μM For Acetylcholinesterase Research Articles

Biological and Computational Studies for Dual Cholinesterases Inhibitory Effect of Zerumbone.

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) mediate the degradation of acetylcholine (ACh), a primary neurotransmitter in the brain. Cholinergic deficiency occurs during the progression of Alzheimer’s disease (AD), resulting in widespread cognitive dysfunction and decline. We evaluated the potential effect of a natural cholinesterase inhibitor, zerumbone, using in vitro target enzyme assays, as well as in silico docking and ADMET (absorption, distribution, metabolism, excretion, and toxicity) simulation. Zerumbone showed a predominant cholinesterase inhibitory property with IC50 values of 2.74 ± 0.48 µM and 4.12 ± 0.42 µM for AChE and BChE, respectively; however, the modes of inhibition were different. Computational docking simulation indicated that Van der Waals interactions between zerumbone and both the cholinesterases were the main forces responsible for its inhibitory effects. Furthermore, zerumbone showed the best physicochemical properties for both bioavailability and blood–brain barrier (BBB) permeability. Together, in the present study, zerumbone was clearly identified as a unique dual AChE and BChE inhibitor with high permeability across the BBB, suggesting a strong potential for its physiological benefits and/or pharmacological efficacy in the prevention of AD.

Synthesis, characterization, crystal structure and evaluation of four carbazole-coumarin hybrids as multifunctional agents for the treatment of Alzheimer’s disease

Coupling of two distinct pharmacophores, carbazole and coumarin, endowed with different biological properties, afforded four hybrid compounds. The structures of the carbazole-coumarin hybrids were characterized by FT-IR, NMR, HRMS and single-crystal X-ray diffraction studies. All of these compounds exhibited significant acetylcholinesterase inhibitory activities. Among them, compound 4-((5-(9H-carbazol-9-yl)pentyl)oxy)-2H-chromen-2-one (3d) exhibited the best inhibition activity with IC50 of 3.75 μM for acetylcholinesterase from electric eel and 70.51 μM for human recombinant acetylcholinesterase. Moreover, the compound 7-(3-(9H-carbazol-9-yl propoxy)-4-methyl-2H-chromen-2-one (3a) had the best antioxidant activity. The docking studies demonstrated that compound 3d could interact with both the catalytic active site and the peripheral anionic site of acetylcholinesterase. These attributes imply carbazole-coumarin hybrids as multifunctional agents for the Alzheimer’s disease treatment.

Arachidonoylcholine and Other Unsaturated Long-Chain Acylcholines Are Endogenous Modulators of the Acetylcholine Signaling System.

Cholines acylated with unsaturated fatty acids are a recently discovered family of endogenous lipids. However, the data on the biological activity of acylcholines remain very limited. We hypothesized that acylcholines containing residues of arachidonic (AA-CHOL), oleic (Ol-CHOL), linoleic (Ln-CHOL), and docosahexaenoic (DHA-CHOL) acids act as modulators of the acetylcholine signaling system. In the radioligand binding assay, acylcholines showed inhibition in the micromolar range of both α7 neuronal nAChR overexpressed in GH4C1 cells and muscle type nAChR from Torpedo californica, as well as Lymnaea stagnalis acetylcholine binding protein. Functional response was checked in two cell lines endogenously expressing α7 nAChR. In SH-SY5Y cells, these compounds did not induce Ca2+ rise, but inhibited the acetylcholine-evoked Ca2+ rise with IC50 9 to 12 μM. In the A549 lung cancer cells, where α7 nAChR activation stimulates proliferation, Ol-CHOL, Ln-CHOL, and AA-CHOL dose-dependently decreased cell viability by up to 45%. AA-CHOL inhibited human erythrocyte acetylcholinesterase (AChE) and horse serum butyrylcholinesterase (BChE) by a mixed type mechanism with Ki= 16.7 ± 1.5 μM and αKi= 51.4 ± 4.1 μM for AChE and Ki= 70.5 ± 6.3 μM and αKi= 214 ± 17 μM for BChE, being a weak substrate of the last enzyme only, agrees with molecular docking results. Thus, long-chain unsaturated acylcholines could be viewed as endogenous modulators of the acetylcholine signaling system.

