Secondary Metabolites and Their Biological Evaluation from the Aerial Parts of Staehelina uniflosculosa Sibth. & Sm. (Asteraceae).

Phytochemical investigation of Staehelina uniflosculosa Sibth. & Sm. resulted in the isolation of twenty-two natural products: eleven sesquiterpene lactones, artemorin (1), tamirin (2), tanachin (3), reynosin (4), baynol C (5), desacetyl-ß-cyclopyrethrosin (6), 1ß-hydroxy-4α-methoxy-5α,7α,6ß-eudesm-11(13)-en-6,12-olide (7), 1ß,4α,6α-trihydroxyeudesm-11-en-8α,12-olide (8), 1ß-hydroxy-arbusculin A (9), methyl-1ß,4α,6α-trihydroxy-5α,7αH-eudesm-11(13)-en-12-oate (10) and methyl-1ß,6α,8α-trihydroxy-5α,7αH-eudesma-4(15),11(13)-dien-12-oate (11); one lignan, pinoresinol (12); one norisoprenoid, loliolide (13); six flavonoids (four genins and two glycosides), hispidulin (14), nepetin (15), jaceosidin (16), eriodictyol (17), eriodictyol-3'-O-ß-D-glucoside (18) and eriodictyol-7-O-ß-D-glucuronide (19); and three phenolic derivatives (one phenolic acid and two phenolic glucosides), protocatechuic acid (20), arbutin (21) and nebrodenside A (22). From the isolated compounds, only nepetin (15) has been reported previously from the Staehelina genus and, to the best of our knowledge, it is the first time that compound (18) has been identified in Asteraceae. A number of these substances were tested for (a) inhibition of lipoxygenase and acetylocholinesterase, (b) their antioxidant activity using the DPPH (1,1-Diphenyl-2-picrylhydrazyl) method or/and (c) inhibition of lipid peroxidation. The tested components exhibited low antioxidant activity with the exception of 5 and 22, while the effectiveness of these compounds in the inhibition of acetylocholinesterase is limited. Furthermore, Molinspiration, an online computer tool, was used to determine the bioactivity ratings of the isolated secondary metabolites. The compounds' bioactivity ratings for potential therapeutic targets were very promising.

Approaches for the discovery of cinnamic acid derivatives with anticancer potential.

INTRODUCTION: Cinnamic acid is a privileged scaffold for the design of biologically active compounds with putative anticancer potential, following different synthetic methodologies and procedures. Since there is a need for the production of potent anticancer, cinnamate moiety can significantly contribute in the design of new and more active anticancer agents. AREAS COVERED: In this review, the authors provide a review on the synthetic approaches for the discovery of cinnamic acid derivatives with anticancer potential. Results from molecular simulations, hybridization, and chemical derivatization along with biological experiments in vitro and structural activity relationships are given, described, and discussed by the authors. Information for the mechanism of action is taken from original literature sources. EXPERT OPINION: The authors suggest that (i) numerous areas of biology-pharmacology need to be considered: selectivity, in vivo studies, toxicity and drug-likeness, the mechanism of action in animals and humans, development of more efficient assays for various cancer types; (ii) hybridization techniques outbalance in the discovery and production of compounds with higher activity and greater selectivity; (iii) repositioning offers new anticancer cinnamic agents.

Synthesis and Antioxidant Activity of N-Benzyl-2-[4-(aryl)-1H-1,2,3-triazol-1-yl]ethan-1-imine Oxides.

The synthesis, antioxidant capacity, and anti-inflammatory activity of four novel N-benzyl-2-[4-(aryl)-1H-1,2,3-triazol-1-yl]ethan-1-imine oxides 10a-d are reported herein. The nitrones 10a-d were tested for their antioxidant properties and their ability to inhibit soybean lipoxygenase (LOX). Four diverse antioxidant tests were used for in vitro antioxidant assays, namely, interaction with the stable free radical DPPH (1,1-diphenyl-2-picrylhydrazyl radical) as well as with the water-soluble azo compound AAPH (2,2'-azobis(2-amidinopropane) dihydrochloride), competition with DMSO for hydroxyl radicals, and the scavenging of cationic radical ABTS•+ (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical cation). Nitrones 10b, 10c, and 10d, having the 4-fluorophenyl, 2,4-difluorophenyl, and 4-fluoro-3-methylphenyl motif, respectively, exhibited high interaction with DPPH (64.5-81% after 20 min; 79-96% after 60 min), whereas nitrone 10a with unfunctionalized phenyl group showed the lowest inhibitory potency (57% after 20 min, 78% after 60 min). Nitrones 10a and 10d, decorated with phenyl and 4-fluoro-3-methylphenyl motif, respectively, appeared the most potent inhibitors of lipid peroxidation. The results obtained from radical cation ABTS•+ were not significant, since all tested compounds 10a-d showed negligible activity (8-46%), much lower than Trolox (91%). Nitrone 10c, bearing the 2,4-difluorophenyl motif, was found to be the most potent LOX inhibitor (IC50 = 10 µM).

