Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto

About: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto is a based out in . It is known for research contribution in the topics: Population & Catalysis. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

The Change in the Properties of Sodium Dodecyl Sulfate Micelles upon Addition of Isomeric and Unsaturated Short-Chain Alcohols Probed by Photophysical Methods.

Abstract: The properties of sodium dodecyl sulfate micelles (SDS) in the presence of 1-propanol, 2-propanol, and 2-propen-1-ol (allyl alcohol) were investigated using electrical conductivity and fluorescence quenching methods. The constants of association of the alcohols to SDS micelles, obtained experimentally and calculated from linear solvation energy relationship analysis, are in the range 1–2 M −1 , indicating that these additives behave not only as cosolvents but also as micellar surface active solutes. Larger molecular volume and lower basicity of the alcohol favor partitioning to the micelle. The formation of smaller micelles upon addition of the alcohols is accompanied by an enhancement of solute intermicellar migration and intramicellar quenching rate constants. In particular, the micelle fragmentation–coagulation process of the SDS (0.04 M)/allyl alcohol (1.5 M) system occurs in the time range of 1.5 μs, as indicated by the intermicellar exchange rate constant of the N -dodecylpyridinium ion.

Trypanocidal activity of pimarane diterpenes from Viguiera arenaria (Asteraceae).

Abstract: Five structurally related pimarane diterpenes isolated from the roots of Viguiera arenaria and a further compound obtained by chemical derivatization were evaluated in vitro against the trypomastigote forms of Trypanosoma cruzi. The natural compound ent-15-pimarene-8β,19-diol and the derivative ent-8(14),15-pimaradiene-3β-acetoxy showed the highest trypanocidal activity, displaying IC50 values of 116.5 ± 1.21 and 149.3 ± 1.07 µM, respectively, while the positive control, violet gentian, showed an IC50 of 76 µM. Based on the results, it can be concluded that minor structural differences among the tested diterpenes influence significantly the trypanocidal activity, thus bringing new perspectives to the establishment of structure-activity relationships among this type of metabolites to the treatment of Chagas' disease. Copyright © 2008 John Wiley & Sons, Ltd.