Acetylcholinesterase and monoamine oxidase-B inhibitory activities by ellagic acid derivatives isolated from Castanopsis cuspidata var. sieboldii.

Among 276 herbal extracts, a methanol extract of Castanopsis cuspidata var. sieboldii stems was selected as an experimental source for novel acetylcholinesterase (AChE) inhibitors. Five compounds were isolated from the extract by activity-guided screening, and their inhibitory activities against butyrylcholinesterase (BChE), monoamine oxidases (MAOs), and ß-site amyloid precursor protein cleaving enzyme 1 (BACE-1) were also evaluated. Of these compounds, 4'-O-(α-L-rhamnopyranosyl)-3,3',4-tri-O-methylellagic acid (3) and 3,3',4-tri-O-methylellagic acid (4) effectively inhibited AChE with IC50 values of 10.1 and 10.7 µM, respectively. Ellagic acid (5) inhibited AChE (IC50 = 41.7 µM) less than 3 and 4. In addition, 3 effectively inhibited MAO-B (IC50 = 7.27 µM) followed by 5 (IC50 = 9.21 µM). All five compounds weakly inhibited BChE and BACE-1. Compounds 3, 4, and 5 reversibly and competitively inhibited AChE, and were slightly or non-toxic to MDCK cells. The binding energies of 3 and 4 (- 8.5 and - 9.2 kcal/mol, respectively) for AChE were greater than that of 5 (- 8.3 kcal/mol), and 3 and 4 formed a hydrogen bond with Tyr124 in AChE. These results suggest 3 is a dual-targeting inhibitor of AChE and MAO-B, and that these compounds should be viewed as potential therapeutics for the treatment of Alzheimer's disease.

Pharmacokinetics and pharmacodynamics of levodopa/carbidopa cotherapies for Parkinson's disease.

Introduction: Parkinson's disease is a chronic, neurodegenerative disease entity with heterogeneous features and course. Levodopa is the most efficacious dopamine substituting drug. Particularly, long-term application of oral levodopa/decarboxylase inhibitor formulations sooner or later supports onset of fluctuations of movement. It also shifts levodopa turnover to O-methylation, which impairs human methylation capacity and increases oxidative stress.Areas covered: This narrative review summarizes pharmacokinetic and pharmacodynamic features of available levodopa cotherapies on the basis of a literature search with the terms L-dopa, inhibitors of catechol-O-methyltransferase and monoamine oxidase-B.Expert opinion: Long-term levodopa/dopa decarboxylase inhibitor application with concomitant inhibition of both, catechol-O-methyltransferase and monoamine oxidase-B supports a more continuous dopamine substitution, which ameliorates fluctuations of motor behavior. This triple combination also enhances both, antioxidative defense and methylation capacity. Inhibition of monoamine oxidase-B reduces generation of oxidative stress in the brain. Constraint of catechol-O-methyltransferase reduces homocysteine synthesis due to diminished consumption of methyl groups for levodopa turnover at least in the periphery. An additional nutritional supplementation with methyl group donating and free radical scavenging vitamins is recommendable, when future drugs are developed for long-term levodopa/dopa decarboxylase treated patients. Personalized medicine treatment concepts shall also consider nutritional aspects of Parkinson's disease.

New role for crinamine as a potent, safe and selective inhibitor of human monoamine oxidase B: In vitro and in silico pharmacology and modeling.

ETHNOPHARMACOLOGICAL RELEVANCE: The development of selective inhibitors of monoamine oxidase B (MAO-B) has been essential in treating Parkinson's disease. However, the apparent hepatotoxicity and drug-drug interactions of current inhibitors accentuate the need for the development of novel pharmacotherapies. Crossyne guttata (L.) D. & U. Müll-Doblies is used frequently by Rastafarian bush doctors to treat alcoholism, a disorder which is also accentuated by MAO. OBJECTIVE: The study sought to isolate, identify and characterise the biologically active constituents of C. guttata based on their ability to inhibit the MAO enzymes. MATERIALS AND METHODS: Column chromatography was used to isolate the biologically active alkaloids of C. guttata. The ability of the alkaloids to inhibit the biotransformation of 4-aminoantipyrine by the MAO enzymes was evaluated in vitro. In silico docking was conducted using AutoDock Vina server while the pharmacokinetic properties of the compounds were evaluated using SwissADME. RESULTS: Chromatographic separation of an ethanolic fraction of C. guttata yielded the alkaloids crinamine 1 and epibuphanisine 2. 1 and 2 along with structurally related alkaloids haemanthamine 3 and haemanthidine 4 were evaluated for their ability to inhibit the action of isozymes of MAO in vitro. Alkaloids effected submicromolar IC50 values against MAO-B, the most potent of which being crinamine 1 (0.014 µM) > haemanthidine 4 (0.017 µM) > epibuphanisine 2 (0.039 µM) > haemanthamine 3 (0.112 µM). Binding energies of the alkaloids correlated well with their inhibitory potential with crinamine displaying the best binding efficacy and binding energy score with MAO-B. DISCUSSION AND CONCLUSION: Crinamine and epibuphanisine exhibited potent and selective inhibitory activity towards MAO-B. After comprehensive in silico investigations encompassing robust molecular docking analysis, the drug-like attributes and safety of the alkaloids suggest the crinamine is a potentially safe drug for human application.

