scholarly journals Urease Inhibitory Kinetic Studies of Various Extracts and Pure Compounds from Cinnamomum Genus

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3803
Author(s):  
Manoj Kumar ◽  
Neha Sikri ◽  
Sulekha Chahal ◽  
Jitender Sharma ◽  
Bhavna Sharma ◽  
...  
Keyword(s):  
Methanol Extract ◽  
Carbonic Acid ◽  
Competitive Inhibition ◽  
Kinetic Studies ◽  
Hexane Fraction ◽  
Hydrolysis Rate ◽  
Carbamic Acid ◽  
Peptic Ulcers ◽  
Urease Enzyme ◽  
Pure Compounds

Urease is an enzyme that plays a significant role in the hydrolysis of urea into carbonic acid and ammonia via the carbamic acid formation. The resultant increase in pH leads to the onset of various pathologies such as gastric cancer, urolithiasis, hepatic coma, hepatic encephalopathy, duodenal ulcers and peptic ulcers. Urease inhibitors can reduce the urea hydrolysis rate and development of various diseases. The Cinnamomum genus is used in a large number of traditional medicines. It is well established that stem bark of Cinnamomum cassia exhibits antiulcerogenic potential. The present study evaluated the inhibitory effect of seven extracts of Cinnamomum camphora, Cinnamomum verum and two pure compounds Camphene and Cuminaldehyde on urease enzyme. Kinetic studies of potential inhibitors were carried out. Methanol extract (IC50 980 µg/mL) of C. camphora and a monoterpene Camphene (IC50 0.147 µg/mL) possess significant inhibitory activity. The Lineweaver Burk plot analysis suggested the competitive inhibition by methanol extract, hexane fraction and Camphene. The Gas Chromatography-Mass Spectroscopy (GC–MS) analysis of hexane fraction revealed the contribution of various terpenes. The present study targets terpenes as a new class of inhibitors that have potential therapeutic value for further development as novel drugs.

Kinetic Behaviour of Amylase According to pH: A New Perspective for Starch Hydrolysis Process

2020 ◽  
Vol 16 (2) ◽  
pp. 135-144
Author(s):  
Ravneet K. Grewal ◽  
Baldeep Kaur ◽  
Gagandeep Kaur
Keyword(s):  
Metal Ions ◽  
Competitive Inhibition ◽  
Deae Cellulose ◽  
Kinetic Studies ◽  
Cost Effective ◽  
Starch Hydrolysis ◽  
Divalent Metal Ions ◽  
Activity Data ◽  
Time Saving ◽  
Alkaline Conditions

Background: Amylases are the most widely used biocatalysts in starch saccharification and detergent industries. However, commercially available amylases have few limitations viz. limited activity at low or high pH and Ca2+ dependency. Objective: The quest for exploiting amylase for diverse applications to improve the industrial processes in terms of efficiency and feasibility led us to investigate the kinetics of amylase in the presence of metal ions as a function of pH. Methods: The crude extract from soil fungal isolate cultures is subjected to salt precipitation, dialysis and DEAE cellulose chromatography followed by amylase extraction and is incubated with divalent metal ions (i.e., Ca2+, Fe2+, Cu2+, and Hg2+); Michaelis-Menton constant (Km), and maximum reaction velocity (Vmax) are calculated by plotting the activity data obtained in the absence and presence of ions, as a function of substrate concentration in Lineweaver-Burk Plot. Results: Kinetic studies reveal that amylase is inhibited un-competitively at 5mM Cu2+ at pH 4.5 and 7.5, but non-competitively at pH 9.5. Non-competitive inhibition of amylase catalyzed starch hydrolysis is observed with 5mM Hg2+ at pH 9.5, which changes to mixed inhibition at pH 4.5 and 7.5. At pH 4.5, Ca2+ induces K- and V-type activation of amylase catalyzed starch hydrolysis; however, the enzyme has V-type activation at 7mM Ca2+ under alkaline conditions. Also, K- and V-type of activation of amylase is observed in the presence of 7mM Fe2+ at pH 4.5 and 9.5. Conclusion: These findings suggest that divalent ions modulation of amylase is pH dependent. Furthermore, a time-saving and cost-effective solution is proposed to overcome the challenges of the existing methodology of starch hydrolysis in starch and detergent industries.

scholarly journals Pretreatment, Anaerobic Codigestion, or Both? Which Is More Suitable for the Enhancement of Methane Production from Agricultural Waste?

