Saponinas triterpênicas das raízes de guettarda pohliana müll. Arg. (Rubiaceae)

The phytochemical investigation of Guettarda pohliana roots led to the isolation of 28-O-beta-D-glycopyranosyl-3-O-beta-D-quinovopyranosyl quinovic acid, 28-O-beta-D-glycopyranosyl-3-O-beta-D-glycopyranosyl quinovic acid, 3-O-beta-D-glycopyranosyl quinovic acid, 28-O-beta-D-glycopyranosyl-3-O-beta-D-glycopyranosyl cincholic acid along with quinovic acid, daucosterol and 4,5-O-dicaffeoyl quinic acid. The structures of the isolated compounds were assigned on the basis of spectroscopic data, including two-dimensional NMR methods. The antiradical activity of the crude methanolic extract and of its fractions was evaluated.

Estudo fitoquímico das cascas das raízes de Zanthoxylum rigidum Humb. & Bonpl. ex Willd (Rutaceae)

Chemical investigation from root barks of Z. rigidum, resulted in the isolation of lupeol, a mixture of steroids campesterol, sitosterol, stigmasterol, sacarose, hesperidin, N-methylatanine and 6-acetonyldihydrochelerythrine. Their structures were established by spectral data analysis. No previous work has been reported on Z. rigidum species.

Toxicidade e atividade antioxidante de flavonoides das cascas das raízes de Lonchocarpus filipes

The phytochemical investigation of dichloromethane extract from root bark of Lonchocarpus filipes Benth (Leguminosae) afforded four flavonoids including three dibenzoylmethane derivatives rarely found in nature. The structures were established based on their spectral data (¹H and 13C NMR, 2D-NMR) as being: lanceolatin B (1), pongamol (2), (E)-7-O-methylpongamol (3) and (E)-9-O-methylpongamol (4). Compound (4) is described herein for the first time as a natural product. The extracts and the isolated compounds (1), (2) and (3) displayed high toxicity in the brine shrimp lethality assay. Only compound (2) showed antioxidant activity using a DPPH radical scavenging assay. This is the first report on the phytochemical study of Lonchocarpus filipes.

Estimativa da incerteza de medição em análise cromatográfica: abordagem sobre a quantificação de carbamato de etila em cachaça

The measurement uncertainty is useful to estimate the confidence of analytical results. Nowadays, a result without the uncertainty statement cannot be considered reliable, but the scientific literature still lacks examples of the estimate of the measurement uncertainty. This paper presents a practical and reliable description of the measurement uncertainty estimation of the analytical determination of ethyl carbamate in cachaça by GC-IDMS. The isotope dilution technique (ID) associated with GC-MS was used to improve the accuracy. The uncertainty estimated corresponds to 10% of the mass fraction of ethyl carbamate (115 ± 11) ng/g, which is in agreement with ppb level.

Constituintes químicos das folhas e avaliação da atividade anti-inflamatória de extratos das raízes e folhas de Guettarda pohliana Müll. Arg. (Rubiaceae)

This phytochemical investigation of Guettarda pohliana leaves led to the isolation of the triterpenes pomolic acid, rotundic acid, 3β,6α,19α,23-tetrahydroxyurs-12-en-28-oic acid, clethric acid, ursolic acid and oleanolic acid, the monoterpenoids loliolide and secoxyloganin, besides daucosterol and steroids. The structures of the isolated compounds were assigned on the basis of NMR data, including two-dimensional NMR methods. The anti-inflammatory activity of the crude methanolic extracts from leaves and roots, as well as of their fractions, was evaluated.

Influência da secagem sobre o rendimento e composição química dos compostos voláteis das raízes de Piper piscatorum Trel. & Yunck. (Piperaceae)

In this study, we evaluated the yield and chemical composition of volatile compounds obtained from fresh, dried at 30 and 40 ºC respectively of Piper piscatorum, employing the technique of hydrodistillation. The volatile were chemically characterized by GC-MS and GC-FID. The main volatile compounds were selin-11-en-4-a-ol (57,63 ± 3,07%; 53,95 ± 1,56% and 56,20 ± 0,43%) and benzyl benzoate (15,40 ± 0,36%; 16,32 ± 0,85% and 15,04 ± 0,24%).The drying of the raw material reduced yield of volatile compounds, changing their chemical compositions.