Pharmacochemical Study of Multitarget Amino Acids' Hybrids: Design, Synthesis, In vitro, and In silico Studies.

INTRODUCTION: Neuro-inflammation is a complex phenomenon resulting in several disorders. ALOX-5, COX-2, pro-inflammatory enzymes, and amino acid neurotransmitters are tightly correlated to neuro-inflammatory pathologies. Developing drugs that interfere with these targets will offer treatment for various diseases. OBJECTIVE: Herein, we extend our previous research by synthesizing a series of multitarget hybrids of cinnamic acids with amino acids recognized as neurotransmitters. METHODS: The synthesis was based on an In silico study of a library of cinnamic amide hybrids with glycine, γ- aminobutyric, and L - glutamic acids. Drug-likeness and ADMET properties were subjected to In silico analysis. Cinnamic acids were derived from the corresponding aldehydes by Knoevenagel condensation. The synthesis of the amides followed a two-step reaction with 1- hydroxybenzotriazole monohydrate and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride in dry dichloromethane and the corresponding amino acid ester hydrochloride salt in the presence of N,N,-diisopropyl-Nethylamine. RESULTS: The structure of the synthesized compounds was confirmed spectrophotometrically. The new compounds, such as lipoxygenase, cyclooxygenase-2, lipid peroxidation inhibitors, and antiinflammatories, were tested in vitro. The compounds exhibited LOX inhibition with IC50 values in the low µM region). CONCLUSION: Compounds 18a, 23b, and 11c are strong lipid peroxidation inhibitors (99%, 78%, and 92%). Compound 28c inhibits SLOX-1 with IC50 =8.5 µM whereas 11a and 22a highly inhibit COX-2 (IC50 6 and 5 µM Hybrids 14c and 17c inhibit both enzymes. Compound 29c showed the highest anti-inflammatory activity (75%). The In silico ADMET properties of 14c and 11a support their drug-likeness.

Synthesis, antioxidant and neuroprotective analysis of diversely functionalized α-aryl-N-alkyl nitrones as potential agents for ischemic stroke therapy.

Herein, we report the synthesis, antioxidant and biological evaluation of 32 monosubstituted α-arylnitrones derived from α-phenyl-tert-butyl nitrone (PBN) in the search for neuroprotective compounds for ischemic stroke therapy, trying to elucidate the structural patterns responsible for their neuroprotective activity. Not surprisingly, the N-tert-butyl moiety plays beneficious role in comparison to other differently N-substituted nitrone groups. It seems that electron donor substituents at the ortho position and electron withdrawing substituents at the meta position of the aryl ring induce good neuroprotective activity. As a result, (Z)-N-tert-butyl-1-(2-hydroxyphenyl)methanimine oxide (21a) and (Z)-N-tert-butyl-1-(2-(prop-2-yn-1-yloxy)phenyl)methanimine oxide (24a) showed a significant increase in neuronal viability in an experimental ischemia model in primary neuronal cultures, and induced neuroprotection and improved neurodeficit score in an in vivo model of transient cerebral ischemia. These results showed that nitrones 21a and 24a are new effective small and readily available antioxidants, and suitable candidates for further structure optimization in the search for new phenyl-derived nitrones for the treatment of ischemic stroke and related diseases.

QSAR Studies of Nitric Oxide Synthase Inhibitors.