Pharmacokinetic drug evaluation of safinamide mesylate for the treatment of mid-to-late stage Parkinson's disease.

INTRODUCTION: Patients with Parkinson's disease suffer from a heterogeneous expression of neurotransmitter deficits. They cause an individual variable expression of motor and non-motor symptoms. Thus, drugs with various mechanisms of actions are suitable to counteract these disease related neurotransmitter alterations. Areas covered: This invited review suggests safinamide as an ideal compound for therapy of Parkinson's disease, as its pharmacological profile includes reversible monoamine oxidase B inhibition, blockage of voltage-dependent sodium channels, modulation of calcium channels and abnormal glutamate release. Safinamide may provide benefits effects on non-motor symptoms in addition to the demonstrated amelioration of motor impairment in levodopa treated patients with Parkinson's disease. Safinamide was well tolerated and safe when administered in dose of 50 or 100 mg daily in pivotal trials. Expert opinion: Clinical handling, safety and tolerability of Safinamide are better than of dopamine agonists or levodopa. Safinamide supplements the existing armamentarium of drugs for Parkinson's disease. Safinamide will help to reduce dosing of levodopa but also of dopamine agonists during long term treatment in patients with Parkinson's disease.

[Other therapeutic strategies]. / Dépression résistante : les autres stratégies thérapeutiques.

Non-selective and irreversible MAOI have become as third or fourth-line strategy for the management of treatment-resistant depression. Non-selective and irreversible MAOI requires careful monitoring of drug interactions and dietary restrictions. Nutritional supplements such as omega-3 have been found to produce beneficial effects in the management of treatment-resistant depression when administered in combination with the ongoing antidepressant treatment. The glutamate antagonist ketamine has been found to produce beneficial effects in the management of treatment-resistant depression while administered alone. Dopamine and/or norepinephrine agonists, such as methylphenidate, modafinil or pramipexole, have been found to produce beneficial effects in the management of treatment-resistant depression when administered in combination with the ongoing antidepressant treatment.

Efectos secundarios de los antidepresivos / Adverse events of antidepressants

No disponible

No disponible

Inhibition of rat brain monoamine oxidase activities by psoralen and isopsoralen: implications for the treatment of affective disorders.

Psoralen and isopsoralen, furocoumarins isolated from the plant Psoralea corylifolia L., were demonstrated to exhibit in vitro inhibitory actions on monoamine oxidase (MAO) activities in rat brain mitochondria, preferentially inhibiting MAO-A activity over MAO-B activity. This inhibition of enzyme activities was found to be dose-dependent and reversible. For MAO-A, the IC50 values are 15.2 +/- 1.3 microM psoralen and 9.0 +/- 0.6 microM isopsoralen. For MAO-B, the IC50 values are 61.8 +/- 4.3 microM psoralen and 12.8 +/- 0.5 microM isopsoralen. Lineweaver-Burk transformation of the inhibition data indicates that inhibition by both psoralen and isopsoralen is non-competitive for MAO-A. The Ki values were calculated to be 14.0 microM for psoralen and 6.5 microM for isopsoralen. On the other hand, inhibition by both psoralen and isopsoralen is competitive for MAO-B. The Ki values were calculated to be 58.1 microM for psoralen and 10.8 microM for isopsoralen. These inhibitory actions of psoralen and isopsoralen on rat brain mitochondrial MAO activities are discussed in relation to their toxicities and their potential applications to treat affective disorders.

Toxicokinetic evaluation of a selegiline transdermal system in the dog.

