Cholinesterase Inhibitory Effects Research Articles

Phytochemical profile of a blend of black chokeberry and lemon juice with cholinesterase inhibitory effect and antioxidant potential

In this study, black chokeberry concentrate was added (5% w/v) to lemon juice, since previous reports suggested potential health benefits of this blend. The phytochemical composition, antioxidant capacity (scavenging of DPPH, superoxide and hydroxyl radicals, and hypochlorous acid), and inhibitory activity against cholinesterase of the new blend were determined and compared with those of lemon juice and chokeberry in citric acid (5%). The chokeberry concentrate, rich in cyanidin-glycosides, quercetin derivatives, and 3-O-caffeoylquinic acid, and lemon juice, possessing flavones, flavanones, quercetin derivates, and hydroxycinnamic acids, were characterised. The new drink showed a higher antioxidant effect than the chokeberry or lemon controls for all the tested methods, except for hypochlorous acid, in which lemon juice displayed higher activity. Both the lemon juice and chokeberry controls inhibited acetylcholinesterase and butyrylcholinesterase, and this effect was increased in the new mixtures. The results of the different radical scavenging assays indicate that the lemon-black chokeberry (5% w/v) mixture was more antioxidative than the respective controls separately. Moreover, their inhibition of cholinesterase is of interest regarding neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, or senile dementia.

Exploration of cholinesterase and tyrosinase inhibitory, antiprotozoal and antioxidant effects of Buxus sempervirens L. (boxwood)

The petroleum ether, chloroform, ethyl acetate, and methanol extracts of the aerial parts of Buxus sempervirens growing naturally in Turkey were investigated against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) as well as tyrosinase (TYRO) enzymes for their inhibitory activity using ELISA microplate reader. Antiprotozoal activity of the extracts was tested against the parasites; Plasmodium falciparum (malaria) and Trypanosoma brucei rhodesiense (human African trypanosomiasis) at 0.81 and 4.85μg/mL concentrations. As antioxidant activity contributes to antimalarial activity, the extracts were also tested for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, iron-chelating capacity, and ferric-reducing antioxidant power (FRAP). Total phenol and flavonoid contents in the extracts were determined spectrophotometrically. The alkaloid fraction of the chloroform extract afforded two major alkaloids named (+)-buxabenzamidienine (1) and (+)-buxamidine (2). Our results showed that, except for the petroleum ether extract, the extracts displayed high antimalarial and anti-BChE effects as well as quite high iron-chelation capacity. Therefore, we suggest that the active extracts in the antimalarial tests might be showing their effects through the mechanism of BChE inhibition and additionally iron-chelation ability.

Anticholinesterase and antioxidant activities of Savoury (Satureja thymbra L.) with identified major terpenes of the essential oil

Abstract Satureja thymbra was used as a spice in Anatolia and Greece. The essential oil and the methanol extract of Satureja thymbra were evaluated for cholinesterase inhibitory effects against acetylcholinesterase and butyrylcholinesterase which are the chief enzymes of Alzheimer’s disease. The antioxidative effects of the essential oil and the extract were also determined by using β-carotene-linoleic acid, DPPH•-scavenging, ABTS•+-scavenging, and CUPRAC assays. The GC and GC–MS analyses of the essential oil afforded twenty-five compounds. The identified main compounds of the essential oil, carvacrol (34.6%), γ-terpinene (22.9%), p-cymene (13.0%) and thymol (12.8%) were also tested in the same manner. The experimental findings indicated that the compounds, except p-cymene, were active in both activity tests. Moreover, the extract (IC50:13.1 ± 0.23 μg/ml), the oil (IC50:26.7 ± 0.56 μg/ml) and γ-terpinene (IC50:11.9 ± 0.21 μg/ml) exhibited a good lipid peroxidation inhibitory activity. In addition, the possible mechanism of lipid peroxidation inhibitory activity of γ-terpinene was also discussed.

Anticholinesterase and antioxidant effects of the ethanol extract, ethanol fractions and isolated flavonoids from Cistus laurifolius L. leaves

In the current study, the n-hexane, chloroform, ethyl acetate, water, and n-butanol fractions obtained from the main ethanol extract of Cistus laurifolius L. were evaluated for their cholinesterase inhibitory effects against acetyl- (AChE) and butyrylcholinesterase (BChE), at 50, 100, and 200μg/ml, using an ELISA microplate reader. The antioxidative effect of the extract and fractions was also determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelation capacity, and ferric-reducing antioxidant power (FRAP) test systems. Total phenol and flavonoid contents of the extract and fractions were calculated using Folin-Ciocalteau and aluminium chloride reagents. Three flavonoid derivatives; 3-O-methylquercetin (1), 3,7-O-dimethylquercetin (2), and 3,7-O-dimethylkaempferol (3) isolated from the CHCl3 fraction were also tested in the same manner. Our experimental findings indicated that the ethanol extract exerted the highest AChE inhibition (80.07±1.06% at 200μg/ml). The ethyl acetate and n-butanol fractions displayed the best activity against DPPH and FRAP assays.