BACKGROUND: Nitric oxide is a free radical bioregulator controlling homeostasis, vasodilation, and inhibition of platelet aggregation, significantly implicated in the nervous and immune system functionality. In vivo it is produced by nitric oxide synthases (NOSs). OBJECTIVE: Overproduction of nitric oxide is linked to several inflammatory, immunological, and neurodegenerative diseases and for that, various compounds have been synthesized as inhibitors of NOSs. In this review, the QSAR analyses were summarized in a variety of compounds as potent inhibitors of NOSs, and the models derived through 1D, 2D and 3D QSAR analyses. CONCLUSION: Ten groups of various NOS inhibitors and 17 1D, 2D, and 3D QSAR models and analyses were presented and discussed. A lack of hydrophobic terms was noticed in most of the cases. Chemical substituents were selected considering the increase either of the hydrophilicity and/or of hydrophobicity, bulkiness supported steric interactions, and point to potent inhibitors. CMR (Calculated Molar Refractivity) a steric variable, with a negative sign, underlines the critical effects participating on (in) an active site on the enzymes. Indicator variables imply the influence of specific structural moieties. Electronic parameters were found to be significant.

Development of Novel Pyrrole Derivatives and Their Cinnamic Hybrids as Dual COX-2/LOX Inhibitors.

Molecular hybridization has emerged as a promising approach in the treatment of diseases exhibiting multifactorial etiology. With regard to this, dual cyclooxygenase-2/lipoxygenase (COX-2/LOX) inhibitors could be considered a safe alternative to traditional non-steroidal anti-inflammatory drugs (tNSAIDs) and selective COX-2 inhibitors (coxibs) for the treatment of inflammatory conditions. Taking this into account, six novel pyrrole derivatives and pyrrole-cinnamate hybrids were developed as potential COX-2 and soybean LOX (sLOX) inhibitors with antioxidant activity. In silico calculations were performed to predict their ADMET (absorption, distribution, metabolism, excretion, toxicity) properties and drug-likeness, while lipophilicity was experimentally determined as RM values. All synthesized compounds (1-4, 5-8) could be described as drug-like. The results from the docking studies on COX-2 were in accordance with the in vitro studies. According to molecular docking studies on soybean LOX, the compounds displayed allosteric interactions with the enzyme. Pyrrole 2 appeared to be the most potent s-LOX inhibitor (IC50 = 7.5 µM). Hybrids 5 and 6 presented a promising combination of in vitro LOX (IC50 for 5 = 30 µM, IC50 for 6 = 27.5 µM) and COX-2 (IC50 for 5 = 0.55 µM, IC50 for 6 = 7.0 µM) inhibitory activities, and therefore could be used as the lead compounds for the synthesis of more effective multi-target agents.

Thiocarbohydrazone and Chalcone-Derived 3,4-Dihydropyrimidinethione as Lipid Peroxidation and Soybean Lipoxygenase Inhibitors.

The potential of the 4,6-diphenyl-3,4-dihydropyrimidine-2(1H)-thione (abbreviated as KKII5) and (E)-N'-benzylidenehydrazinecarbothiohydrazide (abbreviated as DKI5) compounds as possible drug leads is investigated. KKII5 and DKI5 are synthesized in high yield of up to 97%. Their structure, binding in the active site of the LOX-1 enzyme, and their toxicity are studied via joint experimental and computational methodologies. Specifically, the structure assignment and conformational analysis were achieved by applying homonuclear and heteronuclear 2D nuclear magnetic resonance (NMR) spectroscopy (2D-COSY, 2D-NOESY, 2D-HSQC, and 2D-HMBC) and density functional theory (DFT). The obtained DFT lowest energy conformers were in agreement with the NOE correlations observed in the 2D-NOESY spectra. Additionally, docking and molecular dynamics simulations were performed to discover their ability to bind and remain stabile in the active site of the LOX-1 enzyme. These in silico experiments and DFT calculations indicated favorable binding for the enzyme under study. The strongest binding energy, -9.60 kcal/mol, was observed for dihydropyrimidinethione KKII5 in the active site of LOX-1. ADMET calculations showed that the two molecules lack major toxicities and could serve as possible drug leads. The redox potential of the active center of LOX-1 with the binding molecules was calculated via DFT methodology. The results showed a significantly smaller energy attachment of 2.8 eV with KKII5 binding in comparison to DKI5. Thus, KKII5 enhanced the ability of the active center to receive electrons compared to DKI5. This is related to the stronger binding interaction of KKII5 relative to that of DK15 to LOX-1. The two very potent LOX-1 inhibitors exerted IC50 19 µΜ (KKII5) and 22.5 µΜ (DKI5). Furthermore, they both strongly inhibit lipid peroxidation, namely, 98% for KKII5 and 94% for DKI5.

