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Soitinnus: sekakuoro. (SATB)

Antifungal derivatives from Piper mollicomum and P. lhotzkyanum (Piperaceae)

Bioguided fractionation of the extracts from leaves of Piper mollicomum and Piper lhotzkyanum against the fungi Cladosporium cladosporioides and C. sphaerospermum afforded seven bioactive compounds, four being chromenes: methyl 2,2-dimethyl-2H-chromene-6-carboxylate, methyl 8-hydroxy-2,2-dimethyl-2H-chromene-6-carboxylate, 2-methyl-2-[4'-methyl-3'-pentenyl]-2H-1-benzopyran-6-carboxylic acid, 2,2-dimethyl-2H-chromene-6-carboxylic acid, one a dihydrochalcone: 2',6'-dihydroxy-4'-methoxydihydrochalcone, and two flavanones: 7-methoxy-5,4'-dihydroxy-flavanone and 7,4'-dimethoxy-5-hydroxy-flavanone. The structures of the bioactive isolated derivatives were elucidated by interpretation of their NMR data [¹H and 13C (BBD, DEPT 135º)], and mass spectral data as well as by comparison with data described in the literature.

Calculation of radio electrical coverage in Medium-Wave Frequencies

The aim of this project is to accomplish an application software based on Matlab to calculate the radioelectrical coverage by surface wave of broadcast radiostations in the band of Medium Wave (WM) all around the world. Also, given the location of a transmitting and a receiving station, the software should be able to calculate the electric field that the receiver should receive at that specific site. In case of several transmitters, the program should search for the existence of Inter-Symbol Interference, and calculate the field strenght accordingly. The application should ask for the configuration parameters of the transmitter radiostation within a Graphical User Interface (GUI), and bring back the resulting coverage above a map of the area under study. For the development of this project, it has been used several conductivity databases of different countries, and a high-resolution elevation database (GLOBE). Also, to calculate the field strenght due to groundwave propagation, it has been used ITU GRWAVE program, which must be integrated into a Matlab interface to be used by the application developed.

Determinação de aflatoxina B1 em pimenta (Piper nigrum L.) e orégano (Origanum vulgare L.) por cromatografia em camada delgada e densitometria

An analytical study based on extraction with methanol-water, immunoaffinity cleanup and separation, identification and quantification of aflatoxin B1 by thin-layer chromatography,in ground black and white pepper and oregano was carried out. Validation of the applied methodology was done through accuracy and precision studies. Recoveries of aflatoxin B1 and relative standard deviations, from spice samples spiked at levels from 4.86 to 97.70 µg/kg, were, respectively, higher than 72% and lower than 20%. Application to spice samples available in Minas Gerais state, purchased at popular markets, showed no contamination with aflatoxin B1.

Composição e atividade antibacteriana dos óleos essenciais de Senecio crassiflorus var. crassiflorus

The essential oils of leaves, aerial and underground stems of Senecio crassiflorus var. crassiflorus were extracted by hydrodistillation and their analyses were performed by GC/MS. Qualitative and quantitative differences have been found between the analyzed parts. The main compounds of the essentials oils of the leaves were found to be oxygenated sesquiterpenes, while the oils from the aerial and underground stems showed sesquiterpene hydrocarbons as major constituents. Furthermore, the essential oils were tested against Staphylocccus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus. The essential oil of the leaves was shown to be the most active.

Flavonas, lignanas e terpeno de Piper umbellata (Piperaceae)

The phytochemical investigation of Piper umbellata leaves yielded nine compounds including one terpenoid glucoside, five flavones (vitexin 2"-O-β-glucopyranoside, apigenin 8-C-β-D-glucopyranoside,orientin 8-C-β-D-glucopyranoside,5-hydroxy-7,3',4'-trimethoxy-flavone and velutin), two lignans (sesamin e dihydrocubebin) and 4-nerolidylcathecol. Excepting 4-nerolidylcathecol, all compounds have not been described from this species yet.

Reaction mixtures formed by nitrite and selected sulfa-drugs showed mutagenicity in acidic medium

Nitrite, which is present in preserved meat and can be produced in the oral cavity by reduction of nitrate taken from vegetables, could react in stomach with nitrosatable drugs, giving genotoxic-carcinogenic N-nitroso compounds (NOC). The mutagenicity of reaction mixtures formed by sodium nitrite and selected sulfa-drugs (sulfathiazole, HST; phtalylsulfathiazole, PhST; complex Co(II)-sulfathiazole, Co(II)-ST) in acidic medium was evaluated using the Salmonella typhimurium reverse mutation assay (Ames test), with TA98 and TA 100 strains. The reactions were carried out at room temperature, with a mole ratio [nitrite]/[sulfa-drug] > 1. The three reaction mixtures showed mutagenic effects in the considered range.