An in vitro and in silico approach to cholinesterase inhibitory and antioxidant effects of the methanol extract, furanocoumarin fraction, and major coumarins of Angelica officinalis L. fruits

Cholinesterase inhibitory and antioxidant activities of the methanol extract, furanocoumarin fraction, and major coumarins (imperatorin, xanthotoxin, and bergapten) of the fruits of Angelica officinalis L. growing in Poland were determined in the current study. Cholinesterase inhibition was tested against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at 12.5, 25, 50, and 100 μg mL −1 using ELISA microplate reader. Antioxidant activity of the samples was tested by in vitro models including radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), N, N-dimethyl- p-phenylendiamine (DMPD) as well as ferrous ion-chelation capacity, ferric-(FRAP) and phosphomolibdenum-reducing antioxidant power (PRAP) assays at 500, 1000, and 2000 μg mL −1. The extract was found to have strong inhibition against BChE (85.65 ± 1.49%) and low inhibition against AChE (27.49 ± 2.01%) at 100 μg mL −1. Four major coumarins; imperatorin, isoimperatorin, xanthotoxin, and bergapten were identified in the extract by HPLC. Imperatorin (83.98 ± 0.99%), xanthotoxin (88.04 ± 0.83%), and bergapten (86.69 ± 2.56%) displayed strong inhibition towards BChE. Molecular docking studies confirmed potent interactions between BChE and the tested furanocoumarins. The samples did not possess radical scavenging activity against DPPH and DMPD, whereas they possessed a moderate level of FRAP and PRAP at the tested concentrations. To the best of our knowledge, the current work constitutes the first study on cholinesterase inhibitory and antioxidant activities of A. officinalis.

Estimation of Cholinesterase Inhibitory and Antioxidant Effects of the Leaf Extracts of AnatolianFicus caricavar.domesticaand their Total Phenol and Flavonoid Contents

Ficus carica var. domestica Tsch. & Rav. (common fig) is widely grown in Turkey and exported for its edible fruits. In this study, the n-hexane, chloroform, acetone, methanol, n-butanol, and water extracts of the leaves of F. carica var. domestica were screened for their cholinesterase inhibitory and antioxidant activities. Cholinesterase inhibition against acetyl- (AChE) and butyrylcholinesterase (BChE) was measured by the spectrophotometric method of Ellman at concentrations of 25, 50, and 100 microg/mL., while antioxidant activity was tested using three in vitro methods; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, metal-chelation capacity, and ferric-reducing antioxidant power (FRAP). Total phenol and flavonoid contents of the extracts were determined spectrophotometrically. Our results revealed that the n-hexane and acetone extracts exerted a notable inhibition against both AChE (62.9 +/- 0.9% and 50.8 +/- 2.1%, respectively) and BChE (76.9 +/- 2.2% and 45.6 +/- 1.3%, respectively). However, they had low activity in the antioxidant tests. The chloroform extract was found to be the richest in total flavonoid content (252.5 +/- 1.1 mg/g quercetin equivalent), while the n-butanol extract had the highest total phenol amount (85.9 +/- 3.2 mg/g extract gallic acid equivalent).

Neuroprotective effect of seaweeds inhabiting South Indian coastal area (Hare Island, Gulf of Mannar Marine Biosphere Reserve): Cholinesterase inhibitory effect of Hypnea valentiae and Ulva reticulata

Alzheimer's disease (AD) is the most common form of dementia, which is one of the four leading causes of death in developed nations. Until date the only symptomatic treatment for this disease is based on the “cholinergic hypothesis” where the drugs enhance acetylcholine levels in the brain by inhibiting acetylcholinesterase (AChE). In the course for screening cholinesterase inhibitors about eight seaweeds, with wide pharmaceutical applications, were collected from Hare Island, Gulf of Mannar, Marine Biosphere Reserve, Tamil Nadu, India. Inhibitory effect of methanol extract of the seaweeds was studied in vitro by incubating various concentration of the extract with AChE or butyryl cholinesterase (BuChE) and assessing their activities by Ellman's colorimetric method. Kinetic parameters like IC 50, K i and V max were also analyzed. The results showed that of the eight seaweeds screened Hypnea valentiae, Padina gymnospora, Ulva reticulata and Gracilaria edulis exhibited inhibitory activity to AChE with IC 50 value of 2.6, 3.5, 10 and 3 mg/ml respectively, while H. valentiae, Enteromorpha intestinalis, Dictyota dichotoma and U. reticulata showed 50% inhibition to BuChE at concentration 3.9, 7, 6.5 and 10 mg/ml respectively. The inhibitory activities of the seaweed extracts were comparable to the standard drug donepezil. Enzyme kinetic analysis showed that algal extracts exhibited mixed type inhibition (partial noncompetitive inhibition).