Exploring the Medicinal Potential of Achillea grandifolia in Greek Wild-Growing Populations: Characterization of Volatile Compounds, Anti-Inflammatory and Antioxidant Activities of Leaves and Inflorescences.

Various species of the genus Achillea L. (Asteraceae) are traditionally used worldwide for wound healing against diarrhea, flatulence, and abdominal pains, as diuretic and emmenagogue agents. In the present study, the essential oils (EOs) obtained separately from the leaves and inflorescences of wild-growing Achillea grandifolia Friv. from Mt. Menoikio and Mt. Pelion (Greece) were analyzed by Gas Chromatography-Mass Spectrometry. The major compounds found in EOs of A. grandifolia inflorescences from Mt. Menoikio were as follows: cis-thujone (36.9%), 1,8-cineole (11.9%), camphor (10.0%), ascaridole (7.3%), α-terpinene (6.4%), sabinene (4.1%), trans-thujone (3.6%), and cis-jasmone (3.4%). In leaves from Mt. Menoikio, they were as follows: cis-thujone (50.8%), 1,8-cineole (20.0%), trans-thujone (5.5%), camphor (5.5%), borneol (3.6%), and α-terpineol (3.1%). In inflorescences from Mt. Pelion, they were as follows: camphor (70.5%), camphene (5.9%), cis-jasmone (3.2%), bornyl acetate (3.2%). In leaves from Mt. Pelion, they were as follows: camphor (83.2%), camphene (3.9%), and borneol (3.7%). Subsequently, the samples were first time tested for their antioxidant activities with the interaction of EOs with DPPH (2,2-diphenyl-1-picrylhydrazyl) and their inhibition of lipid peroxidation, as well as for their anti-inflammatory activity through the soybean LOX (lipoxygenase) inhibition. All of the examined samples were found effective. A. grandifolia leaves presented the highest antioxidant potential according to the DPPH method, and the highest percentage of LOX inhibition. The study herein investigated for the first time the leaves and the inflorescences of A. grandifolia separately, and the results generally align with similar studies from neighboring countries (Turkey and Serbia) in terms of the yields and categorization of main EO compounds (oxygenated monoterpenes). However, the findings were not in agreement with previously studied Greek material, as a higher amount of cis-thujone and lower antioxidant activity are reported herein. Both the EOs of inflorescences and the leaves of the wild-growing population collected from Mt. Menoikio were characterized by a high quantity of cis-thujone (36.9% and 50.8%, respectively).

Optimizing the Distillation of Greek Oregano-Do Process Parameters Affect Bioactive Aroma Constituents and In Vitro Antioxidant Activity?

The aim of the present work was to optimize the conditions of the distillation process at a pilot scale to maximize the yield of specific bioactive compounds of the essential oil of oregano cultivated in Greece, and subsequently to study the in vitro antioxidant activity of these oils. Steam distillation was conducted at an industrial distillery and a Face-Centered Composite (FCC) experimental design was applied by utilizing three distillation factors: time, steam pressure and temperature. Essential oil composition was determined by static headspace gas chromatography-mass spectrometry (HS-GC/MS). To obtain a comprehensive profile of the essential oils, instrumental parameters were optimized, including sample preparation, incubation conditions, sampling process, injection parameters, column thermal gradient and MS conditions. With the applied GC-MS method, more than 20 volatile compounds were identified in the headspace of the oregano essential oils and their relative percentages were recorded. Carvacrol was the most prominent constituent under all distillation conditions applied. Data processing revealed time as the main factor which most affected the yield. The Desired Space (DSc) was determined by conducting a three-dimensional response surface analysis of the independent and dependent variables, choosing yields of thymol and carvacrol as optimization criteria. The in vitro antioxidant activity of the essential oils of all samples was measured in terms of the interaction with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) after 20 and 60 min. The most prominent essential oils at different distillation conditions were also tested as inhibitors of lipid peroxidation. Higher % values of carvacrol and thymol were correlated to higher antioxidant activity. Evaluating the impact of the distillation conditions on the in vitro results, it seems that lower pressure, less time and higher temperature are crucial for enhanced antioxidant activities.

