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Commercially certified organic propolis produced in areas of environmental conservation and reforestation forests of Southern Brazil are generally poor in flavonoids, although one of its variants – Brazilian certified organic propolis 1 (OP1) – has shown strong antioxidant activity. The objective was to identify active compounds from OP1 related to its strong antioxidant activity. OP1 ethanolic extracts were subjected to liquid-liquid fractionation, and the fractions presenting the strongest antioxidant activity were combined and purified into subfractions. Compounds isolated from the most active subfractions had their structure elucidated by Nuclear Magnetic Resonance (NMR). As a result, five lignans and two lignan-precursors were isolated, and four of them are herein reported for the very first time in propolis. Hence, these compounds may be used as chemical markers for product standardization and authentication purposes, since OP1 is only produced by honeybees in native forests and its botanical origins remain unknown.

We evoke here events that took place in an ordinary school, the Teacher Training College in Coimbra (Portugal), during the on-going revolutionary process (processo revolucionario em curso; PREC), in an attempt to understand people’s actions within the collective becoming of a certain time and place, and to grasp how memory works as a narrative of the recollection of events connected with the course of the individual and the society. We equate the issue of memory – as the essential dimension, when collecting information, of the construction of individual and collective identity, embodied by the relevant social frameworks – with the feeling, relevance and interpretation of such memory at the time of its recovery. We listened to the memories revived during the interviews and to the narratives reconstructed, either through our intervention fostering the active search for memories, or actively listening and participating in their stories, focusing on their personal experiences as teachers or students of that i...

Gelatinization of the starch obtained from fruit seed such as mango and cumbaru was investigated applying an analytic methodology developed in the polymer nuclear magnetic resonance (NMR) laboratory at IMA/UFRJ, employing high resolution nuclear magnetic resonance spectroscopy in the solid state for hydrogen nucleus, using 1H HR-MAS pulse sequence. The results showed that NMR can be used instead of some techniques normally applied to study the gelatinization process, because 1H HR-MAS and relaxation time allow the evaluation of this process at the molecular level. NMR was also able to indicate the best gelatinization conditions. To start this study the glass transition (Tg) determination was a first step, because the Tg of seed starches are different than the Tg of starches derived from cereal, for example. The 1H HR-MAS NMR showed some useful information on the fruit seed starches gelatinization process. X-ray measurements were also used to support the data obtained from NMR technique. It was verified, f...

In this work a series of {[RuCl2(dppb)](μ-4,4′-N-N)}4 complexes were synthesized and characterized by elemental analysis, cyclic voltammetry and differential pulse voltammetry and UV–Vis and 31P{1H} NMR spectroscopies; [(μ-4,4′-N-N=pyrazine (pz), 4,4′-bipyridine=(4,4′-bipy), 1,2-bis-trans-(4-pyridyl)ethane = (pyeta) and 1,2-bis-trans-(4-pyridyl)ethylene=(pyetil) as bridging alterdentate ligands (alterdentate ligands are molecules (or ions), with two equivalent ligating atoms or ligating sites that do not simultaneously bind to a metallic center [Zelewsky von A. in Stereochemistry of Coordination Compounds, Inorganic Chemistry, A Textbook Series; John Wiley & Sons, Inc.: New York, 1995: p. 45] [1]) and 1,4-bis(diphenylphosphino)butane=dppb]. Electrochemical experiments (cyclic voltammetry and differential pulse voltammetry) suggest that for longer ligands the interaction between two ruthenium atoms is weak and for short ligands like pyrazine the corresponding interaction is strong. The analysis of the X-ra...

From woods of Picrasma crenata, a new stereoisomer dihydronorneoquassin was obtained together with others well knowns dihydronorneoquassin, parain, alpha-neoquassin, beta-neoquassin and quassin. The structures were determined by spectroscopic data and chemical evidence.

From the aerial parts of Cissus sicyoides , a new coumarin glycoside 5,6,7,8-tetrahydroxycoumarin-5 g -xylopyranoside was obtained together with known coumarin sabandin, two flavonoids kaempferol 3-rhamnoside and quercetin 3-rhamnoside and two steroids, sitosterol and 3 g - O - g - d -glucopyranosylsitosterol. The structure of compounds was elucidated by spectral analyses.

The methanol extract of the stem bark of Trichilia estipulata afforded four aryltetralin lignan glycosides which were identified on the basis of spectroscopic analysis of their acetates as (−)-isolariciresinol-3α-O-β-D-xylopyranoside and the new lignans (+)-4′-0-methyl-9′-deoxiisolariciresinol-3α-O-β-D-glucopyranoside, (−)-lyoniresinol-3α-L-rhamnopyranoside.