Anticonvulsive profile of two GABAB receptor antagonists on acute seizure mice models.

INTRODUCTION: DL-3-hydroxy-3-phenylpentanamide (HEPP) and DL-3-hydroxy-3-(4'chlorophenyl)-pentanamide (Cl-HEPP) are phenyl-alcohol-amides that are metabotropic GABAB receptor (MGBR) antagonists and protective against absence seizures. This study aims to further characterize the anticonvulsant profile of these drugs. METHODS: HEPP and Cl-HEPP were evaluated in various standardized acute seizure and toxic tests in female Swiss-OF1 mice. RESULTS: Toxicities of HEPP and Cl-HEPP were limited; doses up to 30 mg/kg did not result in hypothermia, reduced spontaneous locomotor activity, or failure of the rotarod test, with doses >15 mg/kg potentiating pentobarbital-induced sleep. In maximal electroshock-induced seizures, 20 mg/kg Cl-HEPP protected 100 % of mice; lower doses shortened post-ictal recovery. Seizure protection occurred against subcutaneous pentylenetetrazole and picrotoxin, being limited against N-methyl-d-aspartate. In bicuculline test, clonic or fatal tonic seizures were decreased, onset delayed, and recovery improved; ED50 values (dose protecting 50 % of the animals) were 37.5 and 25 mg/kg for HEPP and Cl-HEPP, respectively. In magnesium deficiency-dependent audiogenic seizures (MDDAS), ED50 values were 3 and 8 mg/kg for Cl-HEPP and HEPP, respectively. The components of MDDAS (latency, wild running, seizure, and recovery phases) in unprotected animals were only minimally affected by near ED50 doses of Cl-HEPP and HEPP. DISCUSSION: HEPP and, to a greater extent, Cl-HEPP provide anti-seizure protections in several acute seizure tests in mice at nontoxic doses. These results are consistent with the action of these drugs on diverse molecular targets directly resulting from their MGBR antagonistic properties. However, other mechanisms might occur possibly for the protection given in the MES test. Finally, a similarity in the modulation of MDDAS components between the two phenyl alcohol amides and ethosuximide could also be based on the MGBR antagonistic properties of the former, given the recently re-evaluated therapeutic relevant targets of the latter.

Synthesis, molecular docking and biological evaluation of novel phthaloyl derivatives of 3-amino-3-aryl propionic acids as inhibitors of Trypanosoma cruzi trans-sialidase.

In the last two decades, trans-sialidase of Trypanosoma cruzi (TcTS) has been an important pharmacological target for developing new anti-Chagas agents. In a continuous effort to discover new potential TcTS inhibitors, 3-amino-3-arylpropionic acid derivatives (series A) and novel phthaloyl derivatives (series B, C and D) were synthesized and molecular docking, TcTS enzyme inhibition and determination of trypanocidal activity were carried out. From four series obtained, compound D-11 had the highest binding affinity value (-11.1 kcal/mol) compared to reference DANA (-7.8 kcal/mol), a natural ligand for TS enzyme. Furthermore, the 3D and 2D interactions analysis of compound D-11 showed a hydrogen bond, π-π stacking, π-anion, hydrophobic and Van der Waals forces with all important amino acid residues (Arg35, Arg245, Arg314, Tyr119, Trp312, Tyr342, Glu230 and Asp59) on the active site of TcTS. Additionally, D-11 showed the highest TcTS enzyme inhibition (86.9% ±â€¯5) by high-performance ion exchange chromatography (HPAEC). Finally, D-11 showed better trypanocidal activity than the reference drugs nifurtimox and benznidazole with an equal % lysis (63 ±â€¯4 and 65 ±â€¯2 at 10 µg/mL) and LC50 value (52.70 ±â€¯2.70 µM and 46.19 ±â€¯2.36 µM) on NINOA and INC-5 strains, respectively. Therefore, D-11 is a small-molecule with potent TcTS inhibition and a strong trypanocidal effect that could help in the development of new anti-Chagas agents.

Peltomexicanin, a Peltogynoid Quinone Methide from Peltogyne Mexicana Martínez Purple Heartwood.

Peltomexicanin (7,10-dihydroxy-6,12-dioxa-5H-tetraphen-3-one) is a new peltogynoid quinone methide isolated from Palo Morado (Peltogyne mexicana Martínez) heartwood by column chromatography. Its chemical structure was elucidated by IR, NMR (¹H, (13)C), 2D NMR experiments (COSY, NOESY, HMQC, and HSQC), ESI-MS, and UV-Vis spectroscopic analysis. According to HPLC quantification, this compound is the main pigment and accounts for 1.21% of Palo Morado heartwood material. The antioxidant activity of peltomexicanin and dried methanolic extract (DEx) of purple heartwood was evaluated using the radical of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay, and the corresponding values expressed as Trolox equivalents (µmol TE/mg sample) were 4.25 and 4.57, respectively.