Neuroprotective and antioxidant properties of new quinolylnitrones in in vitro and in vivo cerebral ischemia models.

Cerebral ischemia is a condition affecting an increasing number of people worldwide, and the main cause of disability. Current research focuses on the search for neuroprotective drugs for its treatment, based on the molecular targets involved in the ischemic cascade. Nitrones are potent antioxidant molecules that can reduce oxidative stress. Here we report the neuroprotective properties and the antioxidant power of the six new quinolylnitrones (QNs) 1-6 for their potential application in stroke therapy. QNs 1-4 are 2-chloro-8-hydroxy-substituted QNs bearing N-t-butyl or N-benzyl substituents at the nitrone motif located at C3, whereas QN5 and QN6 are 8-hydroxy QNs bearing N-t-butyl or N-benzyl substituents at the nitrone motif located at C2, respectively. In vitro neuroprotection studies using QNs 1-6 in an oxygen-glucose-deprivation model of cerebral ischemia, in human neuroblastoma cell cultures, indicate that all QNs have promising neuroprotective, anti-necrotic, anti-apoptotic, and anti-oxidant properties against experimental ischemia-reperfusion in neuronal cultures. QN6 stands out as the most balanced nitrone out of all tested QNs, as it strongly prevents decreased neuronal metabolic activity (EC50 = 3.97 ± 0.78 µM), as well as necrotic (EC50 = 3.79 ± 0.83 µM) and apoptotic cell death (EC50 = 3.99 ± 0.21 µM). QN6 showed high capacity to decrease superoxide production (EC50 = 3.94 ± 0.76 µM), similar to its parent molecule α-phenyl-tert-butyl nitrone (PBN) and the well-known anti-oxidant molecule N-acetyl-L-cysteine (NAC). Thus, QN6 demonstrated the highest antioxidant power out of the other tested QNs. Finally, in vivo treatment with QN6 in an experimental permanent stroke model elicited a significant reduction (75.21 ± 5.31%) of the volume size of brain lesion. Overall, QN6 is a potential agent for the therapy of cerebral ischemia that should be further investigated.

Synthesis, structural characterization and study of antioxidant and anti-PrPSc properties of flavonoids and their rhenium(I)-tricarbonyl complexes.

This study aims at the synthesis and initial biological evaluation of novel rhenium-tricarbonyl complexes of 3,3',4',5,7-pentahydroxyflavone (quercetin), 3,7,4΄-trihydroxyflavone (resokaempferol), 5,7-dihydroxyflavone (chrysin) and 4΄,5,7-trihydroxyflavonone (naringenin) as neuroprotective and anti-PrP agents. Resokaempferol was synthesized from 2,2΄,4-trihydroxychalcone by H2O2/NaOH. The rhenium-tricarbonyl complexes of the type fac-[Re(CO)3(Fl)(sol)] were synthesized by reacting the precursor fac-[Re(CO)3(sol)3]+ with an equimolar amount of the flavonoids (Fl) quercetin, resokaempferol, chrysin and naringenin and the solvent (sol) was methanol or water. The respective Re-flavonoid complexes were purified by semi-preparative HPLC and characterized by spectroscopic methods. Furthermore, the structure of Re-chrysin was elucidated by X-ray crystallography. Initial screening of the neuroprotective properties of these compounds included the in vitro assessment of the antioxidant properties by the DPPH assay as well as the anti-lipid peroxidation of linoleic acid in the presence of AAPH and their ability to inhibit soybean lipoxygenase. From the above studies, it was concluded that the complexes' properties are mainly correlated with the structural characteristics and the presence of the flavonoids. The flavonoids and their respective Re-complexes were also tested in vitro for their ability to inhibit the formation and aggregation of the amyloid-like abnormal prion protein, PrPSc, by employing the real-time quaking-induced conversion assay with recombinant PrP seeded with cerebrospinal fluid from patients with Creutzfeldt-Jakob disease. All the compounds blocked de novo abnormal PrP formation and aggregation.

Polyfunctionalized α-Phenyl-tert-butyl(benzyl)nitrones: Multifunctional Antioxidants for Stroke Treatment.

