 1,3,5-trimethyl-1,3,5-triazacyclohexane; M = W, Mo) with bis(phenylthio)alkanes ( = PhS(CH2)nSPh), (2:3 molar ratio) in CH2Cl2 as solvent (at 35 oC M = W, 0 oC M = Mo) afforded in good yields bimetallic tricarbonyl complexes triply- bridged by bis(phenylthio)alkanes of the type [M(CO)3]2(μ-PhS-(CH2)n-SPh)3 [n = 3 (a), 4 (b), 5 (c), 6 (d); M = W (1), Mo (2)]. These new triply-bridged complexes were characterized by 1H NMR, FT-IR and elemental analysis. Additionally, it has been observed that the thermodynamic stability of some of these new complexes in chlorinated hydrocarbons depends mainly on the nature of the metal center and varies in the order W >> Mo.


2011 ◽  
Vol 228-229 ◽  
pp. 919-924 ◽  
Author(s):  
Feng Yuan Huang

Cellulose Stearate (CS) was synthesized by acylating microcrystalline cellulose (MCC) in homogeneous system with p-toluenesulfonyl chloride (Tos-Cl) and stearic acid (SA). The reactive conditions were discussed. The molar ratio of AGU:SA:Tos-Cl was the key factor which affected the degree of substitution (DS) of CS. In the present paper, CSs with DS ranging from 0.64 to 2.35 were prepared under mild condition. The structure of CS was characterized by FT-IR and 1H-NMR, and DS of CS was determined by traditional saponification method and 1H-NMR, respectively. The solubility of CS was also investigated; the results showed that the higher DS of CS was, the easier CS dissolved in organic solvents. The thermal analysis was measured with DSC, and the results indicated that the glass transition temperature (Tg) and the maximum temperature of thermal decomposition (Tmax) of CS were dependent on DS.


2020 ◽  
Vol 10 (6) ◽  
pp. 547
Author(s):  
Sabour Abderrahman ◽  
El Asbahani Abdelhafed ◽  
Lacherai Abdellah ◽  
El Ouadi Brahim ◽  
Jilale Abderrahim

<p class="ElsKeyword">In this study, we described an original, new, simple, and productive one-pot method for Thymol para-sulfonation by using thionyl chloride (SOCl<sub>2</sub>) as a sulfonating agent under mild conditions. Spectroscopic analysis by FT-IR, mass spectrometry, and NMR 1H and 13C confirmed the structure of the parasulfonated derivative of Thymol:  the 4-hydroxy-5-isopropyl-2-methylbenzenesulfonic acid. An optimization study was carried out to perform and improve the yield of this new para-sulfonation method by studying the effect of three parameters: temperature, the molar ratio (η) of the reactants, and solvents. The obtained results showed that the use of cyclohexane as a solvent, a molar ratio greater or equal than 3, and working under low temperatures increase the yield of this parasulfonation considerably to reach adequately 91.3%.</p>


Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1832-P
Author(s):  
ANNA SANTORO ◽  
PENG ZHOU ◽  
YAN ZHU ◽  
ODILE D. PERONI ◽  
ANDREW T. NELSON ◽  
...  

2018 ◽  
Vol 63 (1-2) ◽  
pp. 49-60
Author(s):  
R. Crainic ◽  
◽  
L. R. Drăgan ◽  
R. Fechete ◽  
◽  
...  

2020 ◽  
Vol 16 (5) ◽  
pp. 816-828
Author(s):  
Gurdeep Rattu ◽  
Nishtha Khansili ◽  
Prayaga M. Krishna

Background: Cerium oxide nanoparticles (nanoceria) are efficient free-radical scavengers due to their dual valence state and thus exhibit optical and catalytic properties. Therefore, the main purpose of this work was to understand the peroxidase mimic activity of polymer-stabilized nanoceria for enzyme-less H2O2 sensing by fluorescence spectrometer. Objective: This research revealed the development of fluorescence hydrogen peroxide nanosensor based on the peroxidase-like activity of polyacrylic acid stabilized nanoceria (PAA-CeO2 Nps). Methods: PAA-CeO2 Nps were synthesized by simple cross-linking reaction at a low temperature and characterized by XRD, SEM, Zeta potential, TGA, FT-IR and UV-VIS spectroscopic analysis. H2O2 sensing was performed by a fluorescence spectrometer. Results:: The synthesized polymer nanocomposite was characterized by XRD, SEM, TGA, FT-IR and UV-VIS spectroscopic analysis. The XRD diffraction patterns confirmed the polycrystalline nature and SEM micrograph showed nanoparticles having hexagonal symmetry and crystallite size of 32 nm. The broad peak of Ce–O bond appeared at 508 cm-1. UV-VIS measurements revealed a welldefined absorbance peak around 315 nm and an optical band-gap of 3.17 eV. As synthesized PAACeO2 Nps effectively catalysed the decomposition of hydrogen peroxide (H2O2) into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. Under optimized conditions, the linear range for determination of hydrogen peroxide was 0.01 - 0.2 mM with a limit of detection (LOD) of 1.2 μM. Conclusion: The proposed method is ideally suited for the sensing of H2O2 at a low cost and this detection system enabled the sensing of analytes (sugars), which can enzymatically generate hydrogen peroxide.


2011 ◽  
Vol 197-198 ◽  
pp. 1153-1156
Author(s):  
Ning Chen ◽  
Ya Bin Li

The characteristics of host-guest complexes between cucurbit[n]uril (CB [n]) and phenylalanine were investigated by UV-visible absorption spectroscopy in acetate buffer solution at room temperature. It was found that the UV-visible absorption increased steadily with constantly dropping the high concentration of cucurbit[6]uril (CB [6]) and cucurbit[8]uril (CB [8]) in the phenylalanine solution which indicates that there are some interaction betweenCB [n] and phenylalanine.Then CB [6] and phenylalanine at molar ratio of 1:1 to weigh while CB [8] and phenylalanine at molar ratio of 1:2, respectively, are both demonstrated by 1H NMR spectra. 1H NMR spectrum of complexes was obtained, indicating an enthalpic driving force for host-guest complexes. The possible interaction mechanism and inclusion mode were also discussed. This work may extend the application range of CB [n] in supramolecular and pharmaceutical analysis.


Biocatalysis ◽  
1990 ◽  
Vol 3 (4) ◽  
pp. 295-305 ◽  
Author(s):  
Akihiko Nagao ◽  
Makoto Kito

Author(s):  
Vijay A. Juwar ◽  
Ajit P. Rathod

Abstract The present study deals with the treatment of complex waste (WW) treated for removal of chemical oxygen demand (COD) of the food industry by a sono-Fenton process using a batch reactor. The response surface methodology (RSM) was employed to investigate the five independent variables, such as reaction time, the molar ratio of H2O2/Fe2+, volume ratio of H2O2/WW, pH of waste, and ultrasonic density on COD removal. The experimental data was optimized. The optimization yields the conditions: Reaction time of 24 min, HP:Fe molar ratio of 2.8, HP:WW volume ratio of 1.9 ml/L, pH of 3.6 and an ultrasonic density of 1.8 W/L. The predicted value of COD was 91% and the experimental result was 90%. The composite desirability value (D) of the predicted percent of COD removal at the optimized level of variables was close to one (D = 0.991).


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