Targeting quorum sensing by designing azoline derivatives to inhibit the N-hexanoyl homoserine lactone-receptor CviR: Synthesis as well as biological and theoretical evaluations.

To counteract bacterial resistance, we investigated the interruption of quorum sensing mediated by non-classical bioisosteres of the N-hexanoyl homoserine lactone with an azoline core. For this purpose, a set of selected 2-substituted azolines was synthesized, establishing the basis for a new protocol to synthesize 2-amino imidazolines. The synthesized compounds were evaluated as inhibitors of violacein production in Chromobacterium violaceum. Theoretical studies on bioisostere-protein interactions were performed using CviR. The results show that some azolines decreased violacein production, suggesting an antiquorum sensing profile against Gram-negative bacteria. Docking and molecular dynamic simulations together with binding free energy calculations revealed the exact binding and inhibitory profiles. These theoretical results show relationship with the in vitro activity of the azoline series.

Microwave-assisted solvent-free synthesis and in vitro antibacterial screening of quinoxalines and pyrido[2, 3b]pyrazines.

We report herein the microwave assisted synthesis, without solvents and catalysts, of 6-substituted quinoxalines and 7-substituted pyrido[2,3b]pyrazines. The compounds were obtained in good yields and short reaction times using the mentioned procedure and two new structures are reported. A complete ¹H- and ¹³C-NMR assignment was performed using 1D and 2D-NMR. Additionally, an in vitro screening was performed on Gram-positive and Gram-negative bacteria using amoxicillin as positive reference. Compounds bearing a pyridyl group tended to have higher antibacterial activity, but the best activity against Bacillus subtilis and Proteus mirabilis was observed with quinoxaline derivatives.

Biologically important eremophilane sesquiterpenes from alaska cedar heartwood essential oil and their semi-synthetic derivatives.

The essential oil of Alaska cedar heartwood is known to contain compounds which contribute to the remarkable durability of this species. While previous research has identified several compounds, a complete description of this oil has not been undertaken. In this research a profile of the oil is given in which the major components are identified by GC, isolation and spectroscopic techniques. The major components of the steam distilled essential oil were identified as nootkatin, nootkatone, valencene, nootaktene, carvacrol, methyl carvacrol, nootkatol (2), and eremophil-1(10),11-dien-13-ol (3). The last two compounds were isolated for the first time from Alaska cedar in this research. The absolute stereochemistry at C-2 of nootkatol was shown to have the (S) configuration using the Mosher ester method. Assignment of stereochemistry for valencene-13-ol (3) was established by synthesis from valencene (6). Finally, two related sesquiterpenoids were synthesized from nootkatone and valencene. These sesquiterpenoids were nootkatone-1,10-11,12-diepoxide (5) and valencene-13-aldehyde (4), respectively.

Synthesis of DL-fluorobenzenamides as anticonvulsants.

DL-2-Hydroxy-2-phenyl butyramide (1, CAS 52839-87-9), DL-3-hydroxy-3-phenyl pentanamide (2, CAS 131802-69-2) and DL-4-hydroxy-4-phenyl hexanamide (3, CAS 67880-30-2) are anticonvulsants. Searching for more active compounds, some DL-fluorobenzenamides were prepared and tested: DL-2-hydroxy-2-(3'-trifluoromethylphenyl)butyramide (4), DL-2-Hydroxy-2-4'-trifluoromethylphenyl) butyramide (5, CAS 620950-10-9), DL-2-hydroxy-2-[3',5'-bis(trifluoromethyl)phenyl]butyramide (6, CAS 620950-09-6), DL-3-hydroxy-3-(3'-trifluoromethylphenyl) pentanamide (7), DL-3-hydroxy-3-(4'-trifluoromethylphenyl)pentanamide (8), and DL-3-hydroxy-3-[3',5'-bis(trifluoromethyl)phenyl]pentanamide (9, CAS 863976-07-2). Compounds 4-9 exhibited anticonvulsant activity in seizures induced by pentylenetetrazol in mice. Incorporation of trifluoromethyl groups in the phenyl ring of 1, 2 and 3 increased their potency. Compounds 4, 6 and 9 exhibited a similar anticonvulsant activity as the reference drug phenobarbital (CAS 50-06-6).

Synthesis of DL-hydroxybenzenamides as anticonvulsants.

The anticonvulsant activity of some DL-hydroxybenzenamides is described. The following compounds from this series were prepared and tested: DL-2-hydroxy-2-(3'-bromophenyl)butyramide (4, CAS 620950-12-1), DL-2-hydroxy-2-(4'-bromophenyl)butyramide (5, CAS 620950-13-2), DL-2-hydroxy-2-(3'-nitrophenyl)butyramide (6, CAS 620950-14-3), DL-2-hydroxy-2-phenyl hexanamide (7, CAS 63002-05-1), DL-2-hydroxy-2-(3',4'-dichlorophenyl)hexanamide (8, CAS 863976-06-1), DL-3-hydroxy-3-(4'-bromophenyl)pentanamide (9, CAS 620950-16-5), DL-3-hydroxy-3-phenyl-heptanamide (10, CAS 863976-08-3) and DL-4-hydroxy-4-(4'-bromophenyl)hexanamide (11,CAS 620950-18-7). Compounds 4, 5, 9 and 11 exhibited significant activity in seizures induced by pentylenetetrazol. Incorporation of bromine in the phenyl ring increased their potency. Compounds 4, 5, 9 and 11 exhibited a similar anticonvulsant activity as the reference drug phenobarbital (CAS 50-06-6).

