Investigation of structure−activity relationships for benzoyl and cinnamoyl piperazine/piperidine amides as Tyrosinase inhibitors

Melanin is a substance that plays important roles in several organisms. Its function as an antioxidant and metal-complexing agent makes tyrosinase, the key enzyme that controls melanogenesis, an interesting target for designing inhibitors. In this article, we report a set of piperazine/piperidine amides of benzoic and cinnamic acid derivatives as tyrosinase inhibitors with improved potency and drug-likeness. The most potent compound 5b showed a pIC50 of 4.99 in the monophenolase assay, and only compound 3a showed reasonable potency in the diphenolase assay (pIC50, 4.18). These activities are not correlated to antiradical activity, suggesting that the activity is dependent on competition with the substrates. Molecular docking studies indicated that the benzyl substituent of 5b and other analogues perform important interactions in the enzyme that may explain the higher potency of these compounds. Moreover, the compounds present adequate lipophilicity and skin permeability and no relevant cytotoxicity (CC50 > 200 μM) to mammalian cells.

Pharmacological and SAR analysis of the LINS01 compounds at the human histamine H1 , H2 , and H3 receptors.

Histamine is a transmitter that activates the four receptors H1 R to H4 R. The H3 R is found in the nervous system as an autoreceptor and heteroreceptor, and controls the release of neurotransmitters, making it a potential drug target for neuropsychiatric conditions. We have previously reported that the 1-(2,3-dihydro-1-benzofuran-2-yl)methylpiperazines (LINS01 compounds) have the selectivity for the H3 R over the H4 R. Here, we describe their pharmacological properties at the human H1 R and H2 R in parallel with the H3 R, thus providing a full analysis of these compounds as histamine receptor ligands through reporter gene assays. Eight of the nine LINS01 compounds inhibited H3 R-induced histamine responses, but no inhibition of H2 R-induced responses was seen. Three compounds were weakly able to inhibit H1 R-induced responses. No agonist responses were seen to any of the compounds at any receptor. SAR analysis shows that the N-methyl group improves H3 R affinity while the N-phenyl group is detrimental. The methoxy derivative, LINS01009, had the highest affinity.

Anti-Sporothrix brasiliensis activity of different pyrazinoic acid prodrugs: a repurposing evaluation

From drug repurposing studies, this work aimed to evaluate the activity of different pyrazinoic acid (POA) derivatives against Sporothrix brasiliensis. The POA esters were prepared and characterized as previously reported by classical esterification reactions, with good to excellent yields. Sporothrix brasiliensis isolates from cats (n=6) and standard strains of S. brasiliensis and S. schenckii were used to assess the antifungal activity of the POA derivatives through broth microdilution assay (CLSI M38-A2). Among the tested compounds, molecules 3 and 4 showed fungistatic and fungicidal activities against all Sporothrix spp. strains, and the obtained MIC and MFC values ranged from 2.12 to 4.24 mg/mL and from 1.29 to 5.15 mg/mL, respectively. Compound 2 and 5 were active as in vitro inhibitors of fungal growth, but showed weak fungicidal activity, while molecules 1 and POA itself were inactive. The results suggest the activity of POA derivatives against Sporothrix spp. may be dependent on the lipophilicity. In addition, the antifungal susceptibility of the isolates to itraconazole was performed, showing that two Sporothrix isolates from cats were itraconazole-resistant. Compounds 3 and 4 were also active against these itraconazole-resistant isolates, indicating a possible alternative route to the standard mode of action of itraconazole.

1-[(2,3-Dihydro-1-benzofuran-2-yl) methyl]piperazines as novel anti-inflammatory compounds: Synthesis and evaluation on H3 R/H4 R.

The histamine receptors (HRs) are members of G-protein-coupled receptor superfamily and traditional targets of huge therapeutic interests. Recently, H3 R and H4 R have been explored as targets for drug discovery, including in the search for dual-acting H3 R/H4 R ligands. The H4 R, the most recent histamine receptor, is a promising target for novel anti-inflammatory agents in several conditions such as asthma and other chronic inflammatory diseases. Due to similarity with previously reported ligands of HRs, a set of 1-[(2,3-dihydro-1-benzofuran-2-yl)methyl]piperazines were synthesized and evaluated in competitive binding assays as H3 R/H4 R ligands herein. The results showed the compounds presented affinity (Ki ) for H3 R/H4 R in micromolar range, and they are more selective to H3 R. All the compounds showed no important cytotoxicity to mammalian cells. The phenyl-substituted compound LINS01005 has shown the higher affinity of the set for H4 R, but no considerable selectivity toward this receptor over H3 R. LINS01005 showed interesting anti-inflammatory activity in murine asthma model, reducing the eosinophil counts in bronchoalveolar lavage fluid, as well as the COX-2 expression. The presented compounds are valuable prototypes for further improvements to achieve better anti-inflammatory agents.

