Quantificação da cumarina no xarope de cumarí utilizando cromatografia líquida de alta eficiência.

Este trabalho tem como objetivo quantificar a cumarina no xarope de cumarú

Volatile organic compounds from filamentous fungi: a chemotaxonomic tool of the Botryosphaeriaceae family.

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PERFIL DOS COMPONENTES VOLÁTEIS PRODUZIDOS PELO FUNGO FITOPATÓGENO Albonectria rigidiuscula EM DIFERENTES CONDIÇÕES DE CULTIVO

The VOCs produced by the Albonectria rigidiuscula fungus in different conditions were obtained by headspace-solid phase microextraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). Fourty-four VOCs were identified in different culture media and incubation periods. The highest production of VOCs occurred in solid rice medium and 14 days of incubation. The compounds 3-methylbutan-1-ol, 2-methylbutan-1-ol, γ-muurolene and nerolidol acetate were produced by A. rigidiuscula in all culture conditions. γ-Muurolene was identified as the major compound (40.78%, 26.24% and 27.04%) in PD medium and it was suggested as a chemical marker for this fungus. The use of multivariate data analysis (PCA) and (HCA) allowed the discrimination of the volatile chemical profiles according to the culture medium

Vibrational spectroscopy of the seselin crystal

Seselin, C14H12O3, is a coumarin which crystallizes in a monoclinic structure P2(1)/b(C-2h(5)) with four molecules per unit cell. In a Fourier-transform Raman spectroscopic study performed at room temperature, several normal modes were observed. Vibrational wavenumber and wave vector calculations using density functional theory were compared with experiment, which allowed the assignment of a number of normal modes of the crystal. Temperature-dependent Raman spectra were recorded between 10 and 300 K. No anomalies were observed in the phonon spectra, indicating that the monoclinic structure remains stable. Copyright (c) 2007 John Wiley & Sons, Ltd

Withaferin A and Withanolide D Analogues with Dual Heat-Shock-Inducing and Cytotoxic Activities: Semisynthesis and Biological Evaluation

Withanolides constitute a valuable class of bioactive natural products because some members of the class are known to exhibit cytotoxic activity and also induce a cytoprotective heat-shock response. In order to understand the relationship between their structures and these dual bioactivities of the withanolide scaffold, we obtained 25 analogues of withaferin A (WA) and withanolide D (WD) including 17 new compounds by semisynthesis involving chemical and microbial transformations. Hitherto unknown 16β-hydroxy analogues of WA and WD were prepared by their reaction with triphenylphosphine/iodine, providing unexpected 5β-hydroxy-6α-iodo analogues (iodohydrins) followed by microbial biotransformation with <i>Cunninghamella echinulata</i> and base-catalyzed cyclization of the resulting 16β-hydroxy iodohydrins. Evaluation of these 25 withanolide analogues for their cytotoxicity and heat-shock-inducing activity (HSA) confirmed the known structure–activity relationships for WA-type withanolides and revealed that WD analogues were less active in both assays compared to their corresponding WA analogues. The 5β,6β-epoxide moiety of withanolides contributed to their cytotoxicity but not HSA. Introduction of a 16β-OAc group to 4,27-di-<i>O</i>-acetyl-WA enhanced cytotoxicity and decreased HSA, whereas introduction of the same group to 4-<i>O</i>-acetyl-WD decreased both activities

A Critical Review on Chagas Disease Chemotherapy

In this "Critical Review" we made a historical introduction of drugs assayed against Chagas disease beginning in 1912 with the works of Mayer and Rocha Lima up to the experimental use of nitrofurazone. In the beginning of the 70s, nifurtimox and benznidazole were introduced for clinical treatment, but results showed a great variability and there is still a controversy about their use for chronic cases. After the introduction of these nitroheterocycles only a few compounds were assayed in chagasic patients. The great advances in vector control in the South Cone countries, and the demonstration of parasite in chronic patients indicated the urgency to discuss the etiologic treatment during this phase, reinforcing the need to find drugs with more efficacy and less toxicity. We also review potential targets in the parasite and present a survey about new classes of synthetic and natural compounds studied after 1992/1993, with which we intend to give to the reader a general view about experimental studies in the area of the chemotherapy of Chagas disease, complementing the previous papers of Brener (1979) and De Castro (1993)