Novel zinc compound with thiosemicarbazone of glyoxylic acid: Synthesis, crystal structure, and bioactivity properties

Reaction of zinc nitrate with thiosemicarbazone of glyoxylic acid (H2GAT) leads to the formation of the new complex that have been characterized by spectroscopic methods. Crystal structure of the compound Zn3C18H34N18O17S6 (1) was determined using single crystal X-ray diffraction methods. Single crystal X-ray measurements showed that the complex crystallized in a triclinic system with the space group P-1. The structure of complex 1 presents distorted octahedral geometry around the zinc ion centre. In the crystal structure, Zn(II) ion is coordinated by two nitrogen, two oxygen and two sulfur atoms from two different thiosemicarbazone of glyoxylic acid and two oxygen atoms from two different water molecules. Thermogravimetry shows four steps of decomposition in the temperature range 225–990 °C. This complex was an inhibitor of butyrylcholinesterase (BChE), cytosolic carbonic anhydride I and II isoforms (hCA I and II) and acetylcholinesterase (AChE) enzymes for complex 1 with Ki values of 0.95 ± 0.10 μM for hCA I, 1.54 ± 0.24 μM for hCA II, 25.98 ± 2.44 μM for BChE, 166.21 ± 13.63 μM for α-glycosidase and 18.53 ± 1.36 μM for AChE, respectively.

Inhibitory Effects of Essential Oil Extracts From Panax ginseng Against β-Secretase and Cholinesterases

Panax ginseng C.A. Meyer is recognized as one of the most important crude drugs in ancient Chinese medicine. Numerous pharmacological studies investigated P. ginseng; however, these studies were limited to ginsenosides, which are typical constituents in P. ginseng. We focused on the essential oil (EO) from P. ginseng as it has a typical aroma. Herein, we report the inhibitory activities of EO against β-secretase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), which were investigated in order to demonstrate the potential of EO as a preventative and therapeutic agent against Alzheimer’s disease (AD). Essential oil (250 µg/mL) showed 41.4% inhibition against β-secretase, 77.4% inhibition against AChE, and 94.1% inhibition against BChE. In addition, spathulenol (8.82%, content % in EO), bicyclogermacrene (6.23%), β-elemene (3.94%), and α-humulene (3.69%) were identified as high content by Gas chromatography mass spectrometry (GC/MS) analysis. Furthermore, β-elemene and α-humulene showed high activity among 3 compounds with 50% inhibitory concentration (IC50) values of 77.2 and 137.3 µM for AChE, and 298.2 and >2000 µM for BChE, respectively. In this report, we showed the inhibitory activity of EO from P. ginseng against β-secretase, AChE, and BChE, and demonstrated that EO could be a candidate to treat AD. This is the first research to report the anti-AD effect of EO and determination of its volatile components. Especially, β-elemene and α-humulene are expected to be highly bio-available compounds due to their small molecular size and lipophilicity. From these results, EO from P. ginseng may be a promising candidate for AD treatment.

Synthesis of potent neuroprotective butenolides based on plant smoke derived 3,4,5-Trimethylfuran-2(5H)-one and 3-methyl-2H-furo[2,3-c]pyrone-2-one

Smoke derived karrikinolide and trimethylbutenolide exerted neuroprotective effects against monoamine oxidase and acetylcholinesterase. Synthesis of potent analogs was achieved. Sulphur substitution in the bicyclic ring structure of KAR1 displayed the most encouraging activity returning IC50 values of 13.75 ± 0.001 μM and 0.03 ± 0.02 μM for monoamine oxidase A and B and 0.08 ± 0.006 μM for acetylcholinesterase. Neuroprotective butenolides may be particularly useful in the treatment of depressive disorders, Alzheimer's and Parkinson's diseases.

