Machine learning driven web-based app platform for the discovery of monoamine oxidase B inhibitors.

Monoamine oxidases (MAOs), specifically MAO-A and MAO-B, play important roles in the breakdown of monoamine neurotransmitters. Therefore, MAO inhibitors are crucial for treating various neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS). In this study, we developed a novel cheminformatics pipeline by generating three diverse molecular feature-based machine learning-assisted quantitative structural activity relationship (ML-QSAR) models concerning MAO-B inhibition. PubChem fingerprints, substructure fingerprints, and one-dimensional (1D) and two-dimensional (2D) molecular descriptors were implemented to unravel the structural insights responsible for decoding the origin of MAO-B inhibition in 249 non-reductant molecules. Based on a random forest ML algorithm, the final PubChem fingerprint, substructure fingerprint, and 1D and 2D molecular descriptor prediction models demonstrated significant robustness, with correlation coefficients of 0.9863, 0.9796, and 0.9852, respectively. The significant features of each predictive model responsible for MAO-B inhibition were extracted using a comprehensive variance importance plot (VIP) and correlation matrix analysis. The final predictive models were further developed as a web application, MAO-B-pred ( https://mao-b-pred.streamlit.app/ ), to allow users to predict the bioactivity of molecules against MAO-B. Molecular docking and dynamics studies were conducted to gain insight into the atomic-level molecular interactions between the ligand-receptor complexes. These findings were compared with the structural features obtained from the ML-QSAR models, which supported the mechanistic understanding of the binding phenomena. The presented models have the potential to serve as tools for identifying crucial molecular characteristics for the rational design of MAO-B target inhibitors, which may be used to develop effective drugs for neurodegenerative disorders.

Correction: Isatin-based benzyloxybenzene derivatives as monoamine oxidase inhibitors with neuroprotective effect targeting neurodegenerative disease treatment.

[This corrects the article DOI: 10.1039/D3RA07035B.].

A comprehensive review of discovery and development of drugs discovered from 2020-2022.

To fully evaluate and define the new drug molecule for its pharmacological characteristics and toxicity profile, pre-clinical and clinical studies are conducted as part of the drug research and development process. The average time required for all drug development processes to finish various regulatory evaluations ranges from 11.4 to 13.5 years, and the expense of drug development is rising quickly. The development in the discovery of newer novel treatments is, however, largely due to the growing need for new medications. Methods to identify Hits and discovery of lead compounds along with pre-clinical studies have advanced, and one example is the introduction of computer-aided drug design (CADD), which has greatly shortened the time needed for the drug to go through the drug discovery phases. The pharmaceutical industry will hopefully be able to address the present and future issues and will continue to produce novel molecular entities (NMEs) to satisfy the expanding unmet medical requirements of the patients as the success rate of the drug development processes is increasing. Several heterocyclic moieties have been developed and tested against many targets and proved to be very effective. In-depth discussion of the drug design approaches of newly found drugs from 2020 to 2022, including their pharmacokinetic and pharmacodynamic profiles and in-vitro and in-vivo assessments, is the main goal of this review. Considering the many stages these drugs are going through in their clinical trials, this investigation is especially pertinent. It should be noted that synthetic strategies are not discussed in this review; instead, they will be in a future publication.

Isatin-based benzyloxybenzene derivatives as monoamine oxidase inhibitors with neuroprotective effect targeting neurogenerative disease treatment.