Nowadays, most stroke patients are treated exclusively with recombinant tissue plasminogen activator, a drug with serious side effects and limited therapeutic window. For this reason, and because of the known effects of oxidative stress on stroke, a more tolerable and efficient therapy for stroke is being sought that focuses on the control and scavenging of highly toxic reactive oxygen species by appropriate small molecules, such as nitrones with antioxidant properties. In this context, herein we report here the synthesis, antioxidant, and neuroprotective properties of twelve novel polyfunctionalized α-phenyl-tert-butyl(benzyl)nitrones. The antioxidant capacity of these nitrones was investigated by various assays, including the inhibition of lipid peroxidation induced by AAPH, hydroxyl radical scavenging assay, ABTS+-decoloration assay, DPPH scavenging assay, and inhibition of soybean lipoxygenase. The inhibitory effect on monoamine oxidases and cholinesterases and inhibition of ß-amyloid aggregation were also investigated. As a result, (Z)-N-benzyl-1-(2-(3-(piperidin-1-yl)propoxy)phenyl)methanimine oxide (5) was found to be one of the most potent antioxidants, with high ABTS+ scavenging activity (19%), and potent lipoxygenase inhibitory capacity (IC50 = 10 µM), selectively inhibiting butyrylcholinesterase (IC50 = 3.46 ± 0.27 µM), and exhibited neuroprotective profile against the neurotoxicant okadaic acid in a neuronal damage model. Overall, these results pave the way for the further in-depth analysis of the neuroprotection of nitrone 5 in in vitro and in vivo models of stroke and possibly other neurodegenerative diseases in which oxidative stress is identified as a critical player.

Synthesis and Antioxidant Properties of HeteroBisNitrones Derived from Benzene Dicarbaldehydes.

We report herein the synthesis and antioxidant profile of nine novel heterobisnitrones (hBNs) as new α-phenyl-tert-butylnitrone (PBN) analogues. The synthesized hBNs 1-9 were evaluated for their antioxidant activity using different in vitro techniques, while they were also tested as inhibitors of soybean LOX, as an indication of their anti-inflammatory effect. Nitrone hBN9 is the most potent antioxidant presenting higher anti-lipid peroxidation and hydroxyl radicals scavenging activities as well as higher lipoxygenase inhibition. In silico calculations reveal that hBN9 follows Lipinski's rule of five and that the molecule is able to penetrate theoretically the brain. All these results led us to propose hBN9 as a new potent antioxidant nitrone.

The Prophylactic and Multimodal Activity of Two Isatin Thiosemicarbazones against Alzheimer's Disease In Vitro.

Alzheimer's disease (AD) is a multifactorial disorder strongly involving the formation of amyloid-ß (Aß) oligomers, which subsequently aggregate into the disease characteristic insoluble amyloid plaques, in addition to oxidative stress, inflammation and increased acetylcholinesterase activity. Moreover, Aß oligomers interfere with the expression and activity of Glycogen synthase kinase-3 (GSK3) and Protein kinase B (PKB), also known as AKT. In the present study, the potential multimodal effect of two synthetic isatin thiosemicarbazones (ITSCs), which have been previously shown to prevent Aß aggregation was evaluated. Both compounds resulted in fully reversing the Aß-mediated toxicity in SK-NS-H cells treated with exogenous Aß peptides at various pre-incubation time points and at 1 µM. Cell survival was not recovered when compounds were applied after Aß cell treatment. The ITSCs were non-toxic against wild type and 5xFAD primary hippocampal cells. They reversed the inhibition of Akt and GSK-3ß phosphorylation in 5xFAD cells. Finally, they exhibited good antioxidant potential and moderate lipoxygenase and acetylcholinesterase inhibition activity. Overall, these results suggest that isatin thiosemicarbazone is a suitable scaffold for the development of multimodal anti-AD agents.

Nucleobase-Derived Nitrones: Synthesis and Antioxidant and Neuroprotective Activities in an In Vitro Model of Ischemia-Reperfusion.