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4175
Author(s):  
Lütfiye Dumlu ◽  
Asli Seyhan Ciggin ◽  
Stefan Ručman ◽  
N. Altınay Perendeci
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Agricultural Waste ◽  
Kinetic Studies ◽  
Antagonistic Effect ◽  
Hydrolysis Rate ◽  
Order Kinetic ◽  
Maximum Enhancement ◽  
Mixing Ratios ◽  
Anaerobic Codigestion

Pretreatment and codigestion are proven to be effective strategies for the enhancement of the anaerobic digestion of lignocellulosic residues. The purpose of this study is to evaluate the effects of pretreatment and codigestion on methane production and the hydrolysis rate in the anaerobic digestion of agricultural wastes (AWs). Thermal and different thermochemical pretreatments were applied on AWs. Sewage sludge (SS) was selected as a cosubstrate. Biochemical methane potential tests were performed by mixing SS with raw and pretreated AWs at different mixing ratios. Hydrolysis rates were estimated by the best fit obtained with the first-order kinetic model. As a result of the experimental and kinetic studies, the best strategy was determined to be thermochemical pretreatment with sodium hydroxide (NaOH). This strategy resulted in a maximum enhancement in the anaerobic digestion of AWs, a 56% increase in methane production, an 81.90% increase in the hydrolysis rate and a 79.63% decrease in the technical digestion time compared to raw AWs. On the other hand, anaerobic codigestion (AcoD) with SS was determined to be ineffective when it came to the enhancement of methane production and the hydrolysis rate. The most suitable mixing ratio was determined to be 80:20 (Aws/SS) for the AcoD of the studied AWs with SS in order to obtain the highest possible methane production without any antagonistic effect.

Reactions involving CO2, H2O, and NH3: The formation of (i) carbamic acid, (ii) urea, and (iii) carbonic acid

1986 ◽  
Vol 7 (3) ◽  
pp. 283-293 ◽  
Author(s):  
A. D. Buckingham ◽  
N. C. Handy ◽  
J. E. Rice ◽  
K. Somasundram ◽  
C. Dijkgraaf
Keyword(s):  
Carbonic Acid ◽  
Carbamic Acid

Rarely Occurring Natural Products Isolated from Vincetoxicum stocksii

2019 ◽  
Vol 41 (4) ◽  
pp. 695-695
Author(s):  
Saima Khan Saima Khan ◽  
Muhammad Imran Tousif Muhammad Imran Tousif ◽  
Naheed Raiz Naheed Raiz ◽  
Mamona Nazir Mamona Nazir ◽  
Mahreen Mukhtar Mahreen Mukhtar ◽  
...  
Keyword(s):  
Natural Products ◽  
Methanol Extract ◽  
High Resolution Mass Spectrometry ◽  
Ethyl Acetate Fraction ◽  
2D Nmr ◽  
Ethyl Carbamate ◽  
Carbamic Acid ◽  
Nmr Analysis ◽  
Nmr Techniques ◽  
Resolution Mass

