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Abstract Background Geographic atrophy (GA) is a significant cause of vision loss in patients with age-related macular degeneration (AMD). Current treatments are limited to anti-complement drugs, which have limited efficacy to delay progression with significant risk of complications. Levodopa (L-DOPA) is a byproduct of melanin synthesis that is associated with reduced development of neovascular AMD. In this study, we determined if L-DOPA was associated with a reduced likelihood of new-onset GA. Methods We performed a retrospective analysis in the Vestrum Health Retina Database. We included eyes with non-neovascular AMD without GA and 1–5 years of follow-up. Eyes were divided into two groups. Exposed to L-DOPA before or on the date of non-neovascular AMD without GA diagnosis, and eyes not exposed to L-DOPA. We extracted age, sex, AREDS2 status, dry AMD stage, smoking history, and conversion rate to GA at years 1 through 5. Propensity score matching was used to match L-DOPA and control groups. Cox proportional hazard regression, adjusting for age, sex, AMD severity, AREDS2 use, smoking status, and L-DOPA use was employed to calculate hazard ratios for new-onset GA detection. Results We identified 112,089 control and 844 L-DOPA exposed eyes with non-neovascular AMD without GA. After propensity score matching, 2532 control and 844 L-DOPA exposed eyes remained that were well-matched for age, sex, AMD severity, AREDS2 use, and smoking status. We found that L-DOPA exposure was associated with a significantly reduced likelihood (HR = 0.68, 95% CI: 0.48–0.95, P = 0.025) of new-onset GA detection. Conclusion L-DOPA use was associated with reduced detection of new-onset GA.

Abstract Despite the intensive research on gut microbiome-associated diseases over the past 20 years, pharmacological methods for effectively eliminating pathobionts remain unsatisfactory. This study investigated the therapeutic potential of bacteriophages against Enterococcus faecalis, in which bacterial tyrosine decarboxylase (TDC) converts orally administered levodopa (L-DOPA) to dopamine, in an MPTP mouse model of Parkinson’s disease (PD). E. faecalis bacteriophages PBEF62, PBEF66, and PBEF67 (4 × 1010 PFU total/200 µl/day), and E. faecalis cells (2 × 109 CFU/200 µl/day) were orally administered at 2-h intervals before every MPTP (i.p.) and/or L-DOPA (p.o.) treatments for 13 days. The relative abundances of E. faecalis cells and bacteriophages in the feces peaked at 4 and 12 h after administration and gradually decreased by 12 and 48 h, respectively. While the administration of E. faecalis cells eliminated the beneficial effect of L-DOPA on MPTP-induced behavioral deficits, as assessed by cylinder and rotarod tests, the co-administration of bacteriophages with bacterial cells restored this effect. The modulating effects of L-DOPA, E. faecalis, and bacteriophages on PD behavior were closely associated with choline acetyltransferase expression levels in the striatum but not with tyrosine hydroxylase in the substantia nigra of each group. Recurrence and extinction of PD behaviors following treatment with E. faecalis and/or bacteriophages were also coincident with the dopamine levels in the blood and brain tissues of PD mice. The effectiveness of L-DOPA was restored after the three types of E. faecalis bacteriophages selectively eliminated E. faecalis cells, along with the TDC gene copies and transcripts responsible for converting L-DOPA to dopamine in the gastrointestinal tract. In conclusion, a combination of bacteriophages PBEF62, PBEF66, and PBEF67 targeting E. faecalis demonstrates potential as a valuable supplement to L-DOPA therapy for PD.

ABSTRACT Diabetic striatopathy, a rare hyperglycemia complication, is characterized by chorea/ballism and striatal anomalies on neuroimaging, usually managed with glycemic control and haloperidol. However, practical strategies for haloperidol‐resistant cases are scarce. We describe a 76‐year‐old Japanese woman with diabetic striatopathy who initially presented with polydipsia, polyuria, and lower‐extremity weakness. Despite pronounced hyperglycemia (725 mg/dL), her blood glucose levels were reduced through saline infusion and intravenous insulin. Subsequently, she developed whole‐body ballism concomitant with striatal hyperintensity on T1‐weighted magnetic resonance imaging, which initially responded to haloperidol. Upon discontinuation of haloperidol, her symptoms relapsed and did not improve with the reintroduction of haloperidol. Dopamine transporter single photon emission computed tomography revealed diminished bilateral striatal uptake, suggesting presynaptic dopaminergic dysfunction. This finding prompted the initiation of L‐dopa, which significantly improved her symptoms. This case underlines the need to consider presynaptic dopaminergic dysfunction in diabetic striatopathy patients unresponsive to standard treatments, highlighting the effectiveness of L‐dopa in such scenarios.

Abstract Parkinson’s disease (PD) is a chronic neurodegenerative case. As the disease progresses, the response time to doses of levodopa (L-Dopa) becomes shorter and the effects of the drug are severely limited by some undesirable side effects such as the ‘on–off’ phenomenon. In several diseases, including Parkinson’s, nanoparticles can deliver antioxidant compounds that reduce oxidative stress. This study evaluates and compares the neuroprotective effects of L-Dopa-modified zinc nanoparticles (ZnNPs) in the 6-hydroxydopamine (6-OHDA)-induced PD rat model. For this purpose, the synthesis of NPs was carried out. Scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectrophotometer were used for characterization. The rats were randomized into 9 experimental groups: control, lesion group (6-OHDA), 6-OHDA + 5 mg/kg L-Dopa, 6-OHDA + 10 mg/kg L-Dopa, 6-OHDA + 20 mg/kg L-Dopa, 6-OHDA + 20 mg/kg ZnNPs, 6-OHDA + 40 mg/kg ZnNPs, 6-OHDA + 30 mg/kg ZnNPs + L-Dopa, and 6-OHDA + 60 mg/kg ZnNPs + L-Dopa. Behavioral tests were performed on all groups 14 days after treatment. Phosphatase and tensin homolog, Excitatory amino acid transporter 1/2, and Glutamine synthetase gene analyses were performed on brain samples taken immediately after the tests. In addition, histological and immunohistochemical methods were used to determine the general structure and properties of the tissues. We obtained important findings that L-Dopa-modified ZnNPs increased the activity of glutamate transporters. Our experiment showed that glutamate increases neuronal cell vitality and improves behavioral performance. Therefore, L-Dopa-modified ZnNPs can be used to prevent neurotoxicity. According to what we found, results show that L-Dopa-modified ZnNPs will lend to the effective avoidance and therapy of PD.

Abstract Background Chronic kidney disease (CKD) and hypertension are chronic diseases affecting a large portion of the population frequently coexistent and interdependent. The inability to produce/use adequate renal dopamine may contribute to the development of hypertension and renal dysfunction. The heterodimeric amino acid transporter LAT2/4F2hc (SLC7A8/SLC3A2 genes) promotes the uptake of L-DOPA, the natural precursor of dopamine. We examined the plausibility that SLC7A8/SLC3A2 gene polymorphisms may contribute to hypertensive CKD by affecting the L-DOPA uptake. Methods 421 subjects (203 men and 218 women, mean age of 78.9 ± 9.6 years) were recruited and divided in four groups according to presence/absence of CKD, defined as reduced estimated glomerular filtration rate (eGFR

ABSTRACT Introduction In childhood, growth hormone (GH) deficiency (GHD) diagnosis is based on auxological assessment and biochemical provocative tests, whose reliability remains disputed. Recently, several papers have been published on standardising the duration of some tests. The aim of our study was to analyse the possible length reduction of the L‐DOPA provocative test. Methods We retrospectively investigated the response of GH to L‐DOPA in 256 children, analysing 267 tests (some patients were retested over time for the persistence of severe auxopathy). We studied the same data considering GH peak threshold both at 8 ng/mL (Italian GHD cut‐off) and at 10 ng/mL (international cut‐off). Based on stimulation tests, patients were divided into two groups: GHD and no‐GHD short children. We described the results in the whole population and then clustering for gender and pubertal stage. We termed as index the test stopped at 90 min. Results The GH peak after L‐DOPA mostly occurred at 60 min. The sensitivity of the index test was the highest, while the specificity was slightly higher using the 8 ng/mL threshold (specificity = 0.68; 95% CI 0.60–0.76) then using the 10 ng/mL threshold (specificity = 0.56; 95% CI 0.47–0.65) at 90 min. The two ROC curves showed moderate performance of the test at 90 min. While the negative predictive value was 100% in both tests, the positive predictive value was slightly better with 10 ng/mL cut‐off. Considering the two groups established by GHD definition and placing a GH threshold at 10 ng/mL, stopping L‐DOPA test time at 90 min would have changed the test result and subsequentially patient's classification in 3/267 of the analysed tests (1.1%), while with the Italian GH threshold value at 8 ng/mL in 7/267 of the tests (2.6%). Conclusions Our research shows that omitting 120‐min time reduces L‐DOPA test specificity, especially with GHD cut‐off at 10 ng/mL.

