Natural Phenolic Compounds with Antithrombotic and Antiplatelet Effects: A Drug-likeness Approach.

BACKGROUND: Thrombosis is one of the major causes of morbidity and mortality in a wide range of vessel diseases. Several studies have been conducted to identify antithrombotic agents from medicinal plants, and phenolic compounds (PCs) have been shown to effectively inhibit plasma coagulation and platelet aggregation. OBJECTIVES: This study aimed to conduct a survey of the natural PCs with proven antithrombotic and antiplatelet activities, as well as to evaluate by computational modeling the physicochemical and toxicological properties of these compounds using drug-likeness approaches. METHODS: The data were collected from the scientific database: 'Web of Science', 'Scifinder', 'Pubmed', 'ScienceDirect' and 'Google Scholar', the different classes of PCs with antithrombotic or antiplatelet effects were used as keywords. These molecules were also evaluated for their Drug-Likeness properties and toxicity to verify their profile for being candidates for new antithrombotic drugs. RESULTS: In this review, it was possible to register 85 lignans, 73 flavonoids, 28 coumarins, 21 quinones, 23 phenolic acids, 8 xanthones and 8 simple phenols. Activity records for tannins were not found in the researched databases. Of these 246 compounds, 213 did not violate any of Lipinski's rules of five, of which 125 (59%) showed non-toxicity, being promising candidates for new potential antithrombotic drugs. CONCLUSION: This review arouses interest in the isolation of phenolic compounds that may allow a new approach for the prevention of both arterial and venous thrombosis, with the potential to become alternatives in the prevention and treatment of cardiovascular diseases.

Avaliação da citotoxicidade in vitro e genotoxicidade ex-vivo em compostos da Pavonia glazioviana Gürke (Malvaceae / Evaluation of in vitro cytotoxicity and ex-vivo genotoxicity in compounds from Pavonia glazioviana Gürke(Malvaceae)

Introdução: as terapias alternativas que utilizam plantas medicinais e fitoterápicos são bastante comuns no Brasil. Dentre várias espécies vegetais brasileiras utilizadas em terapias destacam-se as espécies da família Malvaceae. Objetivos: o presente estudo teve como objetivo avaliar a citotoxicidade in vitro e a genotoxicidade ex-vivo em compostos da Pavonia glazioviana Gürke espécie brasileira pertencente à família Malvaceae. Metodologia: métodos in vitro foram utilizados para verificar o potencial citotóxico por meio de ensaios hemolíticos e anti-hemolíticos e da análise genotóxica ex-vivo. O Extrato Etanólico Bruto (EEB) e Fração Clorofórmico (FC) foram obtidos na amostra vegetal utilizada neste estudo. Resultados: os produtos EEB-Pg e FC-Pg apresentaram baixo efeito citotóxico apenas nas concentrações de 50 e 100 µg / mL. As amostras expostas às concentrações de 500 e 1000 µg / mL apresentaram índice hemolítico alto a moderado com lise superior a 60%. Foi descrito efeito anti-hemolítico moderado em todas as amostras tratadas com 500 e 1000 µg / mL, com hemólise < 60%. Além disso, os compostos mostraram baixo efeito genotóxico ex-vivo, com um índice geral de células normais superior a 84% em todas as concentrações. Conclusões: os resultados sugerem um baixo perfil tóxico dos compostos obtidos da espécie Pavonia glazioviana, indicando limites seguros para o uso desses produtos naturais.

Introduction: alternative therapies using medicinal plants and herbal medicines are quite common in Brazil. Among several Brazilian plant species used in therapies, the species of the Malvaceae family stand out. Objetctives: the present study aimed to evaluate the in vitro cytotoxicity and ex-vivo genotoxicity in compounds of the Brazilian Pavonia glazioviana Gürke belonging to the Malvaceae family. Methodology: in vitro methods were used to verify the cytotoxic potential through hemolytic and antihemolytic assays and the ex-vivo genotoxic analysis. The Crude Etanolic Extract (CEE) and Cloroformic Fraction (CF) was obtained in vegetal sample used on this study. Results: the CEE-Pg and CF-Pg products only showed a low cytotoxic effect at the concentrations of 50 and 100 µg/mL. The exposure to the concentrations of 500 and 1000 µg/mL showed a high to moderate hemolytic index with lysis higher than 60%. A moderate anti-hemolytic effect was described in all samples treated with 500 and 1000 µg/mL, with hemolysis <60%. In addition, the compounds showed low ex-vivo genotoxic effect with a general index of normal cells greater than 84% at all concentrations. Conclusion: the results suggest a low toxic profile of the compounds obtained from the Pavonia glazioviana Gürke species belonging to the Malvaceae family, indicating safe limits for the use of these natural products.