Herein, we report the synthesis, antioxidant, and neuroprotective properties of some nucleobase-derived nitrones named 9a-i. The neuroprotective properties of nitrones, 9a-i, were measured against an oxygen-glucose-deprivation in vitro ischemia model using human neuroblastoma SH-SY5Y cells. Our results indicate that nitrones, 9a-i, have better neuroprotective and antioxidant properties than α-phenyl-N-tert-butylnitrone (PBN) and are similar to N-acetyl-L-cysteine (NAC), a well-known antioxidant and neuroprotective agent. The nitrones with the highest neuroprotective capacity were those containing purine nucleobases (nitrones 9f, g, B = adenine, theophylline), followed by nitrones with pyrimidine nucleobases with H or F substituents at the C5 position (nitrones 9a, c). All of these possess EC50 values in the range of 1-6 µM and maximal activities higher than 100%. However, the introduction of a methyl substituent (nitrone 9b, B = thymine) or hard halogen substituents such as Br and Cl (nitrones 9d, e, B = 5-Br and 5-Cl uracil, respectively) worsens the neuroprotective activity of the nitrone with uracil as the nucleobase (9a). The effects on overall metabolic cell capacity were confirmed by results on the high anti-necrotic (EC50's ≈ 2-4 µM) and antioxidant (EC50's ≈ 0.4-3.5 µM) activities of these compounds on superoxide radical production. In general, all tested nitrones were excellent inhibitors of superoxide radical production in cultured neuroblastoma cells, as well as potent hydroxyl radical scavengers that inhibit in vitro lipid peroxidation, particularly, 9c, f, g, presenting the highest lipoxygenase inhibitory activity among the tested nitrones. Finally, the introduction of two nitrone groups at 9a and 9d (bis-nitronas 9g, i) did not show better neuroprotective effects than their precursor mono-nitrones. These results led us to propose nitrones containing purine (9f, g) and pyrimidine (9a, c) nucleobases as potential therapeutic agents for the treatment of cerebral ischemia and/or neurodegenerative diseases, leading us to further investigate their effects using in vivo models of these pathologies.

N-Acylated and N-Alkylated 2-Aminobenzothiazoles Are Novel Agents That Suppress the Generation of Prostaglandin E2.

The quest for novel agents to regulate the generation of prostaglandin E2 (PGE2) is of high importance because this eicosanoid is a key player in inflammatory diseases. We synthesized a series of N-acylated and N-alkylated 2-aminobenzothiazoles and related heterocycles (benzoxazoles and benzimidazoles) and evaluated their ability to suppress the cytokine-stimulated generation of PGE2 in rat mesangial cells. 2-Aminobenzothiazoles, either acylated by the 3-(naphthalen-2-yl)propanoyl moiety (GK510) or N-alkylated by a chain carrying a naphthalene (GK543) or a phenyl moiety (GK562) at a distance of three carbon atoms, stand out in inhibiting PGE2 generation, with EC50 values ranging from 118 nM to 177 nM. Both GK510 and GK543 exhibit in vivo anti-inflammatory activity greater than that of indomethacin. Thus, N-acylated or N-alkylated 2-aminobenzothiazoles are novel leads for the regulation of PGE2 formation.

Chemical constituents isolated from the aerial parts of Helleborus cyclophyllus (A. Braun) Boiss. (Ranunculaceae), evaluation of their antioxidant and anti-inflammatory activity in vitro and virtual screening of molecular properties and bioactivity score.

Chemical investigation of ethyl acetate extract from the aerial parts of Helleborus cyclophyllus (A.Braun) Boiss. led to the isolation of ten natural products, and their structures were identified to be: 2-deoxy-D-ribono-1,4-lactone (1), 2-O-feruloyl-L-malate (2), three flavonoids: quercetin 3-O-ß-D-galactopyranoside (3), quercetin 3-O-6''-(3-hydroxy-3-methyl-gloutaryl)-ß-D-glucopyranoside (4) and quercetin 3-O-(2‴-caffeoylsophoroside) (5), 6-O-caffeoyl-1-O-p-coumaroyl-ß-D-glucopyranoside (6), two ecdysteroids: 20-hydroxyecdysone (7) and polypodine B (8) and two bufadienolides: deglucohellebrin (9) and hellebrin (10), on the basis of MS and NMR spectra. This is the first report on the occurrence of compounds (2)-(6) in the genus Helleborus. The chemotaxonomic significance of these compounds was summarised. Bioactivity score, molecular and pharmacokinetic properties of the isolated compounds were calculated by online computer software program Molinspiration. Compounds showed promising bioactivity scores for drug targets. Moreover, some of the isolated phenolic compounds were tested for their antioxidant and antiinflammatory activities. Tested compounds presented antioxidant ability correlated to the presence of the phenolic hydroxyl groups.