Abstract Dopamine plays important roles in cognitive function and inflammation and therefore is involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD). Drugs that increase or maintain dopamine levels in the brain could be a therapeutic strategy for AD. However, the effects of dopamine and its precursor levodopa (L-DOPA) on Aβ/tau pathology in vivo and the underlying molecular mechanisms have not been studied in detail. Here, we investigated whether L-DOPA treatment alters neuroinflammation, Aβ pathology, and tau phosphorylation in 5xFAD mice, a model of AD. We found that L-DOPA administration significantly reduced microgliosis and astrogliosis in 5xFAD mice. In addition, L-DOPA treatment significantly decreased Aβ plaque number by upregulating NEP and ADAM17 levels in 5xFAD mice. However, L-DOPA-treated 5xFAD mice did not exhibit changes in tau hyperphosphorylation or tau kinase levels. These data suggest that L-DOPA alleviates neuroinflammatory responses and Aβ pathology but not tau pathology in this mouse model of AD.

Parkinson's disease is caused by a selective vulnerability and cell loss of dopaminergic neurons of the Substantia Nigra pars compacta and, consequently, striatal dopamine depletion. In Parkinson's disease therapy, dopamine loss is counteracted by the administration of L-DOPA, which is initially effective in ameliorating motor symptoms, but over time leads to a burdening side effect of uncontrollable jerky movements, termed L-DOPA-induced dyskinesia. To date, no efficient treatment for dyskinesia exists. The dopaminergic and serotonergic systems are intrinsically linked, and in recent years, a role has been established for pre-synaptic 5-HT1a/b receptors in L-DOPA-induced dyskinesia. We hypothesized that post-synaptic serotonin receptors may have a role and investigated the effect of modulation of 5-HT4 receptor on motor symptoms and L-DOPA-induced dyskinesia in the unilateral 6-OHDA mouse model of Parkinson's disease. Administration of RS 67333, a 5-HT4 receptor partial agonist, reduces L-DOPA-induced dyskinesia without altering L-DOPA's pro-kinetic effect. In the dorsolateral striatum, we find 5-HT4 receptor to be predominantly expressed in D2R-containing medium spiny neurons, and its expression is altered by dopamine depletion and L-DOPA treatment. We further show that 5-HT4 receptor agonism not only reduces L-DOPA-induced dyskinesia, but also enhances the activation of the cAMP-PKA pathway in striatopallidal medium spiny neurons. Taken together, our findings suggest that agonism of the post-synaptic serotonin receptor 5-HT4 may be a novel therapeutic approach to reduce L-DOPA-induced dyskinesia.

Developing efficient bioprocesses requires selecting the best biosynthetic pathways, which can be challenging and time-consuming due to the vast amount of data available in databases and literature. The extension of the shikimate pathway for the biosynthesis of commercially attractive molecules often involves promiscuous enzymes or lacks well-established routes. To address these challenges, we developed a computational workflow integrating enumeration/retrosynthesis algorithms, a toolbox for pathway analysis, enzyme selection tools, and a gene discovery pipeline, supported by manual curation and literature review. Our focus has been on implementing biosynthetic pathways for tyrosine-derived compounds, specifically L-3,4-dihydroxyphenylalanine (L-DOPA) and dopamine, with significant applications in health and nutrition. We selected one pathway to produce L-DOPA and two different pathways for dopamine–one already described in the literature and a novel pathway. Our goal was either to identify the most suitable gene candidates for expression in Escherichia coli for the known pathways or to discover innovative pathways. Although not all implemented pathways resulted in the accumulation of target compounds, in our shake-flask experiments we achieved a maximum L-DOPA titer of 0.71 g/L and dopamine titers of 0.29 and 0.21 g/L for known and novel pathways, respectively. In the case of L-DOPA, we utilized, for the first time, a mutant version of tyrosinase from Ralstonia solanacearum. Production of dopamine via the known biosynthesis route was accomplished by coupling the L-DOPA pathway with the expression of DOPA decarboxylase from Pseudomonas putida, resulting in a unique biosynthetic pathway never reported in literature before. In the context of the novel pathway, dopamine was produced using tyramine as the intermediate compound. To achieve this, tyrosine was initially converted into tyramine by expressing TDC from Levilactobacillus brevis, which, in turn, was converted into dopamine through the action of the enzyme encoded by ppoMP from Mucuna pruriens. This marks the first time that an alternative biosynthetic pathway for dopamine has been validated in microbes. These findings underscore the effectiveness of our computational workflow in facilitating pathway enumeration and selection, offering the potential to uncover novel biosynthetic routes, thus paving the way for other target compounds of biotechnological interest.

Mitochondrial dysmorphology/dysfunction follow global cerebral ischemia-reperfusion (GCI/R) injury, leading to neuronal death. Our previous researches demonstrated that Levodopa (L-DOPA) improves learning and memory impairment in GCI/R rats by increasing synaptic plasticity of hippocampal neurons. This study investigates if L-DOPA, used in Parkinson's disease treatment, alleviates GCI/R-induced cell death by enhancing mitochondrial quality. Metabolomics and transcriptomic results showed that GCI/R damage affected the Tricarboxylic acid (TCA) cycle in the hippocampus. The results of this study show that L-DOPA stabilized mitochondrial membrane potential and ultrastructure in hippocampus of GCI/R rats, increased dopamine level in hippocampus, decreased succinic acid level, and stabilized Ca2+ level in CA1 subregion of hippocampus. As a precursor of dopamine, L-DOPA is presumed to improves mitochondrial function in hippocampus of GCI/R rats. However, dopamine cannot cross the blood-brain barrier, so L-DOPA is used in clinical therapy to supplement dopamine. In this investigation, OGD/R models were established in isolated mouse hippocampal neurons (HT22) and primary rat hippocampal neurons. Notably, dopamine exhibited a multifaceted impact, demonstrating inhibition of mitochondrial reactive oxygen species (mitoROS) production, stabilization of mitochondrial membrane potential and Ca2+ level, facilitation of TCA circulation, promotion of aerobic respiratory metabolism, and downregulation of succinic acid-related gene expression. Consistency between in vitro and in vivo results underscores dopamine's significant neuroprotective role in mitigating mitochondrial dysfunction following global cerebral hypoxia and ischemia injury. Supplement dopamine may represent a promising therapy to the cognitive impairment caused by GCI/R injury.

Background and Aim: In healthy people, dopamine stimulates ghrelin secretion. The level of dopamine release and ghrelin is lower in the patients with polycystic ovary syndrome (PCOS). In the present study,we investigated the effects of doplamin and L-dopa on relative gene expression of ghrelin in PCOS model rats. Materials and Methods: In the first step of the study, PCOS was induced in 25 female Wistar rat (Rattus norvegicus) by injection of estradiol. Then, the rats received saline, dopamine (5µg), L-dopa (5µg) or simultaneous injections of sulpride (10µg/kg), SCH23390 hydrochloride (10µg/kg) and dopamine or L-dopa respectively via third cerebral ventricular. In the second part of the study, 15 PCOS rats received saline L-dopa (100mg/kg) or dopamine (50mg/kg) intraperitoneally. Hypothalamic and ovarian samples were dissected. Mean relative ghrelin gene expression was determined by real- time-PCR method. Results: Mean relative gene expression of ghrelin significantly decreased in the hypothalamus and ovary of the rats with PCOS compared to those in the intact rats. Intraventricular injection of dopamine or L-dopa significantly increased the hypothalamic ghrelin gene expression in comparison to that in the rats in the PCOS group. Dopamine or L-dopa did not significantly increase the gene expression of ovarian ghrelin in comparison to that in PCOS group. Injections of sulpride and SCH23390 significantly blocked the stimulatory effects of dopamine or L-dopa on the ghrelin gene expression in hypothalamus compared to those in the dopamine or L-dopa group. Conclusion: The dopaminergic pathway may be involved in increasing ghrelin gene expresion extremely via hypothamic level in PCOS condition.