Antimycobacterial activity of pyrazinoate prodrugs in replicating and non-replicating Mycobacterium tuberculosis.

Tuberculosis (TB) is an important infectious disease caused by Mycobacterium tuberculosis (Mtb) and responsible for thousands of deaths every year. Although there are antimycobacterial drugs available in therapeutics, just few new chemical entities have reached clinical trials, and in fact, since introduction of rifampin only two important drugs had reached the market. Pyrazinoic acid (POA), the active agent of pyrazinamide, has been explored through prodrug approach to achieve novel molecules with anti-Mtb activity, however, there is no activity evaluation of these molecules against non-replicating Mtb until the present. Additionally, pharmacokinetic must be preliminary evaluated to avoid future problems during clinical trials. In this paper, we have presented six POA esters as prodrugs in order to evaluate their anti-Mtb activity in replicating and non-replicating Mtb, and these showed activity highly influenced by medium composition (especially by albumin). Lipophilicity seems to play the main role in the activity, possibly due to controlling membrane passage. Novel duplicated prodrugs of POA were also described, presenting interesting activity. Cytotoxicity of these prodrugs set was also evaluated, and these showed no important cytotoxic profile.

Pyrazinamide and Pyrazinoic Acid Derivatives Directed to Mycobacterial Enzymes Against Tuberculosis.

Tuberculosis (TB) is an infectious diseases responsible for thousands of deaths worldwide. Due to the use of antimycobacterial drugs, TB prevalence seemed to be controlled, but with the appearance of resistant tuberculosis cases, the concern about the disease had become significant again, as well as the need for new alternatives to TB treatment. Since pyrazinamide (PZA) is part of the firstline agents in TB treatment, several derivatives of this drug were described, besides pyrazinoic acid (POA) derivatives, the active form of PZA. POA has been used mainly to design prodrugs to be activated by mycobacterial esterases, while PZA derivatives should be activated specifically by the nicotinamidase/ pyrazinamidase (PZAse), or other PZAse-independent pathways. The intention of this paper is to discuss the state of art of PZA and POA derivatives and their activity against Mycobacterium tuberculosis and other mycobacteria, besides the therapeutic potential. Focus was given in prodrugs and derivatives directed to mycobacterial enzymes involved in its activation or mechanism of action.

Synthesis and evaluation of a pyrazinoic acid prodrug in Mycobacterium tuberculosis.

Tuberculosis (TB) is a disease caused mainly by infection of Mycobacterium tuberculosis affecting more than ten million people around the world. Despite TB can be treated, the rise of MDR-TB and XDR-TB cases put the disease in a worrying status. As pyrazinamide-resistant strains exhibit low or none pyrazinamidase activity, it is proposed that the active form of pyrazinamide (PZA) is pyrazinoic acid (POA), although this acid has poor penetration in mycobacteria. In this work, we present a convenient one-pot synthesis of 2-chloroethyl pyrazinoate, and its activity in M. tuberculosis H37Rv (ATCC27294) in MIC assay using the MABA technique. The obtained MIC of the compound was 3.96 g/mL, and discussion about the activity profile of some previously evaluated pyrazinoates is also performed.

Cytotoxicity evaluation of Curcuma zedoaria (Christm.) Roscoe fluid extract used in oral hygiene products.

OBJECTIVE: This in vitro study evaluated the cytotoxic effects of the Curcuma zedoaria (Christm.) Roscoe (popular name: zedoary) fluid extract, as used in preparations for oral hygiene, mostly for anti-septic purposes. MATERIALS AND METHODS: The cell viability and cell growth were assessed by Trypan blue dye exclusion assay using the LMF cell line derived from oral mucosa. Cell viability (short-term assay) was measured 0, 6, 12 and 24 h after contact with the fluid extract. Cell growth (long-term assay) was analyzed in 1, 3, 5 and 7 days. The experimental groups were those testing the fluid extract obtained from the zedoary rhizome and the extractor liquid (ethanol 70° GL) in the concentrations of 0.01-0.0001% v/v. Fresh DMEM were used in the control cultures. RESULTS: Short-term assay-all studied cultures maintained stable cell viability; Long-term assay-there was progressive cell growth in all studied cultures. CONCLUSION: According to the results, the zedoary fluid extract presents low cytotoxicity and probably can be used in the oral hygiene products.