Eighteen isatin-based benzyloxybenzaldehyde derivatives from three subseries, ISB, ISFB, and ISBB, were synthesized and their ability to inhibit monoamine oxidase (MAO) was evaluated. The inhibitory activity of all synthesized compounds was found to be more profound against MAO-B than MAO-A. Compound ISB1 most potently inhibited MAO-B with an IC50 of 0.124 ± 0.007 µM, ensued by ISFB1 (IC50 = 0.135 ± 0.002 µM). Compound ISFB1 most potently inhibited MAO-A with an IC50 of 0.678 ± 0.006 µM, ensued by ISBB3 (IC50 = 0.731 ± 0.028 µM), and had the highest selectivity index (SI) value (55.03). The three sub-parental compounds, ISB1, ISFB1, and ISBB1, had higher MAO-B inhibition than the other derivatives, indicating that the substitutions of the 5-H in the A-ring of isatin diminished the inhibition of MAO-A and MAO-B. Among these, ISB1 (para-benzyloxy group in the B-ring) displayed more significant MAO-B inhibition when compared to ISBB1 (meta-benzyloxy group in the B-ring). ISB1 and ISFB1 were identified to be competitive and reversible MAO-B inhibitors, having Ki values of 0.055 ± 0.010, and 0.069 ± 0.025 µM, respectively. Furthermore, in the parallel artificial membrane penetration assay, ISB1 and ISFB1 traversed the blood-brain barrier in the in vitro condition. Additionally, the current study found that ISB1 decreased rotenone-induced cell death in SH-SY5Y neuroblastoma cells. In docking and simulation studies, the hydrogen bonding formed by the imino nitrogen in ISB1 and the pi-pi stacking interaction of the phenyl ring in isatin significantly aided in the protein-ligand complex's stability, effectively inhibiting MAO-B. According to these observations, the MAO-B inhibitors ISB1 and ISFB1 were potent, selective, and reversible, making them conceivable therapies for neurological diseases.

In silico development of potential InhA inhibitors through 3D-QSAR analysis, virtual screening and molecular dynamics.

Tuberculosis is one of the most ancient infectious diseases known to mankind predating upper Paleolithic era. In the current scenario, treatment of drug resistance tuberculosis is the major challenge as the treatment options are limited, less efficient and more toxic. In our study we have developed an atom based 3D QSAR model, statistically validated sound with R2 > 0.90 and Q2 > 0.72 using reported direct inhibitors of InhA (2018-2022), validated by enzyme inhibition assay. The model was used to screen a library of 3958 molecules taken from Binding DB and candidates molecules with promising predicted activity value (pIC50) > 5) were selected for further analyzed screening by using molecular docking, ADME profiling and molecular dynamic simulations. The lead molecule, ZINC11536150 exhibited good docking score (glideXP = -11.634 kcal/mol) compared to standard triclosan (glideXP = -7.129 kcal/mol kcal/mol) and through molecular dynamics study it was observed that the 2nv6-complex of ZINC11536150 with Mycobacterium tuberculosis InhA (PDB entry: 2NV6) complex remained stable throughout the entire simulation time of 100 ns.Communicated by Ramaswamy H. Sarma.

"Click Chemistry": An Emerging Tool for Developing a New Class of Structural Motifs against Various Neurodegenerative Disorders.

Click chemistry is a set of easy, atom-economical reactions that are often utilized to combine two desired chemical entities. Click chemistry accelerates lead identification and optimization, reduces the complexity of chemical synthesis, and delivers extremely high yields without undesirable byproducts. The most well-known click chemistry reaction is the 1,3-dipolar cycloaddition of azides and alkynes to form 1,2,3-triazoles. The resulting 1,2,3-triazoles can serve as both bioisosteres and linkers, leading to an increase in their use in the field of drug discovery. The current Review focuses on the use of click chemistry to identify new molecules for treating neurodegenerative diseases and in other areas such as peptide targeting and the quantification of biomolecules.

Development of a New Class of Monoamine Oxidase-B Inhibitors by Fine-Tuning the Halogens on the Acylhydrazones.