The use of phosphodiesterase inhibitors in the treatment of Parkinson’s disease is currently widely discussed. The study aimed to investigate the impact of acute and chronic treatment with the phosphodiesterase 5 inhibitor, sildenafil, at low and moderate doses of 2 mg/kg and 6 mg/kg, and L-DOPA (12.5 mg/kg), alone or in combination, on asymmetric behavior and dopamine (DA) and serotonin metabolism in the striatum and substantia nigra of unilaterally 6-OHDA-lesioned rats. Acute administration of sildenafil at both tested doses jointly with L-DOPA significantly increased the number of contralateral rotations during a 2 h measurement compared to L-DOPA alone. The effect of a lower dose of sildenafil combined with L-DOPA was much greater in the second hour of measurement. However, the acute combined administration of a higher dose of sildenafil with L-DOPA resulted in an immediate and much stronger increase in the number of contralateral rotations compared to L-DOPA alone, already visible in the first hour of measurement. Interestingly, the chronic combined administration of 2 mg/kg of sildenafil and L-DOPA significantly reduced the number of contralateral rotations, especially during the first hour of measurement, compared to the long-term treatment with L-DOPA alone. Such an effect was not observed after the long-term combined treatment of a higher dose of sildenafil and L-DOPA compared to L-DOPA alone. The concentration of DA in the ipsilateral striatum and substantia nigra after the last combined chronic dose of sildenafil (2 or 6 mg/kg) and L-DOPA (12.5 mg/kg) was significantly higher than after L-DOPA alone. In spite of much stronger increases in the DA concentration in the ipsilateral striatum and substantia nigra, the number of contralateral rotations was reduced in the group of rats treated with the combination of 2 mg/kg sildenafil and L-DOPA compared to the group receiving L-DOPA alone. Moreover, the combined treatment with a low dose of sildenafil and L-DOPA had an opposite effect on DA catabolism, as assessed by DOPAC/DA and HVA/DA indexes, and these indexes were reduced in the ipsilateral striatum but increased in the contralateral striatum and substantia nigra compared to the treatment with L-DOPA alone. The results of the present study show that the addition of a low dose of a PDE5 inhibitor to the standard L-DOPA therapy differently modulates rotational behavior, the tissue DA concentration and its catabolism in the striatum and substantia nigra.

Underutilized legume comprises vital nutrients with a higher proportion of protein (23-43 %) equal to soybean, and lima bean and greater than chickpea and green pea. In addition, it has a good calorific value, carbohydrates, vitamins, and minerals. The presence of bioactive components such as polyphenols and flavonoids increases the market demand in pharmacological industries at the global level. It exhibits several pharmacological properties like antioxidant, anti-inflammatory, anti-diabetic, antimicrobial, and antihypertensive. It has a higher concentration of antinutritional compounds like l-DOPA, phytates, tannin, oxalate, hydrogen cyanide, and trypsin inhibitors. These barriers prevent the consumption of velvet beans, and they can be reduced by both conventional and modern methods. The methods include dehulling, boiling, soaking, cooking, roasting, toasting, fermentation, sonication, and acid and alkali treatment. Each method has a distinct effect on the method of removal of antinutrients and it has an impact on its reduction percentage. The degree of modification in the physicochemical composition does fall under a considerable limit and doesn't affect the actual nutritional composition of the mucuna seeds. It is considered an alternative protein source to animal protein, hence extraction of protein from velvet beans has a better scope to isolate and concentrate protein and its peptides. This flour has been utilized in food formulations like bread, crackers, food mix, beverage mix, mucuna milk, and traditional foods like moin moin, chapatti, and mash. The major constraint of the utilization in the food industry is due to the presence of antinutrients and their removal and depletion by various treatments was focussed. It can replace the source of animal protein, fulfill the protein insufficiency of the population and increase food security.

Abstract The traditional method of monitoring the oxidation and reduction of biomedical materials usually relies on electrochemical (EC) measurement techniques. Here, we demonstrate a surface plasmon resonance (SPR) method to monitor the oxidation process. Using levodopa L-dopa as the target analyte, a nanohole sensing plate is embedded in the EC electrode to enhance the oxidation signal and generate SPR. Cyclic voltammetry (CV) measurement was first conducted to understand the baseline of EC response of L-Dopa. Then, the redox reactions were simultaneously monitored through SPR measurements during the CV voltage scan. The results showed that the limit of detection using traditional CV reached 1.47 μM while using EC-SPR, the limit of detection improved to 1.23 μM. Most importantly, we found a strong correlation between CV current profiles and the SPR reflection spectra. Our results facilitate detecting electrochemical reactions using an optical probing method.

Vicia faba L. is a leguminous plant with seeds rich in nutritional compounds, such as polyphenols and L-dopa, a dopamine precursor and first-line treatment for Parkinson’s symptoms. Recently, its by-products have been revalued as a sustainable source of bioactive compounds. In this study, aqueous extracts of Lucan broad bean pod valves (BPs) were characterized to evaluate their potential use as adjuvants in severe Parkinson’s disease. L-dopa content, quantified by LC-UV, was much higher in BPs than in seeds (28.65 mg/g dw compared to 0.76 mg/g dw). In addition, vicine and convicine, the metabolites responsible for favism, were not detected in pods. LC-ESI/LTQ-Orbitrap/MS2 allowed the identification of the major polyphenolic compounds, including quercetin and catechin equivalents, that could ensure neuroprotection in Parkinson’s disease. ESI(±)-FT-ICR MS was used to build 2D van Krevelen diagrams; polyphenolic compounds and carbohydrates were the most representative classes. The neuroprotective activity of the extracts after MPP+-induced neurotoxicity in SH-SY5Y cells was also investigated. BP extracts were more effective than synthetic L-dopa, even at concentrations up to 100 µg/mL, due to the occurrence of antioxidants able to prevent oxidative stress. The stability and antioxidant component of the extracts were then emphasized by using naturally acidic solutions of Punica granatum L., Ribes rubrum L., and gooseberry (Phyllanthus emblica L.) as extraction solvents.

The genus Mucuna is a potential protein source, but it has been underutilized due to the presence of antinutritional factors, especially L-DOPA. Solid-state fermentation with lactic acid bacteria could be an effective and simple method for reducing these antinutritional factors while simultaneously enriching the protein content. In this work, an experimental analysis identified the variables with the greatest influence on the solid-state fermentation of Mucuna deeringiana. In general, we observed a decrease in pH due to the production of and increase in lactic acid, resulting in a 91% (6.40 to 0.55 g/100 g sample) reduction in L-DOPA, 51% decrease in phenolic compounds (11.65 to 5.70 g/100 g sample), 97% decrease in tannins (1.26 to 0.04 g/100 g sample), and the antioxidant capacity of the fermented flour was 97%, with an increase in protein content of 12%. Furthermore, it demonstrated greater stability over 24 days compared to the control samples, which remained stable for only 3 days. These results suggest that the bacterium has a positive effect on the production of lactic acid, and the nutritional composition can be enhanced by reducing antinutritional factors, especially L-DOPA, that limit the use of this legume. This process proves to be a cost-effective and sustainable method for developing nutritious feed products derived from Mucuna flours.

Graphene is a promising biomaterial. However, its dispersion in aqueous medium is challenging. This study aimed to modify graphene nanoparticles with L-dopa to improve the properties of experimental dental adhesives. Adhesives were formulated with 0% (control), 0.25%, 0.5%, and 0.75% of graphene, modified or not. Particle modification and dispersion were microscopically assessed. Degree of conversion was tested by Fourier-transform infrared spectroscopy. Flexural strength and modulus of elasticity were evaluated by a 3-point flexural test. Bond strength was tested by shear. To test water sorption/solubility, samples were weighed during hydration and dehydration. Antibacterial activity was tested by Streptococcus mutans colony-forming units quantification. Cytotoxicity on fibroblasts was evaluated through a dentin barrier test. The modification of graphene improved the particle dispersion. Control presented the highest degree of conversion, flexural strength, and bond strength. In degree of conversion, 0.25% of groups were similar to control. In bond strength, groups of graphene modified by L-dopa were similar to Control. The modulus of elasticity was similar between groups. Cytotoxicity and water sorption/solubility decreased as particles increased. Compared to graphene, less graphene modified by L-dopa was needed to promote antibacterial activity. By modifying graphene with L-dopa, the properties of graphene and, therefore, the adhesives incorporated by it were enhanced.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects motor and cognition functions. The etiology of Parkinson's disease remains largely unknown, but genetic and environmental factors are believed to play a role. The neurotransmitter dopamine is implicated in regulating movement, motivation, memory, and other physiological processes. In individuals with Parkinson's disease, the loss of dopaminergic neurons leads to a reduction in dopamine levels, which causes motor impairment and may also contribute to the cognitive deficits observed in some patients. Therefore, it is important to understand the pathophysiology that leads to the loss of dopaminergic neurons, along with reliable biomarkers that may help distinguish PD from other conditions, monitor its progression, or indicate a positive response to a therapeutic intervention. Important advances in the treatment, etiology, and pathogenesis of Parkinson's disease have been made in the past 50 years. Therefore, this review tries to explain the different possible mechanisms behind the depletion of dopamine in PD patients such as alpha-synuclein abnormalities, mitochondrial dysfunction, and 3,4-dihydroxyphenylacetaldehyde (DOPAL) toxicity, along with the current therapies we have and the ones that are in development. The clinical aspect of Parkinson's disease such as the manifestation of both motor and non-motor symptoms, and the differential diagnosis with similar neurodegenerative disease are also discussed.