Cholinesterase inhibitory effects of the extracts and compounds of Maclura pomifera (Rafin.) Schneider

We have investigated anticholinesterase potential of the methanol extracts from the leaf, wood, flower, twig, and stem bark of the female and male individuals and rhizodermis and fruit from the female tree of Maclura pomifera (Rafin.) Schneider (Moraceae) along with its major isoflavonoids; osajin and pomiferin as well as their semi-synthetic derivatives; iso-osajin and iso-pomiferin. Anticholinesterase activity was determined by Ellman method using ELISA microplate reader. Osajin and pomiferin had a noticeable inhibition of AChE with IC 50 values of 2.239 and 0.096 mM, respectively, while their iso-derivatives were found to display less inhibition towards AChE. The extracts and compounds did not inhibit BChE. The extracts were analyzed for osajin and pomiferin contents by LC–DAD–MS and only the fruits and female flowers contained osajin (fruit: 8.87%, female flowers: 0.19%, w/w) and pomiferin (fruit: 13.6%, female flowers: 0.36%, w/w).

Cholinesterase inhibitory effects of Rhizophora lamarckii, Avicennia officinalis, Sesuvium portulacastrum and Suaeda monica: Mangroves inhabiting an Indian coastal area (Vellar Estuary)

Alzheimer's disease is a progressive neurodegenerative illness accounting for approximately 50% of all types of dementia in elderly people. The only symptomatic treatment proven effective to date is the use of cholinesterase inhibitors to augment surviving cholinergic activity. The purpose of this study is to investigate cholinesterase inhibitory activity of mangroves as an alternative medicine for the treatment of Alzheimer's disease. About nine mangrove plants, which were used as folk medicine in tropical countries, were collected from Parangipettai, Vellar estuary, Tamilnadu, India. Nile Tilapia muscle homogenate was used as source of enzyme. Inhibitory effect of methanolic leaf extract was assessed under in vitro condition by incubating various concentration of the extract with total cholinesterase and butyryl cholinesterase and assessing their residual activities by Ellman's colorimetric method. The results showed that of the nine plants screened Rhizophora lamarckii, Suaeda monica, Avicennia officinalis and Sesuvium portulacastrum showed 50% inhibitory activity to both TChE and BChE at concentrations less than 2 mg/mL when compared to other plant extracts, which was comparable to the standard drug Donepezil. Phytochemical analysis showed the presence of alkaloids in high concentration which might be correlated to its cholinesterase inhibitory activity.

Brunneins A–C, β-Carboline Alkaloids from Cortinarius brunneus

Four beta-carboline alkaloids, brunneins A-C (1-3) and 3-(7-hydroxy-9H-beta-carboline-1-yl)propanoic acid (4), were isolated from fruiting bodies of the agaricoid fungus Cortinarius brunneus. The structures of 1-3 were determined by analysis of NMR and MS data, and the structure of compound 4 was determined by comparison with published data. Brunnein A (1) exhibited very low cholinesterase inhibitory effects and no cytotoxicity.

Comparison of Acute Neurobehavioral and Cholinesterase Inhibitory Effects of N-Methylcarbamates in Rat

While the cholinesterase-inhibiting N-methyl carbamate pesticides have been widely used, there are few studies evaluating direct functional and biochemical consequences of exposure. In the present study of the acute toxicity of seven N-methyl carbamate pesticides, we evaluated the dose-response profiles of cholinesterase (ChE) inhibition in brain and erythrocytes (RBCs) as well as motor activity (both horizontally and vertically directed) and clinical signs of overt toxicity. The chemicals tested were carbaryl, carbofuran, formetanate, methiocarb, methomyl, oxamyl, and propoxur. All were administered orally, and rats were tested in 20-min activity sessions beginning 15 min after dosing; tissues were collected immediately after activity sessions. In general, motor activity was a sensitive measure of ChE inhibition for all these carbamate pesticides, and vertical activity showed the greatest magnitude of effect at the highest doses compared to either horizontal activity or ChE inhibition. Brain and RBC ChE activities were generally affected similarly. Pearson correlation coefficients of within-subject data showed good correlation between the behavioral and biochemical end points, with brain ChE inhibition and horizontal activity showing the highest correlation values. Determination of benchmark dose levels for 10% change in each end point also revealed that these two measures produced the lowest estimates. Thus, motor activity decreases are highly predictive of ChE inhibition for N-methyl carbamates, and vice versa.