Novel eugenol bearing oxypropanolamines: Synthesis, characterization, antibacterial, antidiabetic, and anticholinergic potentials

Five oxypropanol amine derivatives that four of them are novel have been synthesized with high yields and practical methods. in vitro antibacterial susceptibility of Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus strains to synthesized substances were evaluated with agar well-diffusion method by comparison with commercially available drugs. Most of the bacteria were multidrug resistant. It was concluded that these compounds are much more effective than reference drugs. These eugenol bearing oxypropanolamine derivatives were also effective inhibitors against α-glycosidase, cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and acetylcholinesterase (AChE) enzymes with Ki values in the range of 0.80 ± 0.24–3.52 ± 1.01 µM for hCA I, 1.08 ± 0.15–3.64 ± 0.92 µM for hCA II, 5.18 ± 0.84–12.46 ± 2.08 µM for α-glycosidase, and 11.33 ± 2.83–32.81 ± 9.73 µM for AChE, respectively.

Synthesis, biological evaluation and molecular docking of novel pyrazole derivatives as potent carbonic anhydrase and acetylcholinesterase inhibitors

A series of substituted pyrazole compounds (1–8 and 9a, b) were synthesized and their structure was characterized by IR, NMR, and Mass analysis. These obtained novel pyrazole derivatives (1–8 and 9a, b) were emerged as effective inhibitors of the cytosolic carbonic anhydrase I and II isoforms (hCA I and II) and acetylcholinesterase (AChE) enzymes with Ki values in the range of 1.03 ± 0.23–22.65 ± 5.36 µM for hCA I, 1.82 ± 0.30–27.94 ± 4.74 µM for hCA II, and 48.94 ± 9.63–116.05 ± 14.95 µM for AChE, respectively. Docking studies were performed for the most active compounds, 2 and 5, and binding mode between the compounds and the receptors were determined.

Synthesis, crystal structure, and biological evaluation of optically active 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromen-3-carbonitriles: Antiepileptic, antidiabetic, and anticholinergics potentials.

In the presence of chiral organic catalysts, the optically active 4H-chromine was synthesized from the multicomponent condensation of 5,5-dimethylcyclohexane-1,3-dione with malononitrile and methylene-active compound, and the specific angle of rotation of the compounds was determined in the AUTOPOL-III polarimeter and their structures were confirmed by the X-ray spectroscopic analysis method. These optically active 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromen-3-carbonitriles were effective inhibitors of α-glycosidase, the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and acetylcholinesterase (AChE) enzymes with Ki values in the range of 21.33 ± 1.11 to 40.24 ± 10.78 μM for hCA I, 28.91 ± 6.51 to 59.97 ± 15.62 μM for hCA II, 18.16 ± 3.18 to 66.57 ± 1.36 μM for α-glycosidase, and 8.68 ± 0.93 to 102.61 ± 24.96 μM for AChE.

Novel morpholine liganded Pd-based N-heterocyclic carbene complexes: Synthesis, characterization, crystal structure, antidiabetic and anticholinergic properties

This study involves the synthesis of novel N-heterocyclic carbene (NHC)PdX2(morpholine) complexes (1a–i). These Pd-based complexes are synthesized from pyridine enhanced precatalyst preparation stabilization and initiation (PEPPSI) complexes and morpholine. The new complexes were characterized by spectroscopy (IR, 1H and 13C NMR) techniques. Also, the crystal structures of 1b and 1f were obtained by utilizing the single-crystal X-ray diffraction method. The synthesized compounds in this study were investigated for their inhibition action against equin serum butyrylcholinesterase (BChE) and Electrophorus electricus acetylcholinesterase (AChE) as the capability drug aims for Alzheimer’s disease (AD). These novel morpholine liganded Pd-based N-heterocyclic complexes were good inhibitors of BChE, α-glycosidase, cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and AChE, with Ki values in the range of 10.77 ± 1.01–45.86 ± 5.65 µM for hCA I, 25.42 ± 5.18–57.82 ± 3.01 µM for hCA II, 12.26 ± 3.32–50.36 ± 6.19 µM for α-glycosidase, 9.97 ± 1.26–60.75 ± 15.98 µM for BChE, and 10.28 ± 1.55–30.12 ± 3.22 µM for AChE. The inhibition of the α-glycosidase enzyme, an important carbohydrate hydrolyzing catalyst, could be used as one of the efficient methodologies in both treating and preventing diabetes by controlling the suppressing postprandial hyperglycemia and postprandial glucose amounts.