Estimativa da incerteza de medição: estudo de caso no ensaio de migração de ε-caprolactama com determinação por CG-DIC

The estimation of measurement uncertainty of an analytical result is an important tool to be applied for compliance to ISO IEC 17025. Through the available guides it is possible to establish procedures and criteria for the estimation of measurement uncertainty. This paper presents a case study on the estimation of measurement uncertainty in migration the test of ε-caprolactam from the polyamide 6 packages to fatty foods with determination by GC-FID. The calculation methodology used for the estimation of measurement uncertainty for the migration test was developed based on the guides EURACHEM / CITAC and ISO GUM, taking into account relevant aspects of the migration test. The expanded uncertainty estimated was approximately 23% of the concentration of migration.

Alcaloides das cascas das raízes de Zanthoxylum spp

In 1959, Gottlieb and Antonaccio published a study reporting the occurrence of lignan sesamin and triterpene lupeol in Zanthoxylum tingoassuiba. In this work we describe the phytochemical study of the root bark of the Z. tingoassuiba which allowed the identification of the lupeol, sesamin, and alkaloids dihydrochelerythrine, chelerythrine, anorttianamide, cis-N-methyl-canadine, predicentine, 2, 3-methylenedioxy-10,11-dimethoxy-tetrahydro protoberberine. The investigation of hexane and methanol extracts of the root bark of Z. rhoifolium and Z. stelligerum also investigated showed the presence of alkaloids dihydrochelerythrine, anorttianamide, cis-N-methyl-canadine, 7,9-dimethoxy-2,3-methylenedioxybenzophenanthridine and angoline. The occurrence of 2,3-methylenedioxy-10,11-dimethoxy-tetrahydro protoberberine is first described in Z. tingoassuiba and Z. stelligerum. This is also the first report of the presence of hesperidin and neohesperidin in roots of Z. stelligerum.

Pregnanos e outros constituintes das raízes de Macrosiphonia petraea (A. St.-Hil.) Kuntze (Apocynaceae)

Macrosiphonia petraea (A. St.-Hil.) Kuntze is a plant popularly known as "velame". Its root infusion is used in the folk medicine of Mato Grosso do Sul, Brazil, for the treatment of inflammatory diseases. Phytochemical investigation of the roots of this species led to the identification of 17 compounds belonging to four different classes: two pregnanes, 12β-hydroxypregna-4,6,16-triene-3,20-dione, neridienone A, and 12β-hydroxypregna-4,6-diene-3,20-dione, cybisterol, one hydroxylated fatty acid, 5-hydroxy-octadeca-6(E)-8(Z)dienoic acid, two lignoids, pinoresinol and 8a-hydroxypinoresinol, ten pentacyclic triterpenoids, and two steroids.

Constituintes químicos e avaliação das atividades antioxidante e anti-inflamatória das raízes de Sabicea brasiliensis wernh (Rubiaceae)

The phytochemical investigation of Sabicea brasiliensis roots led to the isolation of 5-O-caffeoylquinic acid, 3,5- and 4,5-O-dicaffeoylquinics acids, scopoletin, ursolic acid, a mixture of β-sitosterol, stigmasterol and campesterol, daucosterol and saccharose. The structures of the isolated compounds were assigned on the basis of one- and two-dimensional NMR spectroscopic methods and by comparison with literature data. The anti-inflammatory and antioxidant activities of the crude methanolic extract and its fractions were analyzed.

Medição e interpretação de valores do potencial redox (E H) em matrizes ambientais

Direct measurements of Redox Potential (ORP) have been used to infer the degree of electrons availability in waters, wastewaters, sediments and soils. Although the interpretation of the results obtained in direct measurements is not trivial, this parameter is part of a list of compulsory determinations required by many Environmental State Agencies as well as consulting companies. Nonetheless, the vast majority of E H reported values are not corrected to the reference electrode used, what makes most of the data incomparable with the literature, and not suitable for a correct environmental diagnostics.