Abstract Background Iron deficiency is the leading cause of anemia worldwide, particularly in countries with predominant plant-based diets. Plants constitute the main source of dietary iron. Increasing their iron concentration could reduce the occurrence of anemia. The water spinach Ipomoea aquatica is consumed as a vegetable throughout Asia and tolerates high iron concentrations making it an attractive candidate for iron biofortification. L-DOPA is an allelopathic molecule secreted by some legumes. L-DOPA can trigger the expression of Fe deficiency-inducible genes, and could potentially be used as a biostimulant to increase Fe concentration. Results L-DOPA significantly affected root growth of water spinach, and triggered a massive accumulation of Fe in roots. Both effects were exacerbated when L-DOPA was dissolved in KOH, which is surprising given that L-DOPA is less stable at high pH. To check whether a higher pH could indeed increase the bioactivity of L-DOPA, we used Arabidopsis thaliana, which grows at lower pH than water spinach, and subjected the plants to L-DOPA treatments at pH 5.5 and pH 6.0, which are both within the optimal range for Arabidopsis nutrition. At pH 6.0, the root growth of Arabidopsis was more strongly inhibited than at pH 5.5. We found that at higher pH, L-DOPA oxidizes to form a melanin precipitate. Conclusions We concluded that the oxidation of L-DOPA that we observed upon solubilization in KOH, or in nutrient solutions at slightly higher pH produces melanin-related molecules that are more potent than L-DOPA itself to trigger the primary root growth inhibition, Fe uptake and root Fe accumulation in water spinach and Arabidopsis.

The adenosine A2A receptor antagonist/inverse agonist, KW-6356 has been shown to be effective in Parkinson's disease (PD) patients as monotherapy and as an adjunct therapy to L-3,4-dihydroxyphenylalanine (L-DOPA)/decarboxylase inhibitor. However, the effects of KW-6356 combined with L-DOPA on anti-parkinsonian activity and established dyskinesia has not been investigated in preclinical experiments. We examined the effects of combination of KW-6356 with L-DOPA in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmosets. Oral administration of KW-6356 (1 mg/kg) enhanced the anti-parkinsonian activities of various doses of L-DOPA (2.5–10 mg/kg). In MPTP-treated common marmosets primed with L-DOPA to show dyskinesia, KW-6356 (1 mg/kg) also enhanced the anti-parkinsonian activities of various doses of L-DOPA (1.25–10 mg/kg) but not dyskinesia. Chronic co-administration of KW-6356 (1 mg/kg) with a low dose of L-DOPA (2.5 mg/kg) for 21 days increased the degree of dyskinesia induced by the low dose of L-DOPA, but the amplitude of dyskinesia induced by combined administration of KW-6356 (1 mg/kg) with L-DOPA (2.5 mg/kg) was lower than that induced by an optimal dose of L-DOPA (10 mg/kg). These results suggest that KW-6356 can be used to potentiate the effects of a wide range of L-DOPA doses with a low risk of dyskinesia for the treatment of PD.

Methylphenidate (MPH) and methamphetamine (METH) are the current treatments of choice for attention deficit/hyperactivity disorder. We previously reported that METH induces the release of dopamine (DA) and of the neurotransmitter candidate L-3,4-dihydroxyphenylalanine (L-DOPA). In contrast, we here found that MPH increased the DA release while it did not affect the L-DOPA release from the dorsolateral striatum. Nevertheless, MPH-induced hyperlocomotion was reduced in Gpr143 (L-DOPA receptor) gene-deficient (Gpr143−/y) mice. The rewarding effect and increased c-fos expression induced by MPH were also attenuated in Gpr143−/y mice. Together, these findings suggest that GPR143 is involved in the acute and chronic actions of MPH.

Abstract Tyrosine hydroxylase deficiency (THD) is a rare genetic disorder leading to dopaminergic depletion and early‐onset Parkinsonism. Affected children present with either a severe form that does not respond to L‐Dopa treatment (THD‐B) or a milder L‐Dopa responsive form (THD‐A). We generated induced pluripotent stem cells (iPSCs) from THD patients that were differentiated into dopaminergic neurons (DAn) and compared with control‐DAn from healthy individuals and gene‐corrected isogenic controls. Consistent with patients, THD iPSC‐DAn displayed lower levels of DA metabolites and reduced TH expression, when compared to controls. Moreover, THD iPSC‐DAn showed abnormal morphology, including reduced total neurite length and neurite arborization defects, which were not evident in DAn differentiated from control‐iPSC. Treatment of THD‐iPSC‐DAn with L‐Dopa rescued the neuronal defects and disease phenotype only in THDA‐DAn. Interestingly, L‐Dopa treatment at the stage of neuronal precursors could prevent the alterations in THDB‐iPSC‐DAn, thus suggesting the existence of a critical developmental window in THD. Our iPSC‐based model recapitulates THD disease phenotypes and response to treatment, representing a promising tool for investigating pathogenic mechanisms, drug screening, and personalized management.

Objective(s): Parkinson’s disease (PD) is one of the most incurable, chronic, and progressive neurodegenerative disorders Worldwide. Curcumin, a natural polyphenolic antioxidant compound, has a long history in traditional medicine. We investigate the effect of curcumin on brain oxidative stress, DNA fragmentation, and motor changes in rotenone-induced PD in mice. The possible modulation of the anti-parkinsonian action of drugs L-dopa and rasagiline by curcumin was also studied.Materials and Methods: Mice received rotenone 1.5 mg/kg and were treated with curcumin (150 mg/kg), L-dopa (25 mg/kg), rasagiline (1 mg/kg), L-dopa+curcumin, or rasagiline+curcumin. Striatal malondialdehyde, reduced glutathione, nitric oxide, tyrosine hydroxylase, and brain DNA fragmentations were measured. Histopathological examination of brain tissues was done. Motor coordination and behavioral tests such as wire-hanging, stair, and wood-waking tests were included.Results: Rotenone caused elevation in brain malondialdehyde and nitric oxide contents, depletion of reduced glutathione accompanied by a reduction in rearing behavior, and impairment of motor activity in wire-hanging, stair, and wood-waking tests. Also, severe DNA fragmentation in the striatum, marked decrease of substantia nigra pigmented neurons, neuronal degeneration in the cerebral cortex and hippocampus, decreased glial fibrillary acidic protein reaction (GFAP) and glial cell size in the cerebral cortex were caused by rotenone. In rotenone-treated mice, brain oxidative stress was decreased by curcumin, L-dopa, rasagiline, curcumin+L-dopa, and curcumin+rasagiline. These treatments also prevented DNA fragmentation and markedly improved the motor and behavioral impairment caused by rotenone. Rotenone-induced histopathological changes were ameliorated by curcumin which had an additive effect to that of l-dopa or rasagiline.Conclusion: These data indicate that curcumin showed additive neuroprotective effects to L-dopa or rasagiline and ameliorated neurodegeneration, DNA fragmentation, and motor defects caused by rotenone in mice.

Abstract Background Melanin is a natural pigment that can be applied in different fields such as medicine, environment, pharmaceutical, and nanotechnology. Studies carried out previously showed that the melanin produced by the mel1 mutant from Aspergillus nidulans exhibits antioxidant, anti-inflammatory, and antimicrobial activities, without any cytotoxic or mutagenic effect. These results taken together suggest the potential application of melanin from A. nidulans in the pharmaceutical industry. In this context, this study aimed to evaluate the effect of factors L-tyrosine, glucose, glutamic acid, l-DOPA, and copper on melanin production by the mel1 mutant and to establish the optimal concentration of these factors to maximize melanin production. Results The results showed that l-DOPA, glucose, and copper sulfate significantly affected melanin production, where l-DOPA was the only factor that exerted a positive effect on melanin yield. Besides, the tyrosinase activity was higher in the presence of l-DOPA, considered a substrate required for enzyme activation, this would explain the increased production of melanin in this condition. After establishing the optimal concentrations of the analyzed factors, the melanin synthesis was increased by 640% compared to the previous studies. Conclusions This study contributed to elucidating the mechanisms involved in melanin synthesis in A. nidulans as well as to determining the optimal composition of the culture medium for greater melanin production that will make it possible to scale the process for a future biotechnological application.