Identification of New Chromenone Derivatives as Cholinesterase Inhibitors and Molecular Docking Studies

Alzheimer's Disease (AD) is the leading cause of dementia among the aging population. This devastating disorder is generally associated with the gradual memory loss, specified by a decrease of acetylcholine level in the cortex hippocampus of the brain due to hyperactivation of cholinesterases (acetylcholinesterase (AChE) and butyrylcholinesterase (BChE)). Therefore, inactivation of AChE and BChE by inhibitors can increase the acetylcholine level and hence may be an encouraging strategy for the treatment of AD and related neurological problems. In this contribution, two series of chromenone-based derivatives were tested by Ellmann's calorimetric method for AChE and BChE inhibition. All the compounds showed inhibitory activity against cholinesterases and some of them exhibited dual inhibition of AChE as well as BChE. The most potent inhibitor of AChE was 2l having an IC50 value of 0.08 ± 0.03 µM, while 3q inhibited the BChE with an IC50 value of 0.04 ± 0.01 µM. In case of dual inhibition, 3h showed an inhibitory concentration of 0.15 ± 0.01 µM for AChE, and 0.09 ± 0.01 µM for BChE. Molecular docking studies were performed to explore the probable binding modes of the most potent dual inhibitors. It can be hypothesized that the inhibitors are able to target cholinesterase pathways and may emerge as a suitable outset for the further development process.

Kinetics and molecular docking of dihydroxanthyletin-type coumarins from Angelica decursiva that inhibit cholinesterase and BACE1.

In the present study, we investigated the anti-Alzheimer's disease (AD) potential of six dihydroxanthyletin-type coumarins, 4'-hydroxy Pd-C-III (1), decursidin (2), Pd-C-I (3), 4'-methoxy Pd-C-I (4), Pd-C-II (5), and Pd-C-III (6) from Angelica decursiva by evaluating their ability to inhibit acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and β-site amyloid precursor protein cleaving enzyme 1 (BACE1). Coumarins 1-6 exhibited dose-dependent inhibition of AChE, BChE, and BACE1. IC50 values were 1.0-4.01µM for AChE, 5.78-13.91µM for BChE, and 1.99-17.34µM for BACE1. Kinetic studies revealed that 1 was noncompetitive inhibitor for AChE, while 2-6 were mixed-type inhibitors of AChE. Compounds 1, 5 and 6 had mixed-type inhibitory effects against BChE; 2 was a competitive inhibitor; and 3 and 4 were noncompetitive inhibitors. Against BACE1, compounds 1, 2, 3, 5 showed mixed-type inhibition and 4, 6 were noncompetitive inhibitors. Molecular docking simulation of the compounds demonstrated negative-binding energies indicating high proximity to the active site and tight binding to the enzyme. These data suggested that the compounds inhibited AChE, BChE, and BACE1, providing a preventive and therapeutic strategy for AD treatment.

The behavior of some chalcones on acetylcholinesterase and carbonic anhydrase activity

Carbonic anhydrase (CA) has a key role in respiration, carbon dioxide and bicarbonate transport. Acetylcholinesterase (AChE) is a serine hydrolase and mostly abundant at neuromuscular junctions and cholinergic brain synapses. Inhibitors of these enzymes could aid in illuminating the role in disease processes. In this study, we separately purified CA I and CA II from human erythrocytes. The purity of the enzymes was showed by SDS-PAGE analysis. We also investigated the inhibition of seven chalcones toward hCA I, hCA II, and AChE. The chalcones were effective inhibitors of the cytosolic CA isoforms (hCA I and hCA II) and AChE with Ki values in the range of 1.83–7.05 μM for hCA I, 0.59–5.50 μM for hCA II, and 0.61–86.11 μM for AChE. All compounds were showed competitive inhibition aganist both enzymes. These compounds can be a potent inhibitor of AChE enzyme and both cytosolic CA isoenzymes which are commonly used in the pharmaceutical and medical industries.