The toxicology and toxicokinetics of a selegiline transdermal system (STS) were evaluated in a 3 month dog study of daily 24 h applications of placebo 4, 8, or 12 STSs in 32 male and 32 female beagle dogs. Each STS delivered approximately 5 mg selegiline over 24 h. No drug-related signs of toxicity were noted in any group with respect to clinical observations, dermal effects, body weight, food consumption, hematology, urinalysis data, or ophthalmoscopic or electrocardiographic examinations. Clinical chemistry data revealed no consistent adverse effects except for an increase in alanine aminotransferase in dogs receiving 8 and 12 STSs. Histological evaluation of tissues revealed the presence of pigment in the Kupffer cells of dogs treated with 8 and 12 STSs. There were no pathology findings suggestive of hemolysis or cholestasis. The no-effect level (NOEL) was 4 STSs (2.9 mg kg-1 d-1). There were no degenerative or life-threatening toxic effects up to 12 STSs (8.5 mg kg-1 d-1). Gender-related differences in steady-state plasma levels were not observed. Steady-state plasma concentrations were similar to maximum plasma concentrations obtained in single-dose studies, suggesting that drug accumulation was not evident. Simulation of systemic exposure following oral administration of 16.8 mg kg-1 d-1 from previous toxicology studies indicated that selegiline exposure following 12 STSs is sixfold greater while N-desmethylselegiline, L-amphetamine, and L-methamphetamine exposure is 0.5, 0.15, and 0.14 times the exposure in the oral study. The threefold difference in NOEL between oral and transdermal studies in the dog (0.8 versus 2.9 mg kg-1 d-1) is probably related to greater L-amphetamine and L-methamphetamine exposure following oral administration. The reduction in metabolite formation, relative exposure of selegiline in the dog at the NOEL compared to oral toxicology studies, and margin of safety provided, given that the expected clinical dose is less than the dosage of oral Eldepryl (0.15 mg kg-1 d-1), documents the safety of the selegiline drug substance and indicates that additional toxicologic findings with the STS may not be expected.

Are metabolites of l-deprenyl (selegiline) useful or harmful? Indications from preclinical research.

A frequent topic of controversy has been whether metabolism of l-deprenyl (selegiline) to active metabolites is a detriment to clinical use. This paper reviews possible roles of the metabolites of l-deprenyl in producing unwanted adverse side effects or in augmenting or mediating its clinically useful actions. Levels of l-amphetamine and l-methamphetamine likely to be reached, even with excessive intake of l-deprenyl, would be unlikely to produce neurotoxicity and there is no preclinical or clinical evidence of abuse liability of l-deprenyl. In contrast, there is evidence that l-amphetamine and l-methamphetamine have some qualitatively different actions than their d-isomer counterparts on EEG and cognitive functioning which might result in beneficial clinical effects and complement beneficial clinical actions of l-deprenyl itself.

123I-labeling and evaluation of Ro 43-0463, a SPET tracer for MAO-B imaging.

Using the copper assisted halogen exchange the MAO-B inhibitor Ro 43-0463, N-(2-aminoethyl)-5-iodo-2-pyridinecarboxamide, was labelled with 123I as well as with 125I to allow in vitro and in vivo investigations including SPET with healthy volunteers. Ro 43-0463 is known to inhibit reversibly and specifically MAO-B, having an IC50 of 3 x 10(-8) Mol/L. The labeling in the presence of CuSO4 and ascorbic acid was optimised, varying time (30 to 105 min), precursor concentration (1-3.5 mg) and temperature (130-200 degrees C). The labeling yield ranged between 60 and 70%. Purification was achieved with Lichrosorb RP-18 (5 micron, 250 x 8 mm) and 1.5 mL/min 0.36 M H3PO4/EtOH 97/3 [0.01 M (NH4)2HPO4]. After neutralisation and sterile filtration the final activity concentration ranged between 18.5 and 37 MBq/mL. Biodistribution studies showed a brain to blood ratio greater than 1 within 1 h p.i. The main radiation burden calculated from these animal data is to alimentary and excretory organs and the ovaries. Autoradiography was performed using rat brain slices and 5 nM [125I]Ro 43-0463 in TRIS-buffer pH 7.4 for 90 min at 20 degrees C. Its radioactivity pattern corresponds to the known distribution of MAO-B in the rat brain. By displacement with L-deprneyl the highly specific binding of R0 43-0463 was proven in vitro. SPECT studies with normal volunteers corresponded with the pattern found in autoradiography.