In silico, in vitro and ex-vivo Toxicological Profiling of 5,7,4'-Trihydroxyflavone-8-C-ß-Glucopyranoside - Vitexin

This study aimed to evaluate the in silico, in vitro, and ex-vivo toxicity of vitexin, the flavonoid 5,7,4'- trihydroxyflavone-8-C-ß-glucopyranoside from Waltheria viscosissima. The chemical structure and predicted bioactive properties were also in silico analyzed. The in vitro and ex-vivo assays were performed according to the Ethics Code of the World Medical Association and were approved by the Ethics Committee of University Center of Patos (protocol number: 3.621.284). In silico analysis suggested that the molecule presents good oral bioavailability and good absorption; penetrating biological membranes. The toxicity tests revealed the potential effectiveness of the molecule in cellular protection against free radicals, in addition to possible antimutagenic, anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and apoptosis agonist activity. Hemolytic and genotoxic assessment detected low hemolysis rates in human red blood cells and no cellular toxicity against oral mucosa cells. The data suggest that vitexin is a safe molecule for possible therapeutic application and its toxicity profile indicates viability for future studies.

Ovicidal, pupicidal, adulticidal, and repellent activity of Helicteres velutina K. Schum against Aedes aegypti L. (Diptera: Culicidae).

Aedes aegypti is a vector of emerging and neglected diseases, such as dengue, chikungunya, and Zika. Helicteres velutina, known as "pitó" in Brazil, is traditionally used as an insect repellent, and several studies have demonstrated its larvicidal activity. The aim of this study was to investigate this species and evaluate its potential ovicidal, pupicidal, adulticidal, and repellent activity. The viability of the eggs was evaluated using different concentrations of the test substances for 25 days. The hexane fraction killed 72.7% of the eggs, while dichloromethane killed 67.7%. The survival of the pupae and adults was verified after 72 h and 48 h, respectively. The LC50 for the hexane and dichloromethane fractions was 0.12 mg/mL and 8.85 mg/mL for pupae, 8.01 mg/mL and 0.74 mg/mL for adults (tarsal test), and 0.05 mg/mL and 0.23 mg/mL for adults (body test), respectively. Repellency was assessed for 240 min using neonatal Wistar rats on a Y-tube olfactometer. The hexane fraction attracted mosquitoes to the test chamber, while the dichloromethane fraction had a repellent action. The 7,4'-di-O-methyl-8-O-sulfate flavone provides greater repellency, and this finding is similar to the results of the in silico studies that have shown the potential of this substance against adult mosquitoes. This suggests that 7,4'-di-O-methyl-8-O-sulfate flavone may be one of the substances present in the extract from aerial parts of H. velutina that is responsible for the repellent activity mentioned in traditional medicine. These findings provide a better understanding of the insecticidal and repellent activity of the extract, fraction, and compounds isolated from H. velutina against Ae. aegypti, thereby revealing its potential in the development of a more effective botanical insecticide.

