Descoberta de novos fármacos anti-tumorais e anti-bacterianos de extratos vegetais brasileiros através de screening em larga escala

Plants have played a significant role in the treatment of cancer and infectious diseases for the last four decades. The discovery and introduction to market of paclitaxel, the vinca alkaloids, etoposide, and many antibacterial drugs support drug discovery programs based on natural products. Natural products have been rediscovered as important tools for drug development despite advances in combinatorial chemistry, due to the complex molecular structures able to interact with mammalian cell targets. The Brazilian flora, the most diverse in the world, has become an interesting spot to prospect for new chemical leads or hits due to its species diversity and associated chemical richness. Screening programs have been established in Brazil as a strategy to identify potentially active substances. High throughput screening techniques allow for the analysis of large numbers of extracts in a relatively short period of time, and can be considered one of the most efficient ways of finding new leads from natural products. An updated review of the current status of the biological screening program is presented and recent results from new antitumoral and antibacterial chemical leads are discussed.Plantas são uma importante fonte de novos protótipos há pelo menos quatro décadas. A descoberta e introdução no mercado de paclitaxel, dos alcalóides da vinca, etoposídeo e muitos agentes antibacterianos têm servido de apoio ao desenvolvimento de programas de descobrimento de novos fármacos baseados em produtos naturais. Produtos naturais foram recentemente redescobertos como importante ferramenta na descoberta de novos fármacos devido às estruturas moleculares complexas capazes de interagir com alvos em células de mamíferos. A flora brasileira, a mais rica do mundo, tornou-se um importante sítio para prospecção de novos protótipos em decorrência da riqueza de espécies vegetais relacionada a uma possível diversidade química. Programas de triagem têm sido introduzidos no Brasil contrapondo a devastação de florestas relacionadas a atividades rurais, extrativismo madeireiro e mineral. Ensaios em larga escala permitem a análise de um grande número de amostras em um tempo relativamente pequeno, e pode ser considerado como o método mais eficaz para a descoberta de novos fármacos a partir de plantas. Dados atualizados relativos a programas de triagem que objetivam a identificação de novos protótipos antitumorais e antibacterianos são comentados

Determinação da atividade citotóxica a artemia de extratos de Annonaceae

A família das Annonaceae pertence à classe Magnoliopsida, subclasse Magnoliidae e ordem Magnoliales. Estima-se que existam entre 2.000 e 2.300 espécies1,2, sendo a maior de sua Ordem1. As espécies de Annonaceae são encontradas nos trópicos e são especialmente características de florestas sempre verdes de planícies em grande parte dos trópicos do velho mundo2. No Brasil, encontram-se amplamente distribuídas

Can mouth washes containing chlorhexidine 0.12% be used as synonym of a water solution of chlorhexidine 0.12%?

;Gluconato de clorexidina (CHX) é um fármaco considerado padrão ouro, em Odontologia, amplamente usado como referência em estudos ;in vitro; e ;in vivo;. Em razão da facilidade de acesso, enxaguatórios bucais que contêm CHX 0,12% são usados em substituição à solução aquosa de clorexidina (CHX 0,12%), em experimentos laboratoriais. É sabido que devido à palatabilidade do produto, os mesmos enxaguatórios bucais contêm compostos voláteis em sua formulação, além da CHX 0.12%. Visto que voláteis adicionados podem acrescentar poder antibacteriano à formulação, a comparação da resposta antibacteriana da solução aquosa de CHX em diferentes concentrações e de Periogard;®; é proposta no presente artigo. Para tanto, utilizou-se o ensaio do disco de difusão em ágar com inóculos de ;Streptococcus mutans;, ;Streptococcus sanguinis; e ;Escherichia coli;. Periogard;®; mostrou atividade antibacteriana significativa contra as três cepas analisadas, quando comparada à atividade de CHX 0.12% (p;0,05). A presença de compostos voláteis no Periogard;®; foi analisada por GC-MS e observou-se que mentol, mentona, isomentol, acetato de mentila, trans-anetol e eugenol estão presentes na formulação. Deste modo, o uso de Periogard;(r); como sinônimo de CHX 0,12% deve ser evitado, uma vez que sua atividade se assemelha àquela da CHX diluída a 1%.;;Chlorhexidine digluconate (CHX) is a gold standard drug in dentistry and is widely used as a reference in both ;in vitro; and ;in vivo;experiments. Due to ease of access, mouth washes containing CHX 0.12% are used as a substitute for aqueous CHX 0.12% solution in laboratory experiments. Additionally, it is well known that for product flavor purposes, volatile compounds are added to mouth washes formulations. Volatiles added to CHX 0.12% may improve wash's antibacterial ability. Volatiles add potency to the mouth wash formulation. Compared with an aqueous CHX 0.12% solution, it is proposed that CHX solutions and Periogard;®; would have antimicrobial activity. Antimicrobial activity was assessed in the present study via disk diffusion assays against ;Streptococcus mutans;, ;Streptococcus sanguinis;and ;Escherichia coli;. Periogard;®; showed a significantly higher antibacterial activity in relation to CHX 0.12% (p;0.05). Periogard;(r); volatiles were analyzed by gas-chromatography/mass spectrometry (GCMS) and the presence of antibacterial menthol, menthone, isomenthol, menthyl acetate, trans-anethol and eugenol was verified. Finally, the use of Periogard;®; as a synonym of CHX 0.12% must be avoided, because its antibacterial activity is closely related to CHX 1%.