A total of 14 acyl hydrazine derivatives (ACH1-ACH14) were developed and examined for their ability to block monoamine oxidase (MAO). Thirteen analogues showed stronger inhibition potency against MAO-B than MAO-A. With a half-maximum inhibitory concentration of 0.14 µM, ACH10 demonstrated the strongest inhibitory activity against MAO-B, followed by ACH14, ACH13, ACH8, and ACH3 (IC50 = 0.15, 0.18, 0.20, and 0.22 µM, respectively). Structure-activity relationships suggested that the inhibition effect on MAO-B resulted from the combination of halogen substituents of the A- and/or B-rings. This series concluded that when -F was substituted to the B-ring, MAO-B inhibitory activities were high, except for ACH6. In the inhibition kinetics study, the compounds ACH10 and ACH14 were identified as competitive inhibitors, with Ki values of 0.097 ± 0.0021 and 0.10 ± 0.038 µM, respectively. In a reversibility experiment using the dialysis methods, ACH10 and ACH14 showed effective recoveries of MAO-B inhibition as much as lazabemide, a reversible reference. These experiments proposed that ACH10 and ACH14 were efficient, reversible competitive MAO-B inhibitors. In addition, the lead molecules showed good blood-brain barrier permeation with the PAMPA method. The molecular docking and molecular dynamics simulation study confirmed that the hit compound ACH10 can form a stable protein-ligand complex by forming a hydrogen bond with the NH atom in the hydrazide group of the compound.

Design and construction of novel pyridine-pyrimidine hybrids as selective COX-2 suppressors: anti-inflammatory potential, ulcerogenic profile, molecular modeling and ADME/Tox studies.

NSAIDs represent a mainstay in pain and inflammation suppression, and their actions are mainly based on inhibiting COX-1 and COX-2 enzymes.Due to the adverse effects of these drugs, especially on the stomach and heart, scientists efforts have been directed to manufacture selective COX-2 without cardiovascular side effects and with minimal effects on the stomach. The cardiovascular side effects are thought to be related to the chemical composition rather than mechanism of action of these drugs.Novel pyridopyrimidines, 9a-j, were prepared and their chemical structures were confirmed by NMR, mass and IR Spectra, and elemental analysis. The effect of the 9a-j compounds on COX-1 and COX-2 was assessed and it was found that 2-hydrazino-5-(4-methoxyphenyl)-7-phenyl-3H-pyrido[2,3-d)pyrimidin-4-one (9d) was the most potent COX-2 inhibitor (IC50 = 0.54 uM) compared to celecoxib (IC50 = 1.11 uM) with selectivity indices of 6.56 and 5.12, respectively.The in vivo inhibition of paw edema of novel compounds 9a-j was measured using carrageenan-induced paw edema method, and that 2-hydrazino-5-(4-methoxyphenyl)-7-phenyl-3H-pyrido[2,3-d)pyrimidin-4-one (9d) showed the best inhibitory activity in comparison with the other compounds and celecoxib.The gastroprotective effect of the potent derivatives 9d, 9e, 9f, 9 g and 9h was investigated. 2-Hydrazino-5-(4-methoxyphenyl)-7-phenyl-3H-pyrido[2,3-d)pyrimidin-4-one (9d) and 7-(chlorophenyl)-hydrazino-5-(4-methoxyphenyl)-3H-pyrido[2,3-d)pyrimidin-4-one (9e) showed ulcer indices comparable to celecoxib (1 and 0.5 vs 0.5, respectively). Docking studies were carried out and they confirmed the mechanistic action of the designed compoundsCommunicated by Ramaswamy H. Sarma.

Cytotoxic and Antioxidant Potential of Launaea mucronata Forssk Essential Oil Growing in Northern Saudi Arabia.

Essential oils are naturally occurring multicomponent combinations of isoprenoids with distinctive odors that are produced by aromatic plants from mevalonic acid. They are extensively applied in aromatherapy for the treatment of various ailments. To investigate the potential therapeutic value of the ingredients in Launaea mucronata essential oil (EO), gas chromatography-mass spectrometry (GC-MS) analysis was used for essential oil characterization. Then, 2,2-diphenyl-1-picrylhydrazyl (DPPH), ß-carotene/linoleic acid, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays were used to evaluate the antioxidants. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to estimate the cytotoxicity. Following a thorough analysis of the GC-MS chromatogram, 87 components representing 97.98% of the entire EO mixture were identified. N-eicosane (10.92%), 2E,6Z-farnesol (10.74%), and 2Z,6E-farnesyl acetone (46.35%) were determined to be the major components of the oil. When the produced EO was evaluated for its antioxidant properties, it showed a strong inhibitory effect (%) of 65.34 at a concentration of 80 µg/mL. The results (g/mL) showed a positive response against the tested cell lines for HCT-116, MCF-7, and HepG2 (8.45, 10.24, and 6.78 g/mL, respectively). A high-concentration mixture of deadly components consisting of farnesol, bisabolol, eicosane, and farnesyl acetone may be responsible for this significant cytotoxic action, which was especially noticeable in the HepG2 cell line. Molecular docking occurred between farnesol and farnesyl acetone with the target residues of topoisomerases I and II, CDK4/cyclD1, and Aurora B kinases; these showed binding free energies ranging from -4.5 to -7.4 kcal/mol, thus demonstrating their antiproliferative action. In addition, farnesol and farnesyl acetone fulfilled most of the ADME and drug-likeness properties, indicating their activity.