Aedes aegypti é o vetor de doenças emergentes e negligenciadas, como dengue, chikungunya e Zika. Helicteres velutina, conhecida como 'pitó' no Brasil, é tradicionalmente usada como um repelente de insetos, estudos anteriores comprovaram sua atividade larvicida. O objetivo desta pesquisa foi investigar esta espécie, avaliando seu potencial ovicida, pupicida, adulticida e repelente. A viabilidade dos ovos foi avaliada utilizando diferentes concentrações das substâncias teste durante 25 dias, a fração hexano causou a inviabilização de 72,7% dos ovos, enquanto a diclorometano matou 67,7%. A sobrevivência de pupas e adultos foi verificada após 72 e 48 horas, respectivamente. A CL50 da fração hexano e diclorometano foi de 0,12 e 8,85 mg/mL para pupas; 8,0 e 0,74 mg/mL para adultos (teste tarsal); 0,05 e 0,23 mg/mL para adultos (teste corporal), respectivamente. A repelência foi avaliada durante 240 min utilizando neonatos de ratos Wistar em um olfatômetro de tubo Y. No teste de atração-repelência, a fração hexano atraiu mosquitos para camara teste, enquanto a fração diclorometano causou repelência. A 7,4'-di-O-metil-8-O-sulfato flavona proporcionol maior repelência, corroborando com estudos in silico que mostram potencial dessa substância em mosquitos adultos. Sugerindo que 7,4'-di-O-metil-8-O-sulfato flavona pode ser uma das substâncias presente no extrato das partes aéreas de H. velutina, responsável pela atividade repelente citada na medicina tradicional. Esses achados proporcionam uma melhor compreensão da atividade inseticida e repelente do extrato, fração e compostos isolados de H. velutina frente a Ae. aegypti mostrando potencial no desenvolvimento de um inseticida botânico mais eficaz.

Sidastrum paniculatum (L.) Fryxell (Malvaceae): A Promising Source of Bioactive Sulfated Flavonoids Against Aedes aegypti L.

Aedes aegypti L. is known as the most relevant vector mosquito for viruses such as yellow fever, chikungunya, dengue, and Zika, especially in places with unplanned urbanization, and erratic water supply. Plants used in folk medicine have become a useful source of active compounds with the potential to control the dissemination of Ae. aegypti. Compounds isolated from Malvaceae sensu lato have been previously reported as larvicides, repellents, and insecticides. Recent studies have demonstrated the anti Ae. aegypti activity of sulfated flavonoids, an uncommon type of flavonoid derivatives. This research reports the phytochemical investigation of Sidastrum paniculatum (L.) Fryxell, a Malvaceae species with the potential against Ae. aegypti. Chromatographic procedures resulted in the isolation of the compounds: stearic acid (1), N-trans-feruloyltyramine (2), acacetin (3), apigenin (4), tiliroside (5), along with the sulfated flavonoids: wissadulin (6), 7,4'-di-O-methyl-8-O-sulfate flavone (7), yannin (8), beltraonin (9a), 7-O-sulfate isoscutellarein (paniculatumin) (9b), and condadin (10). This is the first report of compound 7-O-sulfate isoscutellarein (9b). The structures were elucidated by spectroscopic analysis (NMR, LC-HRMS and FT-IR). The sulfated flavonoids identified were submitted to a ligand-based and structure-based virtual screening against two targets: 1YIY (from adult Ae. aegypti) and 1PZ4 (from Ae. aegypti larvae). The results indicated that when the O-sulfate group is bearing the position 7, the structures are potentially active in 1PZ4 protein. On the other hand, flavonoids with the O-sulfate group bearing position 8 were showed to be more likely to bind to the 1YIY protein. Our findings indicated that S. paniculatum is a promising source of sulfated flavonoids with potential against Ae. aegypti.

Insights on the Larvicidal Mechanism of Action of Fractions and Compounds from Aerial Parts of Helicteres velutina K. Schum against Aedes aegypti L.

Viral diseases transmitted by the female Aedes aegypti L. are considered a major public health problem. The aerial parts of Helicteres velutina K. Schum (Sterculiaceae) have demonstrated potential insecticidal and larvicidal activity against this vector. The objective of this research was to investigate the mechanisms of action involved in the larvicidal activity of this species. The cytotoxicity activity of H. velutina fractions and compounds of crude ethanolic extract of the aerial parts of this species was assessed by using fluorescence microscopy and propidium iodide staining. In addition, the production of nitric oxide (NO) and hemocyte recruitment were checked after different periods of exposure. The fluorescence microscopy revealed an increasing in larvae cell necrosis for the dichloromethane fraction, 7,4'-di-O-methyl-8-O-sulphate flavone and hexane fraction (15.4, 11.0, and 7.0%, respectively). The tiliroside did not show necrotic cells, which showed the same result as that seen in the negative control. The NO concentration in hemolymph after 24 h exposure was significantly greater for the dichloromethane fraction and the 7,4'-di-O-methyl-8-O-sulphate flavone (123.8 and 56.2 µM, respectively) when compared to the hexane fraction and tiliroside (10.8 and 8.3 µM, respectively). The presence of plasmocytes only in the dichloromethane fraction and 7,4'-di-O-methyl-8-O-sulphate flavone treatments suggest that these would be the hemocytes responsible for the highest NO production, acting as a defense agent. Our results showed that the larvicidal activity developed by H. velutina compounds is related to its hemocyte necrotizing activity and alteration in NO production.

