Untersuchung von Fetten und ?len.

Ohne Zusammenfassung     

Reduction of Weed Growth under the Influence of Extracts and Metabolites Isolated from Miconia spp.

Weeds pose a problem, infesting areas and imposing competition and harvesting difficulties in agricultural systems. Studies that provide the use of alternative methods for weed control, in order to minimize negative impacts on the environment, have intensified. Native flora represents a source of unexplored metabolites with multiple applications, such as bioherbicides. Therefore, we aimed to carry out a preliminary phytochemical analysis of crude extracts and fractions of Miconia auricoma and M. ligustroides and to evaluate these and the isolated metabolites phytotoxicity on the growth of the target species. The growth bioassays were conducted with Petri dishes with lettuce, morning glory, and sourgrass seeds incubated in germination chambers. Phytochemical analysis revealed the presence of flavonoids, isolated myricetin, and a mixture of quercetin and myricetin. The results showed that seedling growth was affected in a dose-dependent manner, with the root most affected and the seedlings of the lettuce, morning glory, and sourgrass as the most sensitive species, respectively. Chloroform fractions and myricetin were the most inhibitory bioassays evaluated. The seedlings showed structural changes, such as yellowing, nonexpanded cotyledons, and less branched roots. These results indicate the phytotoxic potential of Miconia allelochemicals, since there was the appearance of abnormal seedlings and growth reduction.     

Untersuchung von Schokolade, Marzipan, Zucker, Fruchtsaft, Marmelade, Gelee usw

Ohne Zusammenfassung     

1H NMR investigation of ring mobility of 1,5-benzodiazepine-2,4-diones

The ring mobility of some 1,5-benzodiazepine-2,4-diones and 1,4-benzodiazepin-2-one has been investigated by the temperature dependence of their ¹H NMR spectra. The activation parameters have been obtained, and the influence of N-1 substitution on the ring mobility is discussed, taking into account previously reported data for similar compounds.     

The variability of composition of the volatile fraction of olive oil

Aroma of olive oil is a very complex mixture of components. Analysis of head space of a series of virgin olive oil samples indicate a great variability of volatile substances composition in olives and these data probably should be related to the story of olives after collecting.