Piperidine: A Versatile Heterocyclic Ring for Developing Monoamine Oxidase Inhibitors.

The monoamine oxidase enzyme (MAO), which is bound on the membrane of mitochondria, catalyzes the oxidative deamination of endogenous and exogenous monoamines, including monoamine neurotransmitters such as serotonin, adrenaline, and dopamine. These enzymes have been proven to play a significant role in neurodegeneration; thus, they have recently been researched as prospective therapeutic targets for neurodegenerative illness treatment and management. MAO inhibitors have already been marketed as neurodegeneration illness treatments despite their substantial side effects. Hence, researchers are concentrating on developing novel molecules with selective and reversible inhibitory properties. Piperine, which is a phytochemical component present in black pepper, has been established as a potent MAO inhibitor. Piperine encompasses a piperidine nucleus with antibacterial, anti-inflammatory, antihypertensive, anticonvulsant, antimalarial, antiviral, and anticancer properties. The current Review focuses on the structural changes and structure-activity relationships of piperidine derivatives as MAO inhibitors.

A computational investigation of thymidylate synthase inhibitors through a combined approach of 3D-QSAR and pharmacophore modelling.

Thymidylate synthase (TS) is a crucial target of cancer drug discovery and is mainly involved in the De novo synthesis of the DNA precursor thymine. In the present study, to generate reliable models and identify a few promising molecules, we combined QSAR modelling with the pharmacophore hypothesis-generating technique. Input molecules were clustered on their similarity, and a cluster of 74 molecules with a pyrimidine moiety was chosen as the set for 3D-QSAR and pharmacophore modelling. Atom-based and field-based 3D-QSAR models were generated and statistically validated with R2 > 0.90 and Q2 > 0.75. The common pharmacophore hypothesis(CPH) generation identified the best six-point model ADHRRR. Using these best models, a library of FDA-approved drugs was screened for activity and filtered via molecular docking, ADME profiling, and molecular dynamics simulations. The top ten promising TS-inhibiting candidates were identified, and their chemical features profitable for TS inhibitors were explored.Communicated by Ramaswamy H. Sarma.

MAO-B Inhibitor (2E)-3-(4-Bromophenyl)-1-(1H-indol-3-yl) prop-2-en-1-one as a Neuroprotective Agent Against Alzheimer's Disease.

Chalcones (trans-1,3-diphenyl-2-propen-1-ones) form simple chemical structures that act as precursors for the biogenesis of flavonoids. These are distributed in plants and have two aromatic or heteroaromatic rings connected by a three-carbon α, ß-unsaturated carbonyl group. Considering the importance of chalcones as monoamine oxidase and acetylcholinesterase inhibitors, the study was designed as a comprehensive and systematic analysis to evaluate the pharmacological activities leading to the formation of drug molecules against Alzheimer's disease (AD). Based on our previous research, 11 indolyl chalcones (IC1-IC11) were synthesised and investigated for MAO-B inhibitory activity. The inhibitory potential was evaluated based on binding and reversibility studies using purified enzymes. The active and most promising molecule, (2E)-3-(4-bromophenyl)-1-(1H-indol-3-yl) prop-2-en-1-one (IC9), also found predominant acetylcholinesterase inhibition and hence it was found dual acting in vitro. Based on this, the molecule IC9 was further subjected to cell line studies to further explore its role as a neuroprotective agent against neuronal degeneration, one of the main contributing parameters related to AD.

