Aqueous solutions of four cationic poly(propylenimine) low-generation dendrimers of different architecture and hydrophobicity have been examined as media for acid-base reactions of indicator dyes. The cationic dendrimers in solution can be considered as oligomers of cationic polyelectrolytes, or surfactant-like species, able to form micelles through self-association or sometimes even as unimolecular micelles. The dendrimers influence the ionization constants, tautomeric equilibria, and absorption/emission/excitation spectra of indicator dyes. The p K a values of the majority of the indicator dyes decrease in dendrimer solutions, often by 1-2 p K a units, similar to effects registered in micellar solutions of cationic surfactants. Analogously, the shifts of absorption band maxima indicate that the microenvironments of the dyes bound to the dendrimers are less polar than in water. However, some spectral effects denote the specificity of the dendrimers. The greatest difference between the dendrimers and spherical surfactant micelles is revealed by kinetic processes, especially of bromophenol blue alkaline fading in a dendrimer solution but not in a micellar surfactant solution. Within the dendrimer series, the most significant differences were observed for substances possessing n-dodecyl tails on the one hand and those without such hydrophobic portions on the other. For the last-named, the decrease in p K a's of indicators, band shifts of their anions, and in particular displacement of tautomeric equilibria compared with aqueous solutions are much smaller than for more hydrophobic dendrimers.

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Purification of extracts from Prangos haussknechtii Bioss afforded prenylated coumarins 1 and 2, monoterpenoid 3, amino acid derivative 4, and seven known compounds. Spectroscopic methods permitted establishment of the structures and relative configuration of these compounds. The pure isolates were tested for antioxidant and anti-inflammatory activities using lipid peroxidation (LPO), 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and cyclooxygenase (COX-1 and -2) enzyme inhibitory assays. Compounds 1-4 inhibited LPO with IC values between 43 and 114 μM and reduced MTT to formazan blue between 48 and 128 μM. In anti-inflammatory assays using cyclooxygenase enzymes, COX-1 and -2, these compounds showed inhibition, with IC values ranging from 34 to 56 μM.