Intestinal anti-inflammatory activity of xique-xique (Pilosocereus gounellei A. Weber ex K. Schum. Bly. Ex Rowl) juice on acetic acid-induced colitis in rats.

Inflammatory bowel disease (IBD) is characterized by severe mucosal damage in the intestine and a deregulated immune response. Natural products derived from plants that are rich in bioactive compounds are used by many patients with IBD. Xique-xique (Pilosocereus gounellei) is a cactus of the Caatinga family that has been used by the local population for food and medicinal purposes. The intestinal anti-inflammatory effect of xique-xique cladode juice was evaluated in the present study. A dose of 5 mL kg-1 had a protective effect on intestinal inflammation, with an improvement in macroscopic damage, and a decrease in pro-inflammatory markers and oxidative stress, in addition to preserving the colonic tissue. Immunohistochemical analysis revealed the downregulation of IL-17, NF-κB, and iNOS, and upregulation of SOCs-1, ZO-1, and MUC-2. These protective effects could be attributed to the phenolic compounds as well as the fibers present in xique-xique juice. Further studies are needed before suggesting the use of xique-xique juice as a new alternative for treating IBD.

New Sulphated Flavonoids and Larvicidal Activity of Helicteres velutina K. Schum (Sterculiaceae).

Helicteres velutina K. Schum (Sterculiaceae), commonly known in Brazil as 'pitó', is traditionally used by indigenous peoples as insecticides and repellents. The present work reports on the the phytoconstituents from aerial parts of H. velutina and evaluation of the larvicidal potential of its extract. The compounds were isolated using chromatographic techniques and identified by NMR, IR and LC-HRMS. This study led to the isolation of a fatty acid, one aliphatic alcohol, four chlorophyll derivatives, one steroid, triterpenes, a lignan, and flavonoids, highlighting the new compounds in the literature, 5,4'-di-hydroxy-7-methoxy-8-O-sulphate flavone (mariahine) (15a) and 5,3'-di-hydroxy-7,4'-dimethoxy-8-O-sulphate flavone (condadine) (15b). The work presented here contributes to the chemotaxonomic knowledge of the Sterculiaceae family by describing the occurrence of sulphated flavonoids in this family for the first time. The crude ethanolic extract of H. velutina featured robust larvicidal activity against Aedes aegypti larvae, showing that the extract can be useful as a domestic larvicide, just as indicated by traditional use, to combat A. aegypti, a vector insect of severe viral diseases, such as dengue and Zika.

Sulphated Flavonoids: Biosynthesis, Structures, and Biological Activities.

The great diversity of enzymatic reactions in plant secondary metabolism allows the continuous discovery of new natural compounds and derivatives. Flavonoids, for example, can be found as aglycone or as several sorts of glycosylated, acetylated, methylated, and sulphated derivatives. This review focuses on sulphated flavonoids, an uncommon group of flavonoid derivatives found in some plant families. This work presents a compilation of sulphated flavonoids and their natural sources reported in the literature. Biosynthetic aspects and biological activities have also been reviewed, showing that these particular kinds of natural compounds play an interesting role in plant metabolism, as well as being potential candidates for the development of new drugs.