Neem Azadirachta indica A. Juss. (Meliaceae) toxicity in Artemia sp: comparison of a commercial preparation and the pure oil

Introdução - Azadirachta indica A. Juss. (Meliaceae) é conhecida popularmente por Neem (nim) ou margosa e é caracterizada por ser uma frondosa árvore, presente em regiões tropicais sendo, provavelmente, originada da Ásia. É empregada há tempos não só em medicina e cosmética como também na agricultura, sendo empregada como praguicida. A azdirachtina é a substância ativa presente no óleo responsável por seu efeito praguicida. O presente trabalho comparou os efeitos tóxicos de uma formulação comercial e do óleo puro de Azadirachta indica A. Juss. em Artemia sp. Material e Métodos - Foram utilizadas artêmias no estágio náuplio I ou II as quais foram submetidas a diferentes concentrações do óleo puro e do produto formulado, tendo sido computada a presença de morte após 24 e 48 horas da exposição. Resultados - A formulação comercial empregada apresentou-se significativamente (p < 0.05) mais tóxica do que o óleo puro da planta. Conclusão - Desde que o produto formulado é aquele empregado na agricultura, existe um risco maior se comparado ao óleo puro, quando atinge animais que habitem um corpo de águaIntroduction - Azadirachta indicates A. Juss. (Meliaceae), is popularity knows as Neem or margosa. It is characterized by a leaf tree, present in tropical areas, probably originated from Asia. It is popularly used not only in medicine and cosmetic, but also in the agriculture, as a pesticide. The azadirachtin is the active substance of the oil and is the responsible for its pesticide effect. The current study compared the toxic effects of a commercial formulation made with the Neem oil and the pure Neem oil against Artemia sp. Material and Methods - The artemias employed here were in the nauplii I or II stage. These animals were submitted to different concentrations of the pure oil of the formulated product. Death was assessed at 24 and 48 hours after the exposure. Results - Results showed that the commercial formulation was significantly (p < 0.05) more toxic when compared to the pure oil. Conclusion - Since the formulated product is employed as agricultural pesticide, it would be represent a great risk when animals from aquatic environment were attained than the pure oil of the plan