Zonisamide (ZNS; 1,2-benzisoxazole-3-methanesulfonamide) was initially developed and is commonly used as an anticonvulsant drug. However, it has also shown its beneficial effects on Parkinson's disease (PD), a progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the midbrain. Recent clinical studies have suggested that ZNS can also have beneficial effects on L-DOPA-induced dyskinesia (LID), which is a major side effect of long-term L-DOPA treatments for PD. In the present study, we examined the behavioral effects of ZNS on LID in PD model mice. Acute ZNS treatment did not have any observable behavioral effects on LID. Contrastingly, chronic ZNS treatment with L-DOPA delayed the peak of LID and reduced the severity of LID before the peak but increased the duration of LID in a dose-dependent manner of ZNS compared to PD model mice treated with L-DOPA alone. Thus, ZNS appears to have both beneficial and adverse effects on LID.

Polyphenol oxidase which is responsible for oxidative conversion of phenolic compounds to polymers, has continued to attract the attention of scientists. Here, we report the extraction, purification and biochemical properties of polyphenol oxidase (PPO) from bitter leaf (Vernonia amygdalina). The enzyme was purified and concentrated using a non-conventional approach, aqueous two-phase partitioning (ATPS) and the biochemical properties of the purified enzyme were investigated. Substrate specificity studies revealed that the enzyme predominantly exhibits diphenolase activity. The order of substrate preference was catechol > L-DOPA > caffeic acid > L-tyrosine > resorcinol>2-naphthol > phenol. The optimum pH and temperature obtained for the enzyme using catechol as substrate were 5.5 and 50 °C respectively. The estimated Michaelis constant (Km) and maximum velocity (Vmax) for the purified vaPPO using catechol as substrate were 183 ± 5.0 mM and 2000 ± 15 units/mg protein respectively. The catalytic efficiency (Vmax/Km) of the purified vaPPO was 10.9 ± 0.03 min/mg. Na+, K+ and Ba2+ remarkably activated the enzyme and the level of activation was proportional to the concentration. The vaPPO presented stability in the presence of up to 50 mM of the different metal ions tested. In contrast, Cu2+ and NH4+ inhibited the enzyme even 10 mM concentrations. The enzyme was stable in chloroform retaining up to 60% relative activity at 50% (v/v) concentration. There was an increase in the activity (143%) of the enzyme at 30% (v/v) chloroform., revealing that vaPPO could catalyze the substrate more efficiently in 30% (v/v) chloroform. Total loss of enzyme activity was observed at 20% (v/v) concentrations of acetone, ethanol and methanol.In conclusion, the properties of the vaPPO such as its catalysis in the presence of organic solvents, metals and high temperature would be of interest in many biotechnological applications.

This study aimed to investigate the effects of levodopa (L-dopa), p-coumaric acid, and combinations in the neuroblastoma (N1E-115) cell. L-dopa and L-dopa plus p-coumaric acid group caused oxidative stress by increasing 12.5 and 3.7-fold in superoxide dismutase gene, 11.5 and 4.8-fold increase in catalase gene, respectively. In L-dopa and L-dopa plus p-coumaric acid application, p21 gene expression increased 1.3-fold and 3.2-fold, and the cell cycle stopped in the G1 phase in response to stress in the treatment groups. In the application of L-dopa plus p-coumaric acid to N1E-115 cells, the BCL-2 gene, which is an apoptosis inhibitor, was suppressed and the BAX gene increased 13-fold compared to the control. As a result, it was determined that the cytotoxic effect of L-dopa plus p-coumaric acid application was less than the individual application of the substances, and p-coumaric acid had an inhibitory effect on L-dopa-induced stress.

Background and aims: Chronic stress is a major common cause of male infertility. Many species of velvet beans are shown to be rich in l-DOPA. In Thai folklore medicine, seeds of Mucuna pruriens (L.) DC. var. pruriens (Thai Mhamui or T-MP) have been used for treating erectile dysfunction. This study aimed to determine l-DOPA levels in T-MP seed extract and investigate its preventive on sexual behaviors and reproductive parameter damages including essential proteins in chronic unpredictable mild stress (CUMS) mice. Experimental procedure: Mice were divided into 4 groups: (I) control, (II) CUMS, (III) T-MP300 + CUMS, and (IV) T-MP600 + CUMS. Groups I and II received DW while groups III and IV were pretreated with the seed extracts (300 and 600 mg/kg BW) for 14 consecutive days before co-treatment with a randomly different CUMS/day (from 12 mild stressors) for 43 days. Results and conclusion: T-MP seed extract contained l-DOPA approximately 10% of total dried weight. A dose of 600 mg/kg improved sexual performances and degenerative seminiferous epithelium in CUMS mice. Sperm qualities and testosterone level were elevated while corticosterone was decreased in co-treatment groups. T-MP-CUMS cotreated groups also improved expressions of AKAP4, AR, and TyrPho proteins in testis, epididymis, and sperm. T-MP increased StAR and CYP11A1 expressions in testis. It also suppressed testicular apoptosis via decreased expressions of Hsp70, caspases 3, and 9. T-MP seeds containing l-DOPA could improve sexual behaviors and essential reproductive proteins caused by CUMS. Section: Natural Products; Taxonomy (classification by evise): Traditional Herbal Medicine; Animal Model; Histopathology.

Nitric oxide (NO) plays a pivotal role in integrating dopamine transmission in the basal ganglia and has been implicated in the pathogenesis of Parkinson disease (PD). The objective of this study was to ascertain whether the NO synthase inhibitor, 7-nitroindazole (7-NI), is able to reduce L-DOPA-induced dyskinesias (LIDs) in a non-human primate model of PD chronically intoxicated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Six Parkinsonian macaques were treated daily with L-DOPA for 3–4 months until they developed LIDs. Three animals were then co-treated with a single dose of 7-NI administered 45 min before each L-DOPA treatment. Dyskinetic MPTP-treated monkeys showed a significant decrease in LIDs compared with their scores without 7-NI treatment (p < 0.05). The anti-Parkinsonian effect of L-DOPA was similar in all three monkeys with and without 7-NI co-treatment. This improvement was significant with respect to the intensity and duration of LIDs while the beneficial effect of L-DOPA treatment was maintained and could represent a promising therapy to improve the quality of life of PD patients.

Noodles and chapatti having white or slightly yellow colour are preferred by consumers. Polyphenol oxidase (PPO) enzyme is responsible for discoloration of wheat products. One hundred wheat genotypes were screened using L-DOPA and phenol assays for PPO activity. Activity at 30 min and 90 min of incubation ranged from 13.78 to 100.27 and 5.38 to 72.18 au/min/g, respectively. Genotypes RAJ3766 (99.38), RAJ4266 (76.44) and DWR9507 (72.37) exhibited highest PPO activity, whereas NIAW2349 (18.05), BANSI988-18 (19.72) and NIAW2348 (19.94) showed lowest PPO activity. Interaction data indicated significant differences between genotypes and different seasons, emphasizing role of seasons on expression of PPO. Strong correlation was observed between PPO at 30 min and 90 min incubation. However, PPO30 could serve as a reliable estimate than PPO90. The correlation between PPO30 and phenol were not consistent and varied from strong (r=0.7304) to weak (r=0.2377) in different years.