Seasonal variability of phenolic compounds and antioxidant activity in prickly pear cladodes of Opuntia and Nopalea genres

Abstract The prickly pear is a cactaceae that have chemical compounds that act as natural antioxidants. In addition, the prickly pear is a plant widely used in semiarid region as it's considered very important forage for animal feed, especially in the dry season. The objectives of this research were to characterize the main classes of phytochemicals, determine the phenols content, flavonoids and anthocyanins and evaluate the antioxidant activity of the prickly pear cultivars Opuntia and Nopalea grown in the semiarid region of Pernambuco in two collection periods (dry and rainy). In the work crude ethanol extracts from cladodes of cultivars (IPA-20, Elephant Ear Mexican, F-08, V-19, Small palm, F-21 and IPA-Sertânia) were used. As for the class of phytochemical compounds from ethanol extract only the flavonoids and steroids were detected in all prickly pear cultivars, in both periods analyzed. The content of phenolic compounds ranges from 1.24 to 5.41 mg GAE g-1 DM, flavonoids 0.90 to 3.43 mg QE g-1 DM, anthocyanins from 0.05 to 0.34 µg QE 100 g-1 DM and antioxidant activity 39.59 to 217.17 µM TEAC g-1 DM. The occurrence of chemical variability and antioxidant activity were observed, both among the botanical cultivars studied and among the collection periods.

Phytochemical study of Pilosocereus pachycladus and antibiotic-resistance modifying activity of syringaldehyde

ABSTRACT Pilosocereus pachycladus F. Ritter, Cactaceae, popularly known as "facheiro", is used as food and traditional medicine in Brazilian caatinga ecoregion. The plant is used to treat prostate inflammation and urinary infection. The present work reports the first secondary metabolites isolated from P. pachycladus. Therefore, the isolated compound 4-hydroxy-3,5-dimethoxy benzaldehyde (syringaldehyde) was evaluated as modulator of Staphylococcus aureus pump efflux-mediated antibiotic resistance. The isolation of compounds was performed using chromatographic techniques and the structural elucidation was carried out by spectroscopic methods. In order to evaluate syringaldehyde ability to modulate S. aureus antibiotic resistance, its minimum inhibitory concentrations (µg/ml) was first determinate, then, the tested antibiotics minimum inhibitory concentrations were determined in the presence of the syringaldehyde in a sub-inhibitory concentration. The chromatographic procedures led to isolation of twelve compounds from P. pachycladus including fatty acids, steroids, chlorophyll derivatives, phenolics and a lignan. The syringaldehyde did not show any antibacterial activity at 256 µg/ml against S. aureus. On the other hand the compound was able to reduce the antibiotic concentration (tetracycline, norfloxacin, ethidium bromide) required to inhibit the growth of drug-resistant bacteria, showing the ability of syringaldehyde of inhibiting the efflux pump on these bacteria.

Alkaloids and Phenolic Compounds from Sida rhombifolia L. (Malvaceae) and Vasorelaxant Activity of Two Indoquinoline Alkaloids.

The follow-up of phytochemical and pharmacological studies of Sida rhombifolia L. (Malvaceae) aims to strengthen the chemosystematics and pharmacology of Sida genera and support the ethnopharmacological use of this species as hypotensive herb. The present work reports phytoconstituents isolated and identified from aerial parts of S. rhombifolia by using chromatographic and spectroscopic methods. The study led to the isolation of scopoletin (1), scoporone (2), ethoxy-ferulate (3), kaempferol (4), kaempferol-3-O-ß-d-glycosyl-6''-α-d-rhamnose (5), quindolinone (6), 11-methoxy-quindoline (7), quindoline (8), and the cryptolepine salt (9). The alkaloids quindolinone (6) and cryptolepine salt (9) showed vasorelaxant activity in rodent isolated mesenteric arteries.

New Alcamide and Anti-oxidant Activity of Pilosocereus gounellei A. Weber ex K. Schum. Bly. ex Rowl. (Cactaceae).

The Cactaceae family is composed by 124 genera and about 1438 species. Pilosocereus gounellei, popularly known in Brazil as xique-xique, is used in folk medicine to treat prostate inflammation, gastrointestinal and urinary diseases. The pioneering phytochemical study of P. gounellei was performed using column chromatography and HPLC, resulting in the isolation of 10 substances: pinostrobin (1), ß-sitosterol (2), a mixture of sitosterol 3-O-ß-d-glucopyranoside/stigmasterol 3-O-ß-d-glucopyranoside (3a/3b), 13²-hydroxyphaeophytin a (4), phaeophytin a (5), a mixture of ß-sitosterol and stigmasterol (6a/6b), kaempferol (7), quercetin (8), 7'-ethoxy-trans-feruloyltyramine (mariannein, 9) and trans-feruloyl tyramine (10). Compound 9 is reported for the first time in the literature. The structural characterization of the compounds was performed by analyses of 1-D and 2-D NMR data. In addition, a phenolic and flavonol total content assay was carried out, and the anti-oxidant potential of P. gounellei was demonstrated.