The influence of Brazilian plant extracts on Streptococcus mutans biofilm

Nineteen plant extracts obtained from plants from the Brazilian Amazon showed activity against planktonic Streptococcus mutans, an important bacterium involved in the first steps of biofilm formation and the subsequent initiation of several oral diseases. Objective: Our goal was to verify whether plant extracts that showed activity against planktonic S. mutans could prevent the organization of or even disrupt a single-species biofilm made by the same bacteria. Material and Methods: Plant extracts were tested on a single-bacteria biofilm prepared using the Zürich method. Each plant extract was tested at a concentration 5 times higher than its minimum inhibitory concentration (MIC). Discs of hydroxyapatite were submersed overnight in brain-heart infusion broth enriched with saccharose 5%, which provided sufficient time for biofilm formation. The discs were then submersed in extract solutions for one minute, three times per day, for two subsequent days. The discs were then washed with saline three times, at ten seconds each, after each treatment. Supports were allowed to remain in the enriched medium for one additional night. At the end of the process, the bacteria were removed from the discs by vortexing and were counted. Results: Only two of 19 plant extracts showed activity in the present assay: EB1779, obtained from Dioscorea altissima, and EB1673, obtained from Annona hypoglauca. Although the antibacterial activity of the plant extracts was first observed against planktonic S. mutans, influence over biofilm formation was not necessarily observed in the biofilm model. The present results motivate us to find new natural products to be used in dentistry

Extracts from Amazonian plants have inhibitory activity against tyrosinase: an in vitro evaluation

Dermatological disorders related to pigmentation result in tenuous hyper or hypopigmentation Cosmetic and pharmaceutical products containing depigmenting substances are used in the treatment of patients who have high pigmentation disorders, such as melasma or chloasma, post-inflammatory hyperpigmentation, senile lentigo and ephelides. Skin lightening agents are not yet totally effective or safe and therefore intensive research for the discovery of new agents is continuous. Enzyme inhibitors involved in melanogenesis, such as tyrosinase, have been discovered in Asian countries, including those isolated from plant extracts. The Brazilian flora has the highest species diversity in the world, and the chemical, pharmacological and cosmetic potential for the discovery of new skin whitening agents is in proportion with this biodiversity. For these reasons, 25 aqueous and 24 organic extracts obtained from 19 plants native to the Amazon rain forest and to the Atlantic forest, belonging to 11 different families, were evaluated as tyrosinase inhibitors. Nine out of 49 extracts showed inhibitory activity in the screening process. The 50% inhibitory activity (IA50) was calculated, revealing that the most active extracts were the organic extracts from the leaves and stem of Ruprechtia sp. (IA50 33.76 mg.mL-1) and the organic extract from the aerial organs of Rapanea parviflora (IA50 64.19 mg.mL-1).Problemas dermatológicos relacionados com a pigmentação resultam em hiperpigmentações ou hipopigmentação cutâneas. Produtos cosméticos e farmacêuticos com atividade despigmentante são utilizados para o tratamento de pacientes que apresentam distúrbios de hiperpigmentação, tais como melasma ou cloasma, hiperpigmentação pós-inflamatória, lentigem senil e efélides. Os despigmentantes atualmente utilizados não são totalmente eficazes ou seguros, razão pela qual há intensa pesquisa, principalmente em países asiáticos, com a finalidade de se obter novos agentes com esta ação, em especial inibidores de enzimas envolvidas na melanogênese, como a tirosinase. Considerando-se que algumas substâncias obtidas de plantas apresentam essa atividade, a flora brasileira constitui-se uma fonte potencial de obtenção de novos despigmentantes. Por essa razão, 25 extratos aquosos e 24 orgânicos obtidos de 19 plantas da Floresta Amazônica e Mata Atlântica, provenientes de 11 diferentes famílias, foram avaliados quanto à atividade de inibição da tirosinase. Do total de 49 extratos testados, 9 mostraram atividade. Os valores de concentração da atividade inibitória 50% (AI 50%), foram calculados e o mais ativo foi o extrato orgânico das folhas e caule de Ruprechtia sp. (AI50 33,76 mg.mL-1) seguido do extrato orgânico dos órgãos aéreos de Rapanea parviflora (AI50 64,19 mg.mL-1)

Antibacterial activity of Apocynaceae extracts and MIC of Tabernaemontana angulata stem organic extract

Thirty-eight aqueous and organic extracts obtained from 11 Amazonian Apocynaceae species were submitted to an antimicrobial dilution in broth media screening for Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, performed on microtiter plates. The organic extract obtained from the stem of Tabernaemontana angulata presented activity against Gram positive Staphylococcus aureus. The minimal inhibitory concentration of the organic crude extract was 2.50-1.25 mg/mL. Cloramphenicol was used as standard. Alkaloids and triterpenes were found in the active organic extract.Trinta e oito extratos orgânicos e aquosos obtidos de 11 espécies de Apocynaceae foram submetidos a triagem utilizando o método da microdiluição em caldo contra Staphylococcus aureus, Pseudomonas aeruginosa e Candida albicans. O extrato orgânico obtido do caule de Tabernaemontana angulata apresentou atividade contra a bactéria Gram positiva S. aureus. A concentração inibitória mínima verificada para esse extrato variou de 2,50 a 1,25 mg/mL. Cloranfenicol foi utilizado como antimicrobiano padrão. A análise fitoquímica indicou a presença de triterpenos e alcalóides no extrato ativo