Synthesis and in vitro evaluation of novel N-cycloalkylcarbamates as potential cholinesterase inhibitors

This present paper describes the preparation and characterization of a series of O-substituted N-cycloalkylcarbamate derivatives. These compounds were tested as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). All studied carbamates exhibited moderate inhibitory activity of both cholinesterases with values of IC50 in the range of 36.1–78.6 μM for AChE and 9.8–215.4 μM for BChE, respectively. These values are comparable with those values of inhibition obtained with the established drug rivastigmine. The cytotoxicity of all carbamates was evaluated using standard in vitro test with Jurkat cells. Many of the studied carbamates can be considered as promising compounds for potential medicinal applications with regard to their inhibitory activity as well as negligible cytotoxicity.

Synthesis of novel 5-(aroylhydrazinocarbonyl)escitalopram as cholinesterase inhibitors

A novel series of 5-(aroylhydrazinocarbonyl)escitalopram (58–84) have been designed, synthesized and tested for their inhibitory potential against cholinesterases. 3-Chlorobenzoyl- (71) was found to be the most potent compound of this series having IC50 1.80 ± 0.11 μM for acetylcholinesterase (AChE) inhibition. For the butyrylcholinesterase (BChE) inhibition, 2-bromobenzoyl- (76) was the most active compound of the series with IC50 2.11 ± 0.31 μM. Structure-activity relationship illustrated that mild electron donating groups enhanced enzyme inhibition while electron withdrawing groups reduced the inhibition except o-NO2. However, size and position of the substituents affected enzyme inhibitions. . In docking study of AChE, the ligands 71, 72 and 76 showed the scores of 5874, 5756 and 5666 and ACE of −64.92,-203.25 and −140.29 kcal/mol, respectively. In case of BChE, ligands 71, 76 and 81 depicted high scores 6016, 6150 and 5994 with ACE values −170.91, −256.84 and −235.97 kcal/mol, respectively.

Design, synthesis and evaluation of novel 7-aminoalkyl-substituted flavonoid derivatives with improved cholinesterase inhibitory activities

A novel series of 7-aminoalkyl-substituted flavonoid derivatives 5a–5r were designed, synthesized and evaluated as potential cholinesterase inhibitors. The results showed that most of the synthesized compounds exhibited potent acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities at the micromolar range. Compound 2-(naphthalen-1-yl)-7-(8-(pyrrolidin-1-yl)octyloxy)-4H-chromen-4-one (5q) showed the best inhibitory activity (IC50, 0.64μM for AChE and 0.42μM for BChE) which were better than our previously reported compounds and the commercially available cholinergic agent Rivastigmine. The results from a Lineweaver–Burk plot indicated a mixed-type inhibition for compound 5q with AChE and BChE. Furthermore, molecular modeling study showed that 5q targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Besides, these compounds (5a–5r) did not affect PC12 and HepG2 cell viability at the concentration of 10μM. Consequently, these flavonoid derivatives should be further investigated as multipotent agents for the treatment of Alzheimer’s disease.

Novel biphenyl bis-sulfonamides as acetyl and butyrylcholinesterase inhibitors: Synthesis, biological evaluation and molecular modeling studies

A series of new biphenyl bis-sulfonamide derivatives 2a–3p were synthesized in good to excellent yield (76–98%). The inhibitory potential of the synthesized compounds on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was investigated. Most of the screened compounds showed modest in vitro inhibition for both AChE and BChE. Compared to the reference compound eserine (IC50 0.04±0.0001μM for AChE) and (IC50 0.85±0.0001μM for BChE), the IC50 values of these compounds were ranged from 2.27±0.01 to 123.11±0.04μM for AChE and 7.74±0.07 to <400μM for BuChE. Among the tested compounds, 3p was found to be the most potent against AChE (IC50 2.27±0.01μM), whereas 3g exhibited the highest inhibition for BChE (IC50 7.74±0.07μM). Structure–activity relationship (SAR) of these compounds was developed and elaborated with the help of molecular docking studies.