Hesperidin Attenuates Titanium Dioxide Nanoparticle-Induced Neurotoxicity in Rats by Regulating Nrf-2/TNF-α Signaling Pathway, the Suppression of Oxidative Stress, and Inflammation.

Background: Titanium dioxide nanoparticles (TiO2NPs) are widely utilized and consumed mainly as food additives. Oxidative stress is considered to be the basic effect of TiO2NPs through biological interactions. Hesperidin (HSP) is a bioflavonoid (flavanone glycoside) with lipid-lowering, inflammation, oxidative stress suppression, antihypertensive, cancer-fighting, and antiedema effects. Objective: This study was to investigate the possible protective influences of HSP of subchronic oral TiO2NP exposure on the brains of rats, including neurotransmitters, oxidative stress/antioxidant parameters, inflammatory markers, and histological changes in the brains of adult male albino rats. Methodology: The experiment was executed on 80 albino rats. The animals were randomly divided into 4 equal groups. The first group served as a control; the second group was treated with oral doses of HSP (100 mg/kg Bw daily); the third group received TiO2NPs (200 mg/kg Bw orally daily); and the fourth group was treated with TiO2NPs and an oral dose of HSP daily for 8 weeks. Blood samples were obtained for biochemical analysis. Neurotransmitters, oxidative stress biomarker levels, and inflammatory markers were measured in brain homogenates. Histological examination of the brain was performed through H&E staining. Results: Coadministration of hesperidin with TiO2NPs orally for 8 weeks decreased the levels of MDA, TNF-α, AChE, and dopamine in brain homogenates, which were increased in the TiO2NP group. It increased the other oxidative biomarkers (SOD, CAT, and GPx) and Nrf-2 expression levels. Brain histological sections of the TiO2NP-treated group show degeneration, necrosis, congestion, and inflammatory cell infiltration that decreased markedly in the coadministration of hesperidin with the TiO2NP group. Conclusion: Hesperidin cotreatment offers significant protection against TiO2NP-induced oxidative stress and biochemical and histological alteration in the brain.

Effect of nano-encapsulated food flavorings on streptozotocin-induced diabetic rats.

Flavors and aromas are widely used in food and pharmaceutical industries to enhance food palatability. However, it is worth noting that they may also have bioactivity. This study aims to examine the potential impact of key flavors and their nanocapsules on health and diseases, such as type 2 diabetes mellitus (T2DM). The 36 nanocapsules of key flavorings were prepared by high shear homogenization (HSH). Seventy-two male Sprague-Dawley rats received a single dosage of streptozotocin (35 mg kg-1 body weight) intraperitoneally. All of the nutritional and biochemical parameters were statistically analyzed. A virtual docking study was conducted. Linalool nanoemulsion results showed the highest encapsulation efficiency (86.76%), while isoamyl acetate nanoparticles showed the lowest (69.99%). According to GC-MS analysis, encapsulation did not affect the flavoring structure with particle size distributions ranging from 277.3 to 628.8 nm. Using TEM, nanoemulsion particles appeared spherical with a desired nanometric diameter size. In the oral glucose tolerance test, flavorings in oil and nanoforms had no discernible hypoglycemia effects in normal rats. The nutritional and biochemical parameters confirmed that both normal and nanoencapsulation forms demonstrated a potential anti-hyperglycemic effect, and enhanced the rat health compared to the raw flavorings. The studied flavorings and their nanocapsules seem to have the potential double effect of a flavor compound as a food palatability enhancer with a potential beneficial effect on type 2 diabetes mellitus without any health drawbacks.

Corrigendum: Mitigation of acetaminophen-induced liver toxicity by the novel phosphatidylinositol 3-kinase inhibitor alpelisib.

[This corrects the article DOI: 10.3389/fphar.2023.1212771.].

Intranasal Nanotransferosomal Gel for Quercetin Brain Targeting: II. Antidepressant Effect in an Experimental Animal Model.