Caldensinic acid, a benzoic acid derivative and others compounds from Piper carniconnectivum

A benzoic acid derivative - caldensinic acid; E-phytyl hexadecanoate; β-sitosterol and stigmasterol mixture and phaeophytin a were isolated from the aerial parts of Piper carniconnectivum. The structures of these compounds were established unambiguously by IR, MS, 1D and 2D NMR analysis.

Constituintes químicos das folhas de Senna spectabilis (DC) Irwin & Barneby var. excelsa (Schrad.) Irwin & Barneby

From leaves of Senna spectabilis var. excelsa were isolated caffeine, the triterpenes lupeol, α-amyrin, β-amyrin, cycloeucalenol, friedelin and ursolic, oleanolic and betulinic acids, besides the steroids sitosterol and stigmasterol and their respective glucosides. The structures of these compounds were established by spectroscopic analysis including two-dimensional NMR methods and comparison with published spectral data. This paper deals with the first report of these compounds in S. spectabilis var. excelsa.

Recovery of manganese and zinc from spent Zn-C and alkaline batteries in acidic medium

The anode and the internal paste of spent Zn-C and alkaline batteries were leached with 2 mol L-1 H2SO4 at 80 ºC for 2 h. Solid/liquid ratio was 1/10 (g mL-1). The leachate was treated with Na2S in order to precipitate Hg, Cd and Pb. Zn was quantitatively isolated at pH 1,5-2 by adding Na2S. Mn can be precipitated at pH close to 7. Na2S may be replaced by oxalic acid. Zn precipitated at pH around 0, whereas Mn was quantitatively recovered at pH > 4. Acidity control is a critical parameter. Na2SO4 and carbon are the end products.

Citocalasinas produzidas por Xylaria sp., um fungo endofítico de Piper aduncum (piperaceae)

A chemical study on the EtOAc extract produced by Xylaria sp., an endophytic fungus from Piper aduncum, resulted in the isolation of a new cytochalasin 1, along with five known 19,20-epoxycytochalasin D (2), C (3), N (4), Q (5), and R (6). The 1-6 were evaluated against the fungi C. cladosporioides and C. sphaerospermum and only 5 showed weak activity. The cytotoxicity in vitro against HeLA and CHO cells lines were investigated and the cytochalasins 2-4, and 6 showed a strong activity against HeLA. The DNAdamaging activity of 1-6 were also investigated against mutant strains of S. cerevisiae.

Interaction between cationic and conventional nonionic surfactants in the mixed micelle and monolayer formed in aqueous medium

Mixed micellization and surface properties of cationic and nonionic surfactants dimethyl decyl-, tetradecyl- and hexadecyl phosphineoxide mixtures are studied using conductivity and surface tension measurements. The models of Rubingh, Rosen, and Clint, are used to obtain the interaction parameter, minimum area per molecule, mixed micelle composition, free energies of mixing and activity coefficients. The micellar mole fractions were always higher than ideal values indicating high contributions of cationics in mixed micelles. Activity coefficients were less than unity indicating synergism in micelles. The negative free energies of mixing showed the stability of the surfactants in the mixed micelles.

Sensitive method for determination of piplartine, an alkaloid amide from Piper species, in rat plasma samples by liquid chromatography-tandem mass spectrometry

Piplartine (PPTN) is an alkaloid amide found in Piper species that presents different activities. PPTN determination in rat plasma is necessary to better understand its biological effects. The aim of this study was to develop a sensitive LC-MS/MS method for the determination of PPTN in rat plasma. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, and stability have been assessed and were within the recommended guidelines. The validated method proved to be suitable in a pilot study of PPTN kinetic disposition in rat plasma after a single intraperitoneal dose, and represents an appropriate tool to further pharmacokinetic studies.

Composição química e avaliação da atividade antimicrobiana do óleo essencial das folhas de Piper malacophyllum (C. Presl.) C. DC.

This work reports the chemical composition as well as the antibacterial, antifungal and antiparasitic activities of the leaf essential oil from Piper malacophyllum. The oil was extracted by hydrodistillation and analyzed by GC-FID, GC-MS and polarimetry. Among the 28 compounds identified, (+)-camphor was the major constituent. The essential oil showed activity against most of the microorganisms tested, especially antifungal action, with a MIC of 500 µg mL-1 against Trichophyton mentagrophytes and Cryptococcus neoformans. This is the first study reporting the composition and biological properties of leaf essential oil from P. malacophyllum.