L-DOPA is the mainstay of treatment for Parkinson’s disease (PD). However, over time this drug can produce dyskinesia. A useful acute PD model for screening novel compounds for anti-parkinsonian and L-DOPA-induced dyskinesia (LID) are dopamine-depleted dopamine-transporter KO (DDD) mice. Treatment with α-methyl-para-tyrosine rapidly depletes their brain stores of DA and renders them akinetic. During sensitization in the open field (OF), their locomotion declines as vertical activities increase and upon encountering a wall they stand on one leg or tail and engage in climbing behavior termed “three-paw dyskinesia”. We have hypothesized that L-DOPA induces a stereotypic activation of locomotion in DDD mice, where they are unable to alter the course of their locomotion, and upon encountering walls engage in “three-paw dyskinesia” as reflected in vertical counts or beam-breaks. The purpose of our studies was to identify a valid index of LID in DDD mice that met three criteria: (a) sensitization with repeated L-DOPA administration, (b) insensitivity to a change in the test context, and (c) stimulatory or inhibitory responses to dopamine D1 receptor agonists (5 mg/kg SKF81297; 5 and 10 mg/kg MLM55-38, a novel compound) and amantadine (45 mg/kg), respectively. Responses were compared between the OF and a circular maze (CM) that did not hinder locomotion. We found vertical counts and climbing were specific for testing in the OF, while oral stereotypies were sensitized to L-DOPA in both the OF and CM and responded to D1R agonists and amantadine. Hence, in DDD mice oral stereotypies should be used as an index of LID in screening compounds for PD.

L-Dopa is an intermediate amino acid in the biosynthesis of endogenous catecholamines, such as dopamine. It is currently considered to be the optimal dopaminergic treatment for Parkinson’s disease, a neurodegenerative disorder affecting around 1% of the population. In an advanced stage of the disease, complications such as dyskinesia and psychosis are caused by fluctuations in plasma drug levels. Real-time monitoring of L-Dopa levels would be advantageous for properly adjusting drug dosing, thus improving therapeutic efficacy. Electrochemical methods have advantages such as easy-to-use instrumentation, fast response time, and high sensitivity, and are suitable for miniaturization, enabling the fabrication of implantable or wearable devices. This review reports on research papers of the past 20 years (2003–2023) dealing with enzyme-based biosensors for the electrochemical detection of L-Dopa in biological samples. Specifically, amperometric and voltammetric biosensors, whose output signal is a measurable current, are discussed. The approach adopted includes an initial study of the steps required to assemble the devices, i.e., electrode modification and enzyme immobilization. Then, all issues related to their analytical performance in terms of sensitivity, selectivity, and capability to analyze real samples are critically discussed. The paper aims to provide an assessment of recent developments while highlighting limitations such as poor selectivity and long-term stability, and the laborious and time-consuming fabrication protocol that needs to be addressed from the perspective of the integrated clinical management of Parkinson’s disease.

L-DOPA, the precursor of catecholamines, exerts a pro-locomotor action in several vertebrate species, including newborn rats. Here, we tested the hypothesis that decreasing the degradation of monoamines can promote the pro-locomotor action of a low, subthreshold dose of L-DOPA in five-day-old rats. The activity of the degrading pathways involving monoamine oxidases or catechol-O-methyltransferase was impaired by injecting nialamide or tolcapone, respectively. At this early post-natal stage, the capacity of the drugs to trigger locomotion was investigated by monitoring the air-stepping activity expressed by the animals suspended in a harness above the ground. We show that nialamide (100 mg/kg) or tolcapone (100 mg/kg), without effect on their own promotes maximal expression of air-stepping sequences in the presence of a sub-effective dose of L-DOPA (25 mg/kg). Tissue measurements of monoamines (dopamine, noradrenaline, serotonin and some of their metabolites) in the cervical and lumbar spinal cord confirmed the regional efficacy of each inhibitor toward their respective enzyme. Our experiments support the idea that the raise of monoamines boost L-DOPA’s locomotor action. Considering that both inhibitors differently altered the spinal monoamines levels in response to L-DOPA, our data also suggest that maximal locomotor response can be reached with different monoamines environment.

Pulmonary hypertension (PH) is a severe and progressive disease that causes elevated right ventricular systolic pressure, right ventricular hypertrophy and ultimately right heart failure. However, the underlying pathophysiologic mechanisms are poorly understood. We previously showed that 3,4-l-dihydroxylphenyalanine (DOPA) sensitizes vasomotor response to sympathetic tone via coupling between the adrenergic receptor alpha1 (ADRA1) and a G protein-coupled receptor 143 (GPR143), a DOPA receptor. We investigated whether DOPA similarly enhances ADRA1-mediated contraction in pulmonary arteries isolated from rats, and whether GPR143 is involved in the PH pathogenesis. Pretreating the isolated pulmonary arteries with DOPA 1 μM enhanced vasoconstriction in response to phenylephrine, an ADRA1 agonist, but not to U-46619, a thromboxane A2 agonist or endothelin-1. We generated Gpr143 gene-deficient (Gpr143-/y) rats, and confirmed that DOPA did not augment phenylephrine-induced contractile response in Gpr143-/y rat pulmonary arteries. We utilized a rat model of monocrotaline (MCT)-induced PH. In the MCT model, the right ventricular systolic pressure was attenuated in the Gpr143-/y rats than in WT rats. Phenylephrine-induced cell migration and proliferation were also suppressed in Gpr143-/y pulmonary artery smooth muscle cells than in WT cells. Our result suggests that GPR143 is involved in the PH pathogenesis in the rat models of PH.

Mucuna pruriens (L.) DC (Velvet beans) is a tropical bean containing large amounts of l-Dopa (L-3,4-dihydroxyphenylalanine) and is the most important natural remedy for Parkinson’s disease. This plant has been used in Ayurveda medicine because it has a pharmacological activity, one of which is an antibacterial activity obtained from its seed extract. M. pruriens seeds fulfill the basic nutritional requirements, so they can be consumed. However, their utilization as food is limited due to the presence of some anti-nutritional factors. The objective of the research was to determine the nutritional content of seeds of M. pruriens Central Java accession by proximate analysis, isolation, and characterization of l-Dopa, determine the toxicity value ( LC50), against Artemia salina L. larvae by BSLT (brine shrimp lethality test), and determine its antibacterial activity against Streptococcus mutans ATCC 35668, and Escherichia coli ATCC 25,922 by agar disk diffusion method. The isolate of l-Dopa was prepared by maceration using methanol 80%, followed by extraction using water, then, the isolated product was analyzed by analytical TLC to determine the suitable mobile phase. The sample was then run on preparative TLC. The spot that corresponds to the l-Dopa standard was collected and further purified using adsorption column chromatography. Then, the isolate was characterized by HPLC and FTIR. The antioxidant activity was determined by the DPPH radical method. Finally, anti-Parkinson's activity was determined to the rotenone-induced behavior of white rats (Rattus norvegicus) by the classic labyrinth test method. The result showed that the strongest antibacterial activity against S. mutans ATCC 35,668 was shown by crude extract. Based on the HPLC analysis, the isolated l-Dopa showed a retention time of 5.345 min that is relatively similar to the l-Dopa standard and had a high purity. l-Dopa content in M. pruriens seed of Central Java accession was 0.49 mg/g dry weight. The l-Dopa isolate from M. pruriens Central Java accession has antioxidant activity with IC50 of 8.92 ± 0.03 ppm (highly active) and could significantly reduce the non-motoric Parkinsonism symptoms (p

Dopamine is considered an important molecule that plays several essential roles in the human body, and herein lies the key to this paper on the electronic and optical properties of dopamine and its derivatives, such as quinone and L-dihydroxyphenylalanine (L-DOPA), using DFT and TD-DFT methods, respectively. Our findings show that dopamine has a dielectric behavior, whereas quinone and L-DOPA have semiconductor behaviors in the ground and excited states. By computing the optical properties, we disclose that the electronic transition spectrum of dopamine, quinone and L-DOPA are observed in the ultra-violet region, visible spectrum, and (ultraviolet and visible regions), respectively. Other properties, such as ionization potential, electronic affinity, hardness and softness are also calculated due to their importance in sensor applications and sensing.

3,4-dihydroxy-L-phenylalanine (L-DOPA) is one of the precursor molecules for the biosynthesis of neurotransmitters in the brain. Monitoring of L-DOPA levels as a drug or biomolecule in biological fluids is crucial for the treatment of patients suffering from Parkinson’s Disease. This study aimed to construct a cloud funnel mushroom (Clitocybe nebularis (Batsch), P. Kumm.) tissue homogenate-based biosensor for precise and sensitive detection of L-DOPA in artificial plasma and urine. For this purpose, in the fabrication of the biosensor, tissue homogenate of C. nebularis was immobilized into a carbon paste electrode by using graphite, mineral oil, gelatine and glutaraldehyde. The amperometric signals corresponding to 600 s were recorded as response current for each L-DOPA concentration. All amperometric measurements were carried out at ⁻700 mV (versus Ag|AgCl). The present biosensor successfully detected L-DOPA with a linear dynamic range at 2.5-100 µM and Limit of Detection (LOD) value as 0.76 µM, as well as standard deviation as ±0.41 µM and coefficient of variation as 0.82% (n=16). Additionally, the determination of L-DOPA spiked in artificial plasma and urine was carried out successfully. The present work would be the first study that utilized C. nebularis tissue as a biosensor component.