Phytoconstituents from Sidastrum micranthum (A. St.-Hil.) Fryxell (Malvaceae) and antimicrobial activity of pheophytin a

abstract Sidastrum micranthum (A. St.-Hil.) Fryxell, a member of the Malvaceae family, is called malva preta in Brazil. As this species is commonly used to treat bronchitis, cough, and asthma, better knowledge of its chemical compounds is important. The phytochemical study of its hexane extract, using chromatographic techniques, led to isolation of six compounds: the triterpene isoarborinol, a mixture of sitosterol and stigmasterol, sitosterol-3-O-β-D-glucopyranoside, pheophytin a, and 132-hydroxy-(132-S)-pheophytin a. Structural identification of these compounds was carried out using spectroscopic methods such as IR and 1D and 2D NMR (HOMOCOSY, HMQC, HMBC, and NOESY). Compounds isolated from S. micranthum were screened for their in vitro antifungal and antibacterial activity against twenty fungal and bacterial standard strains. Pheophytin a exhibited antimicrobial action against all microorganisms tested.

resumo Sidastrum micranthum (A. St.-Hil.) Fryxell, pertencente à família Malvaceae, é conhecida no Brasil como "malva preta". A espécie é popularmente usada contra bronquite, tosse e asma, mostrando a relevância de conhecer melhor sua composição química. O estudo fitoquímico do extrato hexânico da espécie, utilizando técnicas cromatográficas, conduziu ao isolamento de seis compostos: o triterpeno isoarborinol, mistura de sitosterol e estigmasterol, sitosterol-3-O-β-D-glicopiranosídeo, feofitina a e de 132-hidroxi-(132-S)-feofitina a. A identificação estrutural destes compostos foi realizada com base em métodos espectroscópicos, tais como IV, RMN 1D e 2D (HOMOCOSY, HMQC, HMBC e NOESY). As substâncias isoladas de Sidastrum micranthum foram avaliadas quanto às suas atividades antimicrobianas in vitro, contra vinte cepas fúngicas e bacterianas. A feofitina a mostrou ação antimicrobiana contra todos os microrganismos testados.

New Sulphated Flavonoids from Wissadula periplocifolia (L.) C. Presl (Malvaceae).

Wissadula periplocifolia (L.) C. Presl (Malvaceae) is commonly used in Brazil to treat bee stings and as an antiseptic. The antioxidant properties of its extracts have been previously demonstrated, thus justifying a phytochemical investigation for its bioactive phenolic constituents. This has yielded five new sulphated flavonoids: 8-O-sulphate isoscutellarein (yannin) (1a); 4'-O-methyl-7-O-sulphate isoscutellarein (beltraonin) (1b); 7-O-sulphate acacetin (wissadulin) (2a); 4'-O-methyl-8-O-sulphate isoscutellarein (caicoine) (2b) and 3'-O-methyl-8-O-sulphate hypolaetin (pedroin) (3b) along with the known flavonoids 7,4'-di-O-methyl-8-O-sulphate isoscutellarein (4), acacetin, apigenin, isoscutellarein, 4'-O-methyl isoscutellarein, 7,4'-di-O-methylisoscutellarein, astragalin and tiliroside. The compounds were isolated by column chromatography and identified by NMR (¹H, (13)C, HMQC, HMBC and COSY) and LC-HRMS. A cell based assay was carried out to evaluate the preliminary cytotoxic properties of the flavonoids against UVW glioma and PC-3M prostate cancer cells as well as non-tumour cell lines. The obtained results showed that acacetin, tiliroside, a mixture of acacetin + apigenin and the sulphated flavonoids 2a + 2b exhibited inhibitory activity against at least one of the cell lines tested. Among the tested flavonoids acacetin and tiliroside showed lower IC50 values, presenting promising antitumor effects.