Repellent activity of fractioned compounds from Chamaecyparis nootkatensis essential oil against nymphal Ixodes scapularis (Acari: Ixodidae).

Preliminary repellent activity of 14 natural products isolated from essential oil components extracted from the heartwood of Alaska yellow cedar, Chamaecyparis nootkatensis (D. Don) Spach., were evaluated against nymphal Ixodes scapularis Say in a laboratory bioassay and compared with technical grade N,N-diethyl-3-methylbenzamide (deet). Four hours after treatment, nootkatone and valencene-13-ol had repellent concentration (RC)50 values of 0.0458 and 0.0712% (wt:vol), respectively; two additional Alaska yellow cedar compounds, nootkatone 1 --> 10 epoxide and carvacrol had reported RC50 values of 0.0858 and 0.112%, respectively. The observed RC50 value for deet was 0.0728% (wt:vol). Although not statistically significantly more active than deet, the ability of these natural products to repel ticks at relatively low concentrations may represent a potential alternative to synthetic commercial repellents.

Use of novel compounds for pest control: insecticidal and acaricidal activity of essential oil components from heartwood of Alaska yellow cedar.

Laboratory bioassays were conducted to determine the activity of 15 natural products isolated from essential oil components extracted from the heartwood of Alaska yellow cedar, Chamaecyparis nootkatensis (D. Don) Spach., against Ixodes scapularis Say nymphs, Xenopsylla cheopis (Rothchild), and Aedes aegypti (L.) adults. Four of the compounds from the essential oil have been identified as monoterpenes, five as eremophilane sesquiterpenes, five as eremophilane sesquiterpene derivatives from valencene and nootkatone, and one as a sesquiterpene outside the eremophilane parent group. Carvacrol was the only monoterpene that demonstrated biocidal activity against ticks, fleas, and mosquitoes with LC50 values after 24 h of 0.0068, 0.0059, and 0.0051% (wt:vol), respectively. Nootkatone from Alaska yellow cedar was the most effective of the eremophilane sesquiterpenes against ticks (LC50 = 0.0029%), whereas the nootkatone grapefruit extract exhibited the greatest biocidal activity against fleas (LC50 = 0.0029%). Mosquitoes were most susceptible to one of the derivatives of valencene, valencene-13-aldehyde (LC50 = 0.0024%), after 24 h. Bioassays to determine residual activity of the most effective products were conducted at 1, 2, 4, and 6 wk after initial treatment. Residual LC50 values for nootkatone did not differ significantly at 4 wk posttreatment from the observations made at the initial 24-h treatment. The ability of these natural products to kill arthropods at relatively low concentrations represents an alternative to the use of synthetic pesticides for control of disease vectors.

Neocandenatone, an isoflavan-cinnamylphenol quinone methide pigment from Dalbergia congestiflora.

A purple pigment neocandenatone (vestitol[6-->9";7O-->7"]obtusaquinone) was isolated from the heartwood of campincerán (Dalbergia congestiflora), an endemic Mexican tree. The isoflavan-cinnamyl phenol quinone methide structure of this compound was elucidated by HRMS, IR, and 1H and 13C NMR spectroscopic analysis, including 2D experiments (COSY, NOESY, HMQC and HSQC).

Complete assignment of the 1H, 13C, 15N and 19F NMR spectra of nine DL-phenylalcoholamide anticonvulsants.

The 1H, 13C, 15N and 19F NMR spectra of nine DL-phenylalcoholamides bearing fluorine and chlorine as substituents of the phenyl ring are reported. All of them are active as anticonvulsants in pentylenetetrazole-induced seizures.

Synthesis and pharmacological evaluation of some DL-dichlorophenyl alcohol amides anticonvulsants.

The anticonvulsant activity of a homologous series of DL-dichlorophenyl alcohol amides is described. The compounds DL-2-hydroxy-2-(3',4'-dichlorophenyl) butyramide (4, CAS 620950-11-0), DL-3-hydroxy-3-(3',4'-dichlorophenyl) pentanamide (5, CAS 620950-15-4) and DL-4-hydroxy-4-(3',4'-dichlorophenyl) hexanamide (6, CAS 620950-17-6 ) were prepared and tested. Compounds 4, 5 and 6 exhibited a significant activity in seizures induced by pentetrazol. Incorporation of chlorine in the phenyl ring increased their potency. Compound 4 exhibited a slightly lower activity than the reference drug phenobarbital (CAS 50-06-6).