Planejamento e sintese de compostos potencialmente ligantes dos receptores 5-HT2C e H4 / Design and synthesis of compounds potentially ligands of 5-HT2C e H4

A serotonina e a histamina são duas das mais importantes aminas biogênicas do organismo. Regulam série de funções fisiológicas, como fluxo sanguíneo, temperatura corpórea, sono, fome, liberação de hormônios, comportamento afetivo e humor, entre outras. Assim, há grande interesse no planejamento e desenvolvimento de fármacos que interferem na transmissão serotoninérgica e histaminérgica, para futura aplicação como antidepressivos, antipsicóticos, ansiolíticos e anorexígenos, além de perifericamente, apresentarem possíveis ações antiinflamatórias. O objetivo deste trabalho é apresentar a síntese de compostos contendo os núcleos pirrolquinolínico, benzoindólico e benzodiidrofurânico com potencial atividade ligante nos receptores 5-HT2C e H4, assim como avaliar a seletividade desses compostos em comparação aos receptores 5-HT2A/B e H3. Sintetizou-se série de compostos utilizando reações de alilação, adição à carbonila, termociclização, rearranjo de Claisen, iodociclização e substituição nucleofílica para a obtenção dos compostos finais. Estudos de otimização de síntese por metodologia de superfície de resposta também são apresentados, assim como estudos de relações quantitativas entre estrutura química e atividade biológica de compostos ligantes dos receptores 5-HT2C e H4

Serotonin and histamine are two major biogenic amines in the body. They regulate several physiological functions such as blood flow, body temperature, sleep, hunger, hormone release, emotional behavior and mood, among others. Thus, there is great interest in the design and development of drugs that interfere with serotoninergic and histaminergic transmission, for future use as antidepressants, antipsychotics, anxiolytics and anorectic, and peripherally, possible anti-inflammatory actions. The aim of this work is to present the synthesis of compounds containing the pyrroloquinoline, benzoindole and benzodihydrofurane nucleus with potential binding activity to 5-HT2C and H4 receptors, as well as to evaluate the selectivity of these compounds in comparison to 5-HT2A/B and H3. Series of compounds were synthesized using allylation, carbonyl addition, thermal cyclization, Claisen rearrangement, iodocyclization and nucleophilic substitution reactions. Optimization studies for the synthesis using response surface methodology are also presented, as well as quantitative structure-activity relationships studies of ligands of 5-HT2C and H4 receptors

Prevalência de disfuncões crânio cervicais em pacientes portadores de disfunções temporomandibulares / Prevalence of cranio spine difunction in patients with temporomandibular difunction

O presente estudo teve como objetivos determinar a prevalência de Disfunções Crânio Cervicais (DCC) em voluntários portadores de Disfunções Temporomandibulares (DTM). Foram se¬lecionados 200 voluntários do serviço de triagem da Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas, os quais foram avaliados por meio da ficha clínica ela¬borada pelo Centro de Estudos e Tratamento das Alterações Funcionais do Sistema Estomatognático (CETASE) para o diagnóstico de DTM. Os voluntários que apresentaram sinais e síntomas positivos para as DTM foram submetidos a um novo exame clínico para avaliação de DCC. Os resultados obtidos demonstraram uma prevalência de 69% de DCC em voluntários portadores de DTM. Os sinais e sintomas de maior prevalência para as duas patologias foram presença de ruído articular, dor nas articulações tem poro mandibulares e dor à palpação nos músculos mas¬seter e trapézio. Em conclusão, devido à significante prevalência da associação entre DCC e DTM se torna importante a investigação clínica das estruturas cervicais durantes os exames físicos para o diagnóstico das DTM.

The objective of the present study was to determine the prevalence of Cervical Spine Disfunction (CSD) in volunteers with Temporomandibular Disfunction (TMD). 200 volunteers were selected from the screening service of Dentistry School of Piracicaba, State University of Campinas, which were evaluated by records prepared by the Center for Research and Treatment of Functional Alterations of the Stomatognathic System (CETASE) for the diagnosis of TMD. Volunteers who presented positive signs and symptoms of TMD underwent a new clinical examination for C5D. The results showed a prevalence of 69% of CSD in volunteers with TMD. The most frequently signs and symptoms observed for the two diseases were the presence of joint noise, temporomandibular joint pain, pain on palpation in the masseter and trapezius muscles. In conclusion, due to the significant association between prevalence of CSD and TMD becomes important clinical research of neck structures during the physical examination for the diagnosis ofTMD.

Optimization of the ultrasound-assisted synthesis of allyl 1-naphthyl ether using response surface methodology

Allyl 1-naphthyl ethers are useful compounds for different purposes, but reported methods to synthesize them require long reaction times. In this work, we have obtained allyl 1-naphthyl ether in good yield using ultrasonic-assisted methodology in a 1-h reaction. A central composite design was used to obtain a statistical model and a response surface (p < 0.05; R2 = 0.970; R2adj = 0.949; R2 pred = 0.818) that can predict the optimal conditions to maximize the yield, validated experimentally.

Optimization of the ultrasound-assisted synthesis of allyl 1-naphthyl ether using response surface methodology.

Allyl 1-naphthyl ethers are useful compounds for different purposes, but reported methods to synthesize them require long reaction times. In this work, we have obtained allyl 1-naphthyl ether in good yield using ultrasonic-assisted methodology in a 1-h reaction. A central composite design was used to obtain a statistical model and a response surface (p<0.05; R(2)=0.970; R(2)(adj)=0.949; R(2)(pred)=0.818) that can predict the optimal conditions to maximize the yield, validated experimentally.