Effects of exposure to glyphosate in male and female mice behavior in pubertal period

The present study aims to investigate the effects of pre-pubertal exposure of male and female mice to a commercial formulation of glyphosate on sexual dimorphism observed in animal models of emotionality, anxiety and depression. For this, mice were exposed from 23 days of age (PND) until PND 45 to glyphosate (50 mg/kg, per os) or saline solution, and, ten days after the end of treatments, male and female mice were observed in the open field (OF), elevated plus maze (EPM) or forced swimming test (FWT). Results showed that exposure to glyphosate: 1) reduced the locomotion frequency of male mice similarly to female mice in the OF and female mice had an increase in rearing behavior and in the immobility time; 2) reduced in male mice the motor activity both in the OF and EPM, while no effects were observed in female mice; 3) in the SWT male mice had a decreased time of float similarly female mice. We concluded that pre-pubertal exposure to glyphosate reduced in male mice the capacity of exploration in the OF and EPM tests suggesting that the herbicide interfered with the central mechanism related to brain masculinization of exploratory and anxiety behavioral models. In the FWT it was observed a decreased depressive response in male mice while in female an increased response was detected.O presente estudo teve como objetivo investigar em camundongos machos e fêmeas o efeito da exposição a uma formulação comercial de glifosato durante o período de pré-pubere em modelos comportamentais de emocionalidade, ansiedade e depressão. Para isto, camundongos foram expostos a partir de 23 dias de idade (dia pós-natal- PND) até o PND 45 ao glifosato (50 mg/kg, oral route) ou solução salina. Dez dias após o término do tratamento, os animais, machos e fêmeas, foram observados no campo aberto (OF), labirinto em cruz elevado (EPM) ou teste de natação forçada (FWT). Os resultados mostraram que a exposição ao glifosato: 1) reduziu de forma similar a frequência de locomoção dos camundongos em ambos os sexos; 2) reduziu a atividade motora tanto no OF como no PM em camundongos machos, sem alterações observadas em fêmeas; 3) no SWT os camundongos machos apresentaram redução no tempo de flutuação similar ao das fêmeas. Concluiu-se que a exposição pré-pubere ao glifosato reduziu em machos a capacidade de exploração no OF e EPM e no tempo de flutuação no FWT sugerindo que o herbicida interferiu com mecanismos centrais relacionados com masculinização do cérebro ligados a exploração e ansiedade. No FWT observou-se menor depressão em machos e exacerbação da resposta em fêmeas

Anti-Streptococcal activity of Brazilian Amazon Rain Forest plant extracts presents potential for preventive strategies against dental caries

Caries is a global public health problem, whose control requires the introduction of low-cost treatments, such as strong prevention strategies, minimally invasive techniques and chemical prevention agents. Nature plays an important role as a source of new antibacterial substances that can be used in the prevention of caries, and Brazil is the richest country in terms of biodiversity. Objective: In this study, the disk diffusion method (DDM) was used to screen over 2,000 Brazilian Amazon plant extracts against Streptococcus mutans. Material and Methods: Seventeen active plant extracts were identified and fractionated. Extracts and their fractions, obtained by liquid-liquid partition, were tested in the DDM assay and in the microdilution broth assay (MBA) to determine their minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs). The extracts were also subjected to antioxidant analysis by thin layer chromatography. Results: EB271, obtained from Casearia spruceana, showed significant activity against the bacterium in the DDM assay (20.67±0.52 mm), as did EB1129, obtained from Psychotria sp. (Rubiaceae) (15.04±2.29 mm). EB1493, obtained from Ipomoea alba, was the only extract to show strong activity against Streptococcus mutans (0.08 mg/m