COMPOSIÇÃO QUÍMICA DAS CASCAS DAS RAÍZES E FLORES DEPoincianella pyramidalis (Fabaceae)

Chemical investigation of the MeOH extract of root barks of P. pyramidallis (Tul.) L. P. Queiroz resulted in the isolation of 3,3'-dimethylellagic acid and 3,3'-dimethylellagic acid-4'-O-β-D-xyloside. Lupeol, β-sitosterol/stigmasterol and the mixture of fatty acid methyl ester derivatives were also obtained. Chromatographic procedures of the MeOH extract of the flowers of this species led to obtain an unusual mixture of fatty alcohols, β-sitosterol/stigmasterol, α-amyrin, β-amyrin and methyl gallate. The structures of the isolates were established by spectral data analysis. This is the first occurrence of 3,3'-dimethylellagic acid, 3,3'-dimethylellagic acid-4'- O-β-D-xyloside and free fatty alcohols in the Fabaceae family.

Colonização de raízes de plantas daninhas cultivadas in vitro e em vasos por Ralstonia solanacearum, biovares 1, 2 e 3

No presente trabalho, a colonização de raízes de espécies de plantas daninhas por estirpes das biovares 1, 2 e 3 de Ralstonia solanacearum foi avaliada in vitro e em casa de vegetação. Na condição in vitro, sementes foram submetidas à quebra de dormência, desinfestadas e semeadas em meio de cultura Murashige & Skoog (MS) modificado. A bactéria foi inoculada, colocando uma porção da massa no meio MS ao lado das plântulas. A colonização de raízes foi avaliada visualmente de acordo com a concentração de bactérias ao redor e na extensão das raízes e comparada a uma escala diagramática que variou de 1 a 4. Foi analisada a área abaixo da curva de colonização de raízes. Em casa de vegetação, populações de seis variantes das mesmas biovares foram quantificadas a partir de raízes de plantas daninhas. A bactéria foi inoculada nas raízes sem ferimentos, vertendo-se 100 ml da suspensão bacteriana na concentração de aproximadamente 10(8) ufc/ml por vaso. A avaliação foi feita aos 35 dias após a inoculação através do plaqueamento dos extratos diluídos das raízes e contagem posterior das colônias. Foram observados diferentes sintomas e níveis de colonização de raízes pela bactéria nas espécies de plantas estudadas. Os dois métodos permitiram o estudo da colonização de raízes com resultados análogos, sugerindo que ambos permitem obter resultados similares. Entretanto, a técnica in vitro é promissora como método auxiliar para a avaliação da colonização radicular de grande número de espécies botânicas por diferentes isolados de R. solanacearum.

Inibidor de tripsina em raízes de Eucalyptus urophylla

As raízes de eucalipto (Eucalyptus urophylla) podem estar associadas a fungos como Pisolithus tinctorius, formando uma simbiose conhecida como ectomicorriza, mas também podem estar colonizadas por fungos patogênicos, como Rhizoctonia solani, agente causal do tombamento de plantas em viveiros. O objetivo deste trabalho foi verificar a presença de atividade inibitória de tripsina, uma serino-protease, em raízes de E. urophylla e a atividade de tripsina em filtrados desses fungos. Alíquotas de extrato protéico bruto de raízes de E. urophylla e frações protéicas parcialmente purificadas por cromatografia de exclusão molecular, do tipo Sephacryl S-100-HR, foram testadas para atividade inibitória de tripsina. Proteínas do extrato ou das frações, quando incubadas com o substrato BAPNA (a-benzoil-arginina-p-nitroanilida) e tripsina comercial na presença de tampão Tris-HCl 0,1 M (pH 8,0), resultou em atividade de inibidor de tripsina ao redor de 80%. Filtrados de meios de cultura de P. tinctorius e R. solani foram parcialmente purificados em cromatografia de exclusão molecular, porém atividade de tripsina sobre o substrato BAPNA não foi verificada em nenhuma das frações. Portanto, não foi possível estabelecer uma correlação direta entre o inibidor da planta e proteases dos fungos. Os resultados apresentados abrem novas perspectivas para o estudo dessas proteínas nas interações entre patógenos e simbiontes para espécies de eucalipto.