Eptastigmine: ten years of pharmacology, toxicology, pharmacokinetic, and clinical studies.

Eptastigmine (heptyl-physostigmine tartrate) is a carbamate derivative of physostigmine in which the carbamoylmethyl group in position 5 of the side chain has been substituted with a carbamoylheptyl group. In vitro and ex vivo results suggest that eptastigmine has a long-lasting reversible brain cholinesterase (i.e., acetylcholinesterase and butyryl-cholinesterase) inhibitory effect. When administered in vivo to rodents by various routes, eptastigmine inhibits cerebral acetylcholinesterases (AChE) and increases acetylcholine (Ach) brain levels by 2500-3000%, depending on the dose. This effect leads to an improvement in the cerebral blood flow in the ischemic brain, excitatory and inhibitory effects on the gastrointestinal tract and to a protection from acute soman and diisopropylfluorophosphate intoxication. Eptastigmine, by either acute or chronic administration, has been found to have memory enhancing effects in different species of normal, aged and lesioned animals. It also restored to normal the age-related increase of EEG power without affecting spontaneous motor activity. Clinical investigations on more than 1500 patients with Alzheimer's disease demonstrated that eptastigmine significantly improved cognitive performance (as assessed by the cognitive subscale of the Alzheimer's Disease Assessment Scale) as compared with placebo. This improvement was most evident in patients with more severe cognitive impairment at the baseline. The relationship between patient performance and average steady-state AChE inhibition was described by an inverted U-shaped dose-response curve. Pharmacokinetic studies have revealed that after oral administration eptastigmine is rapidly distributed to the tissues and readily enters the CNS, where it can be expected to inhibit AChE for a prolonged period. Eptastigmine is generally well tolerated and the majority of adverse events (cholinergic) were mild to moderate in intensity. However, the adverse hematologic (granulocytopenia) effects reported in two studies have resulted in the suspension of further clinical trials.

Steady-state pharmacokinetics of tacrine in long-term treatment of Alzheimer patients.

The pharmacokinetics of the cholinesterase inhibitor tacrine was studied in 5 Alzheimer patients during 12-31 months of treatment. A mean average steady-state concentration in plasma ranging from 1.1 to 30 ng/ml was obtained with doses ranging from 40 to 160 mg of tacrine daily. During treatment with 80 mg daily a maximal plasma concentration of tacrine (8.7 +/- 0.6 ng/ml) was obtained 1.3 +/- 0.2 h after intake of the morning dose. The mean elimination half-life was estimated at 5-7 h and remained unchanged when the tacrine dose was increased. The plasma concentration of tacrine was stable during long-term treatment with tacrine and no tolerance was observed regarding its cholinesterase inhibitory effect. A maximal 40% inhibition of plasma cholinesterase (ChE) activity and 60% inhibition of acetylcholinesterase activity in red blood cells was measured following treatment with the highest dose of 160 mg tacrine daily. A significant correlation was obtained between the plasma concentration of tacrine and the inhibition of ChE activity (p < 0.001). The tacrine concentration in CSF was measured in each patient on 1-3 occasions during the treatment and the ratio CSF/plasma concentration was estimated to be 0.47 +/- 0.09 (n = 11).

Chemical mechanism of the radiation potentiating effects of 2,2-Dimethylaziridine-type antitumor agents

Three 2,2-dimethyl phosphoraziridines, bis(2,2-dimethylaziridinyl)phosphinyl urethane (AB-132, NSC 51325), ethyl bis(2,2-dimethylaziridinyi)phosphinate (AB-163 NSC 108878) and bis(2,2-dimethylaziridinyl)-N-hydroxyurethane (AB-182, NSC 200724) which have shown synergistic antitumor effects in conjunction with X-irradiation, are characterized by their rapid hydrolysis via S N1-mechanism and via the formation of transient 5-membered cyclic intermediates exhibiting phosphorylating activities. It was shown that the formation of the latter correlates with the observed maxima in the cholinesterase inhibitory effects of these compounds. It is proposed that the same intermediate hydrolysis products may block the repair of X-irradiation induced breaks in the DNA strands by phosphorylating their free YOH end groups. Additional mechanisms of the radiation potentiating effects of these compounds (not shown by their C-unsubstituted analogs), involving free radical-ion formation, are currently under investigation.