Nanostructured layer-by-layer films containing phaeophytin-b: electrochemical characterization for sensing purposes.

This paper reports the study and characterization of a new platform for practical applications, where the use of phaeophytin-b (phaeo-b), a compound derived from chlorophyll, was characterized and investigated for sensing purposes. Modified electrodes with nanostructured phaeo-b films were fabricated via the layer-by-layer (LbL) technique, where phaeo-b was assembled with cashew gum, a polysaccharide, or with poly(allylamine) hydrochloride (PAH). The multilayer formation was investigated with UV-Vis spectroscopy by monitoring the absorption band associated to phaeo-b at approximately 410 nm, where distinct molecular interactions between the materials were verified. The morphology of the films was analyzed by atomic force microscopy (AFM). The electrochemical properties through redox behavior of phaeo-b were studied with cyclic voltammetry. The produced films were applied as sensors for hydrogen peroxide (H2O2) detection. In terms of sensing, the cashew/phaeo-b film exhibited the most promising result, with a fast response and broad linear range upon the addition of H2O2. This approach provides a simple and inexpensive method for development of a nonenzymatic electrochemical sensor for H2O2.

Biological activity of Herissantia crispa (L) Brizicky / Atividade biológica da Herissantia crispa (L) Brizicky

O extrato metanólico bruto (EMeOH) das partes aéreas da Herissantia crispa (L.) Brizicky, planta rica em flavonóides e que não possui estudos farmacológicos, foi testada para avaliar sua atividade sob os parâmetros comportamentais e determinar a dose letal 50 (DL50) em camundongos; atividade antimicrobiana e antiulcerogênica. O EMeOH (5000 mg/kg, v.o. ou 2000 mg/kg i.p.) não alterou os parâmetros comportamentais e não causou mortes nos animais. A amostra vegetal em estudo inibiu o crescimento bacteriano. O EMeOH (750 mg/kg) apresentou atividade anti-diarréica. O EMeOH (250, 500 e 750 mg/kg) foi capaz de inibir as lesões gástricas induzidas pelo 0,3 M HCl/etanol 60 por cento em camundongos. Desta forma, pode-se concluir que a planta em estudo apresenta atividade antiulcerogênica, entretanto, se faz necessário avaliar tal atividade através de modelos mais específicos e estudar o mecanismo de ação pelo qual a amostra vegetal protege a mucosa gástrica.

The crude methanol extract (EMeOH) of the aerial parts of Herissantia crispa (L.) Brizicky, plant riches in flavonoids and without pharmacological studies, was tested to value its activity under the behaviour parameters and to determine the lethal dose (LD50) in mice; antimicrobial and antiulcerogenic activities. The EMeOH (5,000 mg/kg, v.o. or 2,000 mg/kg i.p.) did not alter the behaviour parameters and there were not mice deaths. The extract inhibited the bacterial growth. The EMeOH (750 mg/kg) showed anti-diarroeal activity. The EMeOH (250, 500 and 750 mg/kg) decreased the gastric lesions induced by 0.3 M HCl/ethanol 60 percent in mice. In conclusion, the EMeOH presents anti-ulcerogenic activity;, however it is necessary to value the antiulcerogenic activity in more specific models and to study the action mechanism by which the vegetable sample protects the gastric mucosa.

Teor de bixina em quatro variedades de Bixa orellana L. cultivadas na Paraíba / Bixin content in four varieties of Bixa orellana L. grown in Paraíba

Neste trabalho foi verificado o teor de Óleos, sólidos e bixina em sementes de quatro variedades de Bixa orellana L. cultivadas na Paraíba: "Casca verde", "Casca vermelha", Bico de calango" e "Grão preto". Os melhores resultados foram obti­dos com os tipos "Casca verde" e "Casca vermelha" que apresentaram um rendimento em bixina pura, cristalina, de 1,3 e 1,1 por cento, respectivamente.

In this work it was verified the content of oils, solids and bixin in seeds of four varieties of Bixa orellana L. cultivated in Paraíba: "Casca verde", "Casca vermelha", Bico de calango" and "Grão preto". The best results were obtained with the types "Casca verde" and "Casca vermelha" that presented an yield in pure, crystalline bixina, of 1,3 and 1,1 percent, respectively.