Concomitant and controlled release of furazolidone and bismuth(III) incorporated in a cross-linked sodium alginate-carboxymethyl cellulose hydrogel.

The combination of bismuth(III) citrate and the antibiotic furazolidone (FDZ) results in a synergetic effect on Helicobacter pylori eradication. However, the problems associated with their oral administration are challenges to overcome. Thus, in the present study, sodium alginate (SA)/carboxymethyl cellulose (CMC) blend hydrogels (SC) were developed for concomitant and controlled release of furazolidone and bismuth(III). The blank formulation (SCblank) and the three drug-loaded hydrogels (SCFDZ, SCBi, and SCFDZ-Bi) were prepared by casting method and characterized by infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, and X ray powder diffraction analyses. The swelling equilibrium and cumulative release amounts of FDZ and Bi3+ have indicated distinct behaviors of the hydrogels to different pH values. The bismuth-containing sample (SCFDZ-Bi) presents more resistance to degradation on a neutral solution and shows more suitable properties for controlled drug release than the sample without bismuth (SCFDZ). Microbiological studies, using Escherichia coli as a model, show bacteria viability reduction in presence of the drug-loaded samples. The developed system containing furazolidone and bismuth(III) appears to be promising for oral administration with concomitant and controlled release of these drugs aimed at the pharmacological treatment of gastrointestinal disorders.

Nematicidal potential of essential oils of Ageratum fastigiatum, Callistemon viminalis and Schinus terebinthifolius / Potencial nematicida de óleos essenciais de Ageratum fastigiatum, Callistemon viminalis e Schinus terebinthifolius

Some essential oils are rich in nematicidal compounds and can be used for the management of plant-parasitic nematodes. Laboratory and field studies aiming to evaluate the efficiency of this compounds are necessary. The objective of this research was to assess the nematicidal potential of essential oils from leaves of Ageratum fastigiatum and Callistemon viminalis, and green and mature fruits of Schinus terebinthifolius on the root-knot nematode Meloidogyne javanica. In laboratory, the essential oil of S. terebinthifolius green fruits reduced hatching by more than 80% and increased juvenile mortality by 300% when compared to Tween