Silica gel column chromatography of the ethyl acetate fraction of methanol extract of Vincetoxicum stocksii resulted in the separation of three new rarely occurring natural products; [4-(4-(methoxycarbonyl)benzyl)phenyl] carbamic acid (1), bis[di-p-phenylmethane]ethyl carbamate (2), methyl 2-hydroxy-3-(2-hydroxy-5-(3-methylbut-2-enyl)phenyl)-2-(4-hydroxyphenyl) propanoate, stocksiloate(3), along with five known compounds; 1-(4-hydroxy-3-methoxyphenyl)-1,2,3,-propanetriol (4), feruloyl-6-O-β-D-glucopyranoside (5), 4-hydroxy-3,5-dimethoxybenzoic acid (6), apocynin (7) and vincetomine (8). The structures of compounds 1 and 2 were established with help of 1D, 2D-NMR techniques and high resolution mass spectrometry, whereas, compound 3 could only be characterized tentatively by 1D, 2D-NMR techniques. Compounds 1 is new compound while 2 is synthetically known but never been reported from natural source. The known compounds were identified due to 1D NMR analysis and in comparison with the literature values. Compounds 1-3 were found inactive in an anti-urease assay.

Identification of Secondary Metabolites and Antibacterial Activity of Non Polar Fraction from Heterotrigona itama Propolis

2021 ◽  
Vol 2 (1) ◽  
pp. 23-33
Author(s):  
Abdul Aziz ◽  
Veggy Nadya Yuliawan ◽  
Paula Mariana Kustiawan
Keyword(s):  
Antibacterial Activity ◽  
Methanol Extract ◽  
Phenolic Content ◽  
Polar Fraction ◽  
Hexane Fraction ◽  
Diffusion Method ◽  
Total Phenolic ◽  
Phytochemical Analysis ◽  
Phytochemical Content ◽  
Color Changes

Propolis is one of the natural products produced by kelulut bees and is still not widely used. The type of stingless bee that is the prima donna in the community is Heterotrigona itama. This study aims to determine the phytochemical content of the n-hexane fraction of Heterotrigona itama bee propolis collected from Kutai Kartanegara, East Kalimantan. The n-hexane fraction was obtained from the methanol extract of H. itama propolis by the liquid-liquid partition method. After obtaining the n-hexane fraction, the research continued with a qualitative phytochemical test to identify the compound and determine total phenolic. Antibacterial activity was determined by the agar well diffusion method with a serial concentration in Escherichia coli bacteria. Qualitative phytochemical analysis in the form of color changes showed that the n-hexane fraction of H. itama propolis contained flavonoids, alkaloids, saponins, and tannins. Based on the results, the total phenolic content of the n-hexane fraction sample was 490 mgGAE/100 g. It caused the n-hexane fraction to have lower phenolic content than the methanol extract (792 mg GAE100 g). Furthermore, this result indicated that the non-polar fraction was not substantial enough to extracted phenolic compounds. It correlated to the antibacterial activity of the n-hexane fraction, which was very weak (2  mm ± 1.5) at  200µg/mL concentration.

scholarly journals Inhibition of the thrombin–fibrinogen reaction by a macromolecular factor from rat liver

1972 ◽  
Vol 129 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Ragnar Flengsrud ◽  
Bjarne Østerud ◽  
Hans Prydz
Keyword(s):  
Molecular Weight ◽  
Rat Liver ◽  
Gel Electrophoresis ◽  
Competitive Inhibition ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Liver Homogenate ◽  
Kinetic Studies ◽  
Disc Electrophoresis ◽  
Nitrobenzoic Acid

1. The supernatant obtained by centrifugation of a rat liver homogenate at 100000g for 1h contained a heat-labile macromolecular inhibitor of the thrombin–fibrinogen reaction. 2. The inhibitor was purified to electrophoretic homogeneity by repeated preparative polyacrylamide disc electrophoresis. Inhibition was observed with purified inhibitor equivalent to about 1μg of protein/ml. 3. The inhibitor had a pI of 3.50–3.75, a molecular weight (from sodium dodecyl sulphate–polyacrylamide-gel electrophoresis) of 72000±3000 and was inactivated by p-hydroxymercuribenzoate or 5,5′-dithiobis-(2-nitrobenzoic acid). 4. Kinetic studies revealed a non-competitive inhibition, with the inhibitor probably acting on the thrombin–fibrinogen complex.

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