Depression is a serious mental disorder and the most prevalent cause of disability and suicide worldwide. Quercetin (QER) demonstrated antidepressant effects in rats exhibiting anxiety and depressive-like behaviors. In an attempt to improve QER's antidepressant activity, a QER-loaded transferosome (QER-TFS) thermosensitive gel for intranasal administration was formulated and optimized. The therapeutic effectiveness of the optimized formulation was assessed in a depressed rat model by conducting a behavioral analysis. Behavioral study criteria such as immobility, swimming, climbing, sucrose intake, number of crossed lines, rearing, active interaction, and latency to feed were all considerably enhanced by intranasal treatment with the QER-TFS in situ gel in contrast to other formulations. A nasal histopathological study indicated that the QER-TFS thermosensitive gel was safe for the nasal mucosa. An immunohistochemical analysis showed that the animals treated with the QER-TFS thermosensitive gel had the lowest levels of c-fos protein expression, and brain histopathological changes in the depressed rats were alleviated. According to pharmacodynamic, immunohistochemical, and histopathological experiments, the intranasal administration of the QER-TFS thermosensitive gel substantially alleviated depressive symptoms in rats. However, extensive preclinical investigations in higher animal models are needed to anticipate its effectiveness in humans.

Mitigation of acetaminophen-induced liver toxicity by the novel phosphatidylinositol 3-kinase inhibitor alpelisib.

The sterile inflammatory response mediated by Toll-like receptors (TLRs) 4 and 9 is implicated in the massive hepatic damage caused by acetaminophen (APAP)-overdose. There is a crosstalk between TLR-dependent signaling with other intracellular kinases like phosphatidylinositol 3-kinases (PI3Ks). Nevertheless, the detailed role of PI3Kα is still unknown in hepatic sterile inflammation. Accordingly, the effect of the novel PI3Kα inhibitor alpelisib was investigated in the setting of APAP-driven sterile inflammation in the liver. This was examined by pretreating mice with alpelisib (5 and 10 mg/kg, oral) 2 h before APAP (500 mg/kg, i.p.)-intoxication. The results indicated that alpelisib dose-dependently lowered APAP-induced escalation in serum liver function biomarkers and hepatic necroinflammation score. Alpelisib also attenuated APAP-induced rise in cleaved caspase 3 and proliferating cell nuclear antigen (PCNA) in the liver hepatocytes, as indices for apoptosis and proliferation. Mechanistically, inhibition of PI3Kα by alpelisib limited APAP-induced overproduction of the pro-inflammatory tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and IL-6 in the blood circulation via switching off the activation of several signal transduction proteins, including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription-3 (Stat-3), glycogen Synthase Kinase (GSK)-3ß and nuclear factor (NF)-κB. Alpelisib also impaired APAP-instigated immune cell infiltration in the liver via reducing systemic granulocyte/macrophage-colony stimulating factor (GM-CSF) release and reversed APAP-induced abnormalities in the systemic and hepatic levels of the anti-inflammatory IL-10 and IL-22. In conclusion, selective modulation of the PI3Kα activity by alpelisib can hinder the inflammatory response and infiltration of immune cells occurring by APAP-hepatotoxicity.

Discovery of pyrimidine-tethered benzothiazole derivatives as novel anti-tubercular agents towards multi- and extensively drug resistant Mycobacterium tuberculosis.

In this study, new benzothiazole-pyrimidine hybrids (5a-c, 6, 7a-f, and 8-15) were designed and synthesised. Two different functionalities on the pyrimidine moiety of lead compound 4 were subjected to a variety of chemical changes with the goal of creating various functionalities and cyclisation to further elucidate the target structures. The potency of the new molecules was tested against different tuberculosis (TB) strains. The results indicated that compounds 5c, 5b, 12, and 15 (MIC = 0.24-0.98 µg/mL) are highly active against the first-line drug-sensitive strain of Mycobacterium tuberculosis (ATCC 25177). Thereafter, the anti-tubercular activity was evaluated against the two drug-resistant TB strains; ATCC 35822 and RCMB 2674, where, many compounds exhibited good activity with MIC = 0.98-62.5 3 µg/mL and 3.9-62.5 µg/mL, respectively. Compounds 5c and 15 having the highest anti-tubercular efficiency towards sensitive strain, displayed the best activity for the resistant strains by showing the MIC = 0.98 and 1.95 µg/mL for MDR TB, and showing the MIC = 3.9 and 7.81 µg/mL for XDR TB, consecutively. Finally, molecular docking studies were performed for the two most active compounds 5c and 15 to explore their enzymatic inhibitory activities.