Synthesis and characterization of 1H-phenanthro[9,10-d]imidazole derivatives as multifunctional agents for treatment of Alzheimer's disease

BackgroundAlzheimer's disease (AD) is a progressive neurodegenerative brain disorder that is characterized by dementia, cognitive impairment, and memory loss. Diverse factors are related to the development of AD, such as increased level of β-amyloid (Aβ), acetylcholine, metal ion deregulation, hyperphosphorylated tau protein, and oxidative stress. MethodsThe following methods were used: organic syntheses of 1H-phenanthro[9,10-d]imidazole derivatives, inhibition of self-mediated and metal-induced Aβ1–42 aggregation, inhibition studies for acetylcholinesterase and butyrylcholinesterase, anti-oxidation activity studies, CD, MTT assay, transmission electron microscopy, dot plot assay, gel electrophoresis, Western blot, and molecular docking studies. ResultsWe synthesized and characterized a new type of 1H-phenanthro[9,10-d]imidazole derivatives as multifunctional agents for AD treatment. Our results showed that most of these derivatives exhibited strong Aβ aggregation inhibitory activity. Compound 9g had 74% Aβ1–42 aggregation inhibitory effect at 10μM concentration with its IC50 value of 6.5μM for self-induced Aβ1–42 aggregation. This compound also showed good inhibition of metal-mediated (Cu2+ and Fe2+) and acetylcholinesterase-induced Aβ1–42 aggregation, as indicated by using thioflavin T assay, transmission electron microscopy, gel electrophoresis, and Western blot. Besides, compound 9g exhibited cholinesterase inhibitory activity, with its IC50 values of 0.86μM and 0.51μM for acetylcholinesterase and butyrylcholinesterase, respectively. In addition, compound 9g showed good anti-oxidation effect with oxygen radical absorbance capacity (ORAC) value of 2.29. ConclusionsCompound 9g was found to be a potent multi-target-directed agent for Alzheimer's disease. General significanceCompound 9g could become a lead compound for further development as a multi-target-directed agent for AD treatment.

Design, synthesis and evaluation of novel 4-dimethylamine flavonoid derivatives as potential multi-functional anti-Alzheimer agents

A series of 4-dimethylamine flavonoid derivatives 5a–5r were designed, synthesized and evaluated as potential multi-functional anti-Alzheimer agents. The results showed that most of the synthesized compounds exhibited high acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity at the micromolar range (IC50, 1.83–33.20μM for AChE and 0.82–11.45μM for BChE). A Lineweaver–Burk plot indicated a mixed-type inhibition for compound 5j with AChE, and molecular modeling study showed that 5j targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Besides, the derivatives showed potent self-induced Aβ aggregation inhibitory activity at 20μM with percentage from 25% to 48%. In addition, some compounds (5j–5q) showed potent oxygen radical absorbance capacity (ORAC) ranging from 1.5- to 2.6-fold of the Trolox value. These compounds should be further investigated as multi-potent agents for the treatment of Alzheimer’s disease.

Isolation and Characterization of Limonoids from Kigelia africana

Two new limonoids, 1-O-deacetyl-2a-methoxykhayanolide (1) and kigelianolide (2), together with deacetylkhayanolide E (3), 1-O-deacetyl-2α-hydroxykhayanolide E (4) and khayanolide B (5) were isolated from the ethyl acetate-soluble fraction of the methanolic extract of Kigelia africana. The structures of these limonoids (1-5) were elucidated by the combination of 1D (1H and 13C NMR) and 2D (HMQC, HMBC and COSY) NMR spectroscopy and mass spectrometry (EIMS, HREIMS), and in comparison with literature data of related compounds. The structure of compound 1 was further confirmed by X-ray crystallography, and the absolute stereochemistry of compounds 1 and 2 was determined by electronic circular dichroism (ECD) spectroscopy. Limonoids 1-5 showed weak inhibitory activities against the enzymes acetylcholinesterase (AChE), butyrycholinesterase (BChE) and lipoxygenase (LOX) in a concentration-dependent manner with IC50 values in the ranges 137.5 - 225.2 μM for AChE, 185.4 - 241.5 μM for BChE and 281.2 - 189.6 μM for LOX