Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak
Flavonoids are natural compounds in plant with wide spectrum of healthbeneficial activities. They exhibit a variety of physico-chemical properties and biological activities but they are normally characterized by low solubility and stability. In order to improve upon these limitations, the enzymat...
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Q Science (General) QD Chemistry Nurul Nadiah , Abd Razak Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak |
description |
Flavonoids are natural compounds in plant with wide spectrum of healthbeneficial
activities. They exhibit a variety of physico-chemical properties and biological
activities but they are normally characterized by low solubility and stability. In order to
improve upon these limitations, the enzymatic acylation of these molecules with fatty
acids is seen as a selective, specific and mild route.
In this study, the synthesis of flavonoid esters catalyzed by lipase was
investigated. Three different flavonoid structures from different classes were selected to
be studied viz. rutin (flavonols), naringin (flavanones) and catechin (flavanols). The
effects of these flavonoid structures on the esterification were investigated with lauric
acid as an acyl donor. The results showed that rutin was the most reactive substrate.
Conversion yields were at 56 % and 47 % for rutin and naringin, respectively. For an
aglycone flavonoid, such as catechin, no glycoside ester formation was observed. Based
on the conversion yield and solubility consideration, rutin was selected for further studies.
For different chain length fatty acid (C12–C16), no significant difference was observed
in terms of yield irrespective of fatty acids used.
Full factorial experimental design (FFD) was used to study the effects of different
process parameters towards the synthesis of rutin laurate. The effects of three selected
operating variables viz. lauric acid concentration (M), temperature (ºC) and enzyme
loading (g) were significant in all cases (P < 0.05). The factors studied showed
temperature has the strongest influence on the ester yield followed by lauric acid
concentration and enzyme loading.
In thermo-kinetic investigation, analysis indicated that lipase-mediated
esterification exhibited Ping-Pong Bi-Bi mechanism with no apparent inhibition by both
substrates. The apparent kinetic of the esterification reaction followed a first-order behavior. The magnitude of glycoside ester formation and the apparent first-order rate
constant, k1’ value increased with temperature. Activation energy, Ea for the esterification
was calculated at 37 kJ mol−1. The esterification process was endothermic with the
enthalpy, H and entropy, S values calculated at +51 kJ mol-1 and +113 J mol-1 K-1,
respectively. Based on the value of Gibbs free energy change, G the esterification
reaction under the conditions studied was predicted to be non-spontaneous below 175 °C
but spontaneous at higher temperatures.
The study also confirmed, through 13C-NMR analysis, the exact location of rutin
esterification. The investigated process biochemistry highlighted important behavior
concerning the biosynthesis of functionalized flavonoid with implication for reactor
design.behavior. The magnitude of glycoside ester formation and the apparent first-order rate
constant, k1’ value increased with temperature. Activation energy, Ea for the esterification
was calculated at 37 kJ mol−1. The esterification process was endothermic with the
enthalpy, H and entropy, S values calculated at +51 kJ mol-1 and +113 J mol-1 K-1,
respectively. Based on the value of Gibbs free energy change, G the esterification
reaction under the conditions studied was predicted to be non-spontaneous below 175 °C
but spontaneous at higher temperatures.
The study also confirmed, through 13C-NMR analysis, the exact location of rutin
esterification. The investigated process biochemistry highlighted important behavior
concerning the biosynthesis of functionalized flavonoid with implication for reactor
design. |
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author |
Nurul Nadiah , Abd Razak |
author_facet |
Nurul Nadiah , Abd Razak |
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Nurul Nadiah , Abd Razak |
title |
Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak |
title_short |
Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak |
title_full |
Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak |
title_fullStr |
Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak |
title_full_unstemmed |
Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak |
title_sort |
kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / nurul nadiah abd razak |
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2015 |
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http://studentsrepo.um.edu.my/7866/4/Thesis_%2528SGR_120077%2529.pdf http://studentsrepo.um.edu.my/7866/ |
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my.um.stud.78662017-11-09T03:55:53Z Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak Nurul Nadiah , Abd Razak Q Science (General) QD Chemistry Flavonoids are natural compounds in plant with wide spectrum of healthbeneficial activities. They exhibit a variety of physico-chemical properties and biological activities but they are normally characterized by low solubility and stability. In order to improve upon these limitations, the enzymatic acylation of these molecules with fatty acids is seen as a selective, specific and mild route. In this study, the synthesis of flavonoid esters catalyzed by lipase was investigated. Three different flavonoid structures from different classes were selected to be studied viz. rutin (flavonols), naringin (flavanones) and catechin (flavanols). The effects of these flavonoid structures on the esterification were investigated with lauric acid as an acyl donor. The results showed that rutin was the most reactive substrate. Conversion yields were at 56 % and 47 % for rutin and naringin, respectively. For an aglycone flavonoid, such as catechin, no glycoside ester formation was observed. Based on the conversion yield and solubility consideration, rutin was selected for further studies. For different chain length fatty acid (C12–C16), no significant difference was observed in terms of yield irrespective of fatty acids used. Full factorial experimental design (FFD) was used to study the effects of different process parameters towards the synthesis of rutin laurate. The effects of three selected operating variables viz. lauric acid concentration (M), temperature (ºC) and enzyme loading (g) were significant in all cases (P < 0.05). The factors studied showed temperature has the strongest influence on the ester yield followed by lauric acid concentration and enzyme loading. In thermo-kinetic investigation, analysis indicated that lipase-mediated esterification exhibited Ping-Pong Bi-Bi mechanism with no apparent inhibition by both substrates. The apparent kinetic of the esterification reaction followed a first-order behavior. The magnitude of glycoside ester formation and the apparent first-order rate constant, k1’ value increased with temperature. Activation energy, Ea for the esterification was calculated at 37 kJ mol−1. The esterification process was endothermic with the enthalpy, H and entropy, S values calculated at +51 kJ mol-1 and +113 J mol-1 K-1, respectively. Based on the value of Gibbs free energy change, G the esterification reaction under the conditions studied was predicted to be non-spontaneous below 175 °C but spontaneous at higher temperatures. The study also confirmed, through 13C-NMR analysis, the exact location of rutin esterification. The investigated process biochemistry highlighted important behavior concerning the biosynthesis of functionalized flavonoid with implication for reactor design.behavior. The magnitude of glycoside ester formation and the apparent first-order rate constant, k1’ value increased with temperature. Activation energy, Ea for the esterification was calculated at 37 kJ mol−1. The esterification process was endothermic with the enthalpy, H and entropy, S values calculated at +51 kJ mol-1 and +113 J mol-1 K-1, respectively. Based on the value of Gibbs free energy change, G the esterification reaction under the conditions studied was predicted to be non-spontaneous below 175 °C but spontaneous at higher temperatures. The study also confirmed, through 13C-NMR analysis, the exact location of rutin esterification. The investigated process biochemistry highlighted important behavior concerning the biosynthesis of functionalized flavonoid with implication for reactor design. 2015 Thesis NonPeerReviewed application/pdf http://studentsrepo.um.edu.my/7866/4/Thesis_%2528SGR_120077%2529.pdf Nurul Nadiah , Abd Razak (2015) Kinetic mechanism and equilibrium thermodynamic of lipase catalyzed synthesis of rutin flavonoid ester / Nurul Nadiah Abd Razak. Masters thesis, University of Malaya. http://studentsrepo.um.edu.my/7866/ |
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