Synthesis and Antioxidant Properties of Novel 1,2,3-Triazole-Containing Nitrones.

Herein, we report the synthesis and antioxidant capacity of twelve novel 1,2,3-triazole-containing nitrones such as N-(2-(4-aryl-1H-1,2,3-triazol-1-yl)ethylidene)methanamine oxides 8a-f and N-(2-(4-aryl)-1H-1,2,3-triazol-1-yl)ethylidene)-2-methylpropan-2-amine oxides 9a-f, bearing an N-methyl, and an N-t-butyl substituent, respectively, at the nitrogen of the nitrone motif. Nitrones 8 and 9 were studied with regard to their antioxidant ability, as well as their ability to inhibit soybean lypoxygenase (LOX), and their in vitro antioxidant activity. For this, we used three different antioxidant assays, such as that featuring the interaction with the water-soluble azo compound AAPH for the inhibition of lipid peroxidation (LP), the competition with the DMSO for scavenging hydroxyl radicals, and the ABTS•+-decolorization assay. t-Butyl nitrone 9e, bearing the 2,4-difluorophenyl motif, showed a strong LP inhibitory effect (100%), close to the reference compound Trolox (93%), being the most potent LP inhibitor (LPi) of the whole series of tested nitrones. Nitrones 9d, 9e and 9f, bearing the 4-fluorophenyl, 2,4-difluorophenyl, and 4-fluoro-3-methylphenyl motif, respectively, were almost equipotent, and the most potent hydroxyl radical scavengers (~100%), more potent than Trolox (88%), were used as a reference compound. Regarding the LOX inhibition, the most potent inhibitor was the t-butyl substituted nitrone 9f (27 µM), bearing the 4-fluoro-3-methylphenyl motif, being 60-fold less potent than NDGA (0.45 µM), which was used as the standard in this test. The results from the antioxidant determination in the ABTS radical cation (ABTS•+) decolorization assay were not significant. N-Methyl nitrone 8f, bearing the 4-fluoro-3-methylphenyl motif, was the only promising representative, with a value of 34.3%, followed by nitrone 9f (16%). From the antioxidant analyses, we have identified N-(2-(4-(4-fluoro-3-methylphenyl)-1H-1,2,3-triazol-1-yl)ethylidene)-2-methylpropan-2-amine oxide (9f), bearing t-butyl and 4-fluoro-3-methylphenyl motifs in its structure, as the most balanced and potent antioxidant agent among the tested nitrones, as it was the most potent LOX inhibitor (27 µM), an extremely efficient and potent hydroxyl radical scavenger (99.9%), as well as one of the most potent LPi (87%) and ABTS•+ scavengers (16%).

Community Attitudes and Habits Toward Over-The-Counter Drugs: Results of a Study Conducted in Thessaloniki, Greece.

OBJECTIVES: To determine the frequency of use, sources of information, and selection criteria of Greek residents regarding over-the-counter (OTC) drugs, as well as their opinion about their dispensing in nonpharmacy settings. METHODS: This was a survey study in which an anonymous cross-sectional questionnaire was used to assess the knowledge, habits, and attitudes about OTC drugs. Data were collected from March 2017 to July 2017 in Thessaloniki, the second largest city in Greece. Logistic regression was used to investigate significant factors that affect the participants' behavior. RESULTS: A total of 782 participants completed the questionnaire. The population had a mean (SD) age of 46 (17) years and 55.1% were females. About one-third (32.5%) of the participants used nonsteroidal anti-inflammatory drugs more than once per week. OTC drugs acting on the gastrointestinal tract were used to a lower extent (13.2%). The majority (84%) of the respondents consult a healthcare professional about the information on OTC drugs. Furthermore, when not sure about which OTC drug to use, 510 participants (65.6%) valued their physician's advice, whereas 480 participants (60.2%) valued their pharmacist's advice. Most participants (61.2%) were negatively inclined toward the purchase of OTC drugs in nonpharmacy settings, with younger participants being more receptive to out-of-pharmacy OTC drug purchase than older ones (odds ratio 2.20; 95% confidence interval 1.37-3.54). CONCLUSIONS: Healthcare professionals play an important role in providing people information on their selection of OTC drugs. This could be the main reason why participants prefer to buy OTC drugs from community pharmacies rather than retail shops.