Assembling a Cinnamyl Pharmacophore in the C3-Position of Substituted Isatins via Microwave-Assisted Synthesis: Development of a New Class of Monoamine Oxidase-B Inhibitors for the Treatment of Parkinson's Disease.

Monoamine oxidase (MAO, EC 1.4.3.4) is responsible for the oxidative breakdown of both endogenous and exogenous amines and exists in MAO-A and MAO-B isomers. Eighteen indole-based phenylallylidene derivatives were synthesized via nucleophilic addition reactions comprising three sub-series, IHC, IHMC, and IHNC, and were developed and examined for their ability to inhibit MAO. Among them, compound IHC3 showed a strong MAO-B inhibitory effect with an IC50 (half-maximal inhibitory concentration) value of 1.672 µM, followed by IHC2 (IC50 = 16.934 µM). Additionally, IHC3 showed the highest selectivity index (SI) value of >23.92. The effectiveness of IHC3 was lower than the reference pargyline (0.14 µM); however, the SI value was higher than pargyline (17.16). Structurally, the IHC (-H in the B-ring) sub-series exhibited relatively stronger MAO-B inhibition than the others. In the IHC series, IHC3 (-F in the A-ring) exhibited stronger MAO-B suppression than the other substituted derivatives in the order -F > -Br > -Cl > -OCH3, -CH3, and -H at the 2-position in the A-ring. In the reversibility and enzyme kinetics experiments, IHC3 was a reversible inhibitor with a Ki value of 0.51 ± 0.15 µM for MAO-B. Further, it was observed that IHC3 greatly decreased the cell death caused by rotenone in SH-SY5Y neuroblastoma cells. A molecular docking study of the lead molecule was also performed to determine hypothetical interactions in the enzyme-binding cavity. These findings suggest that IHC3 is a strong, specific, and reversible MAO-B inhibitor that can be used to treat neurological diseases.

Intranasal Nanotransferosomal Gel for Quercetin Brain Targeting: I. Optimization, Characterization, Brain Localization, and Cytotoxic Studies.

Numerous neurological disorders have a pathophysiology that involves an increase in free radical production in the brain. Quercetin (QER) is a nutraceutical compound that shields the brain against oxidative stress-induced neurodegeneration. Nonetheless, its low oral bioavailability diminishes brain delivery. Therefore, the current study aimed to formulate QER-loaded transferosomal nanovesicles (QER-TFS) in situ gel for QER brain delivery via the intranasal route. This study explored the impacts of lipid amount, edge activator (EA) amount, and EA type on vesicle diameter, entrapment, and cumulative amount permeated through nasal mucosa (24 h). The optimum formulation was then integrated into a thermosensitive gel after its physical and morphological characteristics were assessed. Assessments of the optimized QER-TFS showed nanometric vesicles (171.4 ± 3.4 nm) with spherical shapes and adequate entrapment efficiency (78.2 ± 2.8%). The results of short-term stability and high zeta potential value (-32.6 ± 1.4 mV) of QER-TFS confirmed their high stability. Compared with the QER solution, the optimized QER-TFS in situ gel formulation exhibited sustained release behavior and augmented nasal mucosa permeability. CT scanning of rat brains demonstrated the buildup of gold nanoparticles (GNPs) in the brains of all treatment groups, with a greater level of GNPs noted in the rats given the transferosomal gel. Additionally, in vitro studies on PCS-200-014 cells revealed minimal cytotoxicity of QER-TFS in situ gel. Based on these results, the developed transferosomal nanovesicles may be a suitable nanocarrier for QER brain targeting through the intranasal route.