Objective(s): Polyethylenimine (PEI) is one of the most-extensively investigated cationic polymers for gene and drug delivery. Recently, great attention has been directed to design of carriers for co-delivery of nucleic acids and small molecules. These delivery systems are able to overcome the limitations of gene or drug delivery alone. The aim of this study is to prepare a targeted nano-carrier for co-delivery of doxorubicin (Dox) and gene using polyethylenimine. Materials and Methods: In order to prepare the ligand-containing polymer conjugates, succinic anhydride was conjugated onto the hydroxyl group of Dox through an ester bond following the protection of Dox amines by Fmoc. Drug-polymer conjugates were then coupled with L-DOPA in order to prepare the targeted nanocarriers to the cells through Large Amino Acid Transporter-1 (LAT-1). The PEI derivatives were characterized using 1H-NMR. The toxicity of conjugated polymer, Dox and PEI was assessed on HepG2 and A375 cell lines with different expression level of LAT-1 transporters using MTT assay. Results: The chemical structure of PEI conjugate was confirmed by 1H-NMR. The cytotoxicity measurement demonstrated a cell line-dependent toxicity profile at the concentrations tested in this study. It was shown that there was no significant difference in cell-induced toxicity between conjugated polymer and its parent form in A375 cell line while the cytotoxicity of conjugated polymer was significantly lower than the parent PEI in HepG2 cells.Conclusion: These results provide promising evidence for further evaluation of PEI conjugate for co-delivery of drug and gene via LAT-1 transporters.

Abstract Tetrahydrobiopterin (BH4) is a cofactor that participates in the biogenesis reactions of a variety of biomolecules, including l‐tyrosine, l‐3,4‐dihydroxyphenylalanine, 5‐hydroxytryptophan, nitric oxide, and glycerol. Dihydropteridine reductase (DHPR, EC 1.5.1.34) is an enzyme involved in the BH4 regeneration. DHPR deficiency (DHPRD) is an autosomal recessive disorder, leading to severe and progressive neurological manifestations, which cannot be exclusively controlled by l‐phenylalanine (l‐Phe) restricted diet. In fact, the supplementation of neurotransmitter precursors is more decisive in the disease management, and the administration of sapropterin dihydrochloride may also provide positive effects. From the best of our knowledge, there is limited information regarding DHPRD in the past 5 years in the literature. Here, we describe the medical journey of the first patient to have DHPRD confirmed by molecular diagnostic methods in Brazil. The patient presented with two pathogenic variants of the quinoid dihydropteridine reductase (QDPR) gene—which codes for the DHPR protein, one containing the in trans missense mutation c.515C>T (pPro172Leu) in exon 5 and the other containing the same type of mutation in the exon 7 (c.635T>C [p.Phe212Ser]). The authors discuss their experience with sapropterin dihydrochloride for the treatment of DHPRD in this case report.

Objective(s): Human Wharton’s jelly-derived mesenchymal stem cells (hWJ-MSCs) have been recognized as a potential tool to replace damaged cells by improving the survival of the dopaminergic cells in Parkinson’s disease (PD). In this study, we examined the effects of hWJ-MSCs and associated with L-dopa/carbidopa on motor disturbances in the PD model. Materials and Methods: PD was induced by injection of 6-hydroxydopamine (6-OHDA) (16 μg/2 μl into medial forebrain bundle (MFB)). Sham group received a vehicle instead of 6-OHDA. PD+C group received hWJ-MSCs twice on the 14th and 28th days post PD induction. PD+C+D group received hWJ-MSCs and also L-dopa/carbidopa (10/30 mg/kg). PD+D group received L-dopa/carbidopa alone. Four months later, motor activities (the parameters of locomotor and muscle stiffness) were evaluated, dopaminergic neurons were counted in substantia nigra pars compacta (SNc), the level of dopamine (DA), and tyrosine hydroxylase (TH) were measured in the striatum. Results: Data indicated that motor activities, the number of dopaminergic neurons, and levels of DA and TH activities were significantly reduced in PD rats as compared to the sham group (p

The theory of electron spin has been proposed for a century, but the study of quantum effects in biological molecules is still in its infancy. Chirality-induced spin selectivity (CISS) is a very modern theory that can explain many biochemical phenomena. In this paper, we propose a new theoretical model based on CISS theory and quantum chemistry theory, which can well explain the theoretical explanation of the chiral selectivity of chiral proteins. Moreover, this theory can predict the spin state of corresponding chiral molecules. Taking the L-DOPA and AADC enzymes as examples, this theoretical model elucidates the AADC enzyme’s chiral catalysis selectivity and successfully predicts the spin state of L-DOPA and D-DOPA’s valence electrons.

The use of transcriptomic data to make inferences about plant metabolomes is a useful tool to help the discovery of important compounds in the available biodiversity. To unveil previously undiscovered metabolites of Coffea, of phytotherapeutic and economic value, we employed 24 RNAseq libraries. These libraries were sequenced from leaves exposed to a diverse range of environmental conditions. Subsequently, the data were meticulously processed to create models of putative metabolic networks, which shed light on the production of potential natural compounds of significant interest. Then, we selected one of the predicted compounds, the L-3,4-dihydroxyphenylalanine (L-DOPA), to be analyzed by LC–MS/MS using three biological replicates of flowers, leaves, and fruits from Coffea arabica and Coffea canephora. We were able to identify metabolic pathways responsible for producing several compounds of economic importance. One of the identified pathways involved in isoquinoline alkaloid biosynthesis was found to be active and producing L-DOPA, which is a common product of POLYPHENOL OXIDASES (PPOs, EC 1.14.18.1 and EC 1.10.3.1). We show that coffee plants are a natural source of L-DOPA, a widely used medicine for treatment of the human neurodegenerative condition called Parkinson’s disease. In addition, dozens of other compounds with medicinal significance were predicted as potential natural coffee products. By further refining analytical chemistry techniques, it will be possible to enhance the characterization of coffee metabolites, enabling a deeper understanding of their properties and potential applications in medicine.

Statins have been proposed for L-DOPA-induced dyskinesia (LID) treatment. Statin anti-dyskinetic effects were related to the inhibition of the Ras-ERK pathway. However, the mechanisms responsible for the anti-LID effect are unclear. Changes in cholesterol homeostasis and oxidative stress- and inflammation-related mechanisms such as angiotensin II and Rho-kinase (ROCK) inhibition may be involved. The nigra and striatum of dyskinetic rats showed increased levels of cholesterol, ROCK, and the inflammatory marker IL-1β, which were reduced by the angiotensin type-1 receptor (AT1) antagonist candesartan, simvastatin, and the ROCK inhibitor fasudil. As observed for LID, angiotensin II-induced, via AT1, increased levels of cholesterol and ROCK in the rat nigra and striatum. In cultured dopaminergic neurons, angiotensin II increased cholesterol biosynthesis and cholesterol efflux without changes in cholesterol uptake. In astrocytes, angiotensin induced an increase in cholesterol uptake, decrease in biosynthesis, and no change in cholesterol efflux, suggesting a neuronal accumulation of cholesterol that is reduced via transfer to astrocytes. Our data suggest mutual interactions between angiotensin/AT1, cholesterol, and ROCK pathways in LID, which are attenuated by the corresponding inhibitors. Interestingly, these three drugs have also been suggested as neuroprotective treatments against Parkinson’s disease. Therefore, they may reduce dyskinesia and the progression of the disease using common mechanisms.

L-Dopa, a bioactive compound naturally occurring in some Leguminosae plants, is the most effective symptomatic drug treatment for Parkinson’s disease. During disease progression, fluctuations in L-DOPA plasma levels occur, causing motor complications. Sensing devices capable of rapidly monitoring drug levels would allow adjusting L-Dopa dosing, improving therapeutic outcomes. A novel amperometric biosensor for L-Dopa detection is described, based on tyrosinase co-crosslinked onto a graphene oxide layer produced through electrodeposition. Careful optimization of the enzyme immobilization procedure permitted to improve the long-term stability while substantially shortening and simplifying the biosensor fabrication. The effectiveness of the immobilization protocol combined with the enhanced performances of electrodeposited graphene oxide allowed to achieve high sensitivity, wide linear range, and a detection limit of 0.84 μM, suitable for L-Dopa detection within its therapeutic window. Interference from endogenous compounds, tested at concentrations levels typically found in drug-treated patients, was not significant. Ascorbic acid exhibited a tyrosinase inhibitory behavior and was therefore rejected from the enzymatic layer by casting an outer Nafion membrane. The proposed device was applied for L-Dopa detection in human plasma, showing good recoveries.

Impairment of balanced activity between dopamine D1 and D2 receptor functions in the striatum, particularly in striatal functional subdivisions (i.e., striosome and matrix compartments), has been proposed to underlie dystonia genesis. This study was undertaken to examine the therapeutic effect of dual dopaminergic modulation with L-3,4-dihydroxyphenylalanine (L-DOPA) and chlorpromazine (CPZ) in patients with blepharospasm, a focal dystonia. For this purpose, Dopacol tablets™ (L-DOPA 50 mg plus carbidopa 5 mg) and Wintermin™ (CPZ phenolphthalinate 180 mg/g) were used. Clinical evaluations were performed before and after an 8-week drug treatment interval using the Visual Analog Scale (VAS), Blepharospasm Disability Index (BSDI), modified VAS (mVAS), and Jankovic Rating Scale (JRS). The data were analyzed using non-parametric statistics. Results showed that in patients (n = 7) with blepharospasm, dystonia symptoms were significantly alleviated by the administration of both Dopacol tablets™ (one tablet × 3/day) and CPZ (5 mg × 3/day), as determined using the VAS, BSDI, mVAS, and JRS. In contrast, there was no improvement of dystonia symptoms in patients (n = 7) who ingested Dopacol tablets™ (one tablet × 3/day) alone, nor in those (n = 7) who ingested CPZ (5 mg × 3/day) alone. Thus, dual pharmacotherapy with L-DOPA and CPZ can exert a therapeutic effect on blepharospasm, suggesting that dystonia symptoms can be attenuated through dopaminergic modulation with inducing an increase in striatal D1-signals. Since dopamine D1 receptors are heavily enriched in the striosome compartment in the “human” striatum, our results also suggest that striosomal loss of D1-signaling may be important in the pathogenesis of dystonia.

Abstract Objectives The present study describes clinical, biochemical, molecular genetic data, current treatment strategies and follow‐up in nine patients with tetrahydrobiopterin (BH4) deficiency due to various inherited genetic defects. Methods We analyzed clinical, biochemical, and molecular data of nine patients with suspected BH4 deficiency. All patients were diagnosed at Ege University Faculty of Medicine in Izmir, Turkey and comprised data collected from 2006 to 2019. The diagnostic laboratory examinations included blood phenylalanine and urinary or plasma pterins, dihydropteridine reductase (DHPR) enzyme activity measurement in dried blood spots, folic acid and monoamine neurotransmitter metabolites in cerebrospinal fluid, as well as DNA sequencing. Results Among the nine patients, we identified one with autosomal recessive GTP cyclohydrolase I (ar GTPCH) deficiency, two with 6‐pyruvoyl‐tetrahydropterin synthase (PTPS) deficiency, three with sepiapterin reductase (SR) deficiency, and three with DHPR deficiency. Similar to previous observations, the most common clinical symptoms are developmental delay, intellectual disability, and movement disorders. All patients received treatment with l‐dopa and 5‐hydroxytryptophan, while only the ar GTPCH, the PTPS, and one DHPR deficient patients were supplemented in addition with BH4. The recommended dose range varies among patients and depends on the type of disease. The consequences of BH4 deficiencies are quite variable; however, early diagnosis and treatment will improve outcomes. Conclusions As BH4 deficiencies are rare group of treatable neurometabolic disorders, it is essential to diagnose the underlying (genetic) defect in newborns with hyperphenylalaninemia. Irreversible brain damage and progressive neurological deterioration may occur in untreated or late diagnosed patients. Prognosis could be satisfying in the cases with early diagnose and treatment.

Parkinson's disease (PD) is characterised by motor alterations, which are commonly treated with l-DOPA. However, long-term l-DOPA use may cause dyskinesia. Although the pathogenic mechanism of l-DOPA-induced dyskinesia is unclear, the condition has been associated with alterations in dopamine receptors, among which D2 receptors (D2R) have received little attention. This study aims to: (i) develop and standardise an experimental model of l-DOPA-induced dyskinesia in rats with hemiparkinsonism; and (ii) evaluate the correlation between D2R expression and presence of abnormal involuntary movements (AIM). We allocated 21 male Wistar rats into 3 groups: intact controls, lesioned rats (with neurotoxin 6-hydroxydopamine (6-OHDA)), and dyskinetic rats (injected with l-DOPA for 19 days). Sensorimotor impairment was assessed with behavioural tests. Dyskinetic rats gradually developed AIMs during the treatment period; front leg AIMs were more severe and locomotor AIMs less severe (P

Resumen: La enfermedad de Parkinson (EP) se caracteriza por una serie de deficiencias motoras que son tratadas comúnmente con L-DOPA; sin embargo, tras un uso crónico se desarrollan disquinesias inducidas por L-DOPA (DIL). Por otra parte, el origen de las DIL no está del todo claro, pero se asocia con alteración en receptores dopaminérgicos, donde los receptores D2 (RD2) han sido poco estudiados. El presente trabajo buscó: 1) desarrollar y estandarizar un modelo experimental de disquinesia con L-DOPA en ratas hemiparkinsonizadas, y 2) evaluar la correlación entre la expresión del RD2 y la manifestación de movimientos involuntarios anormales (MIA). Se utilizaron 21 ratas Wistar macho asignadas a 3 grupos: control intacto, lesionados (con la neurotoxina 6-OHDA) y lesionados disquinéticos (inyectados con L-DOPA durante 19 días). Los reactivos biológicos se sometieron a pruebas comportamentales para evaluar el deterioro sensoriomotor. Los animales del grupo disquinético desarrollaron de forma gradual MIA durante el tratamiento, siendo mayores los MIA de miembro anterior y menores los de tipo locomotor (p

This study aimed to determine the L-DOPA content in the flowers of some different faba bean genotypes and determine the L-DOPA levels in tea prepared from flowers. The experiment was carried out under the ecological conditions in Samsun by the Black Sea with 15 genotypes using a randomized complete block design in three replications. The flowers were harvested three times and the number of flowers and flower yields were determined. The L-DOPA content of the flower and flower tea were determined using HPLC. Different solvents were used to extract the L-DOPA from the faba bean flowers. As a result of the HPLC analyses, the highest L-DOPA yield was determined to be in the tea samples brewed with hot water. It was found statistical differences between genotypes in the second and third harvests for the number of flowers in the plant and the total number of flowers. Dry flower yields ranged from 11.33 to 37.78 kg da−1 while L-DOPA levels were 6.2 to 9.17 g 100g−1 in dry flowers and 6.69 to 9.23 g 100g−1 in infused tea. The study concluded that flower tea of faba bean can be investigate for medicinal purposes and that L-DOPA in the plant can be extracted by brewing without requiring any solvent. This shows that L-DOPA is in a salt form within the plant.

Andrea Fabbrini,1 Andrea Guerra2 1Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy; 2IRCCS Neuromed, Pozzilli, IS, ItalyCorrespondence: Andrea GuerraIRCCS Neuromed, Sapienza University of Rome, Via Atinense 18, Pozzilli, 86077, IS, ItalyEmail andrea.guerra@uniroma1.itAbstract: L-dopa-induced dyskinesia (LID) is the most frequent motor complication associated with chronic L-dopa treatment in Parkinson’s disease (PD). Recent advances in the understanding of the pathophysiological mechanisms underlying LID suggest that abnormalities in multiple neurotransmitter systems, in addition to dopaminergic nigrostriatal denervation and altered dopamine release and reuptake dynamics at the synaptic level, are involved in LID development. Increased knowledge of neurobiological LID substrates has led to the development of several drug candidates to alleviate this motor complication. However, with the exception of amantadine, none of the pharmacological therapies tested in humans have demonstrated clinically relevant beneficial effects. Therefore, LID management is still one of the most challenging problems in the treatment of PD patients. In this review, we first describe the known pathophysiological mechanisms of LID. We then provide an updated report of experimental pharmacotherapies tested in clinical trials of PD patients and drugs currently under study to alleviate LID. Finally, we discuss available pharmacological LID treatment approaches and offer our opinion of possible issues to be clarified and future therapeutic strategies.Keywords: dyskinesia, L-dopa, Parkinson’s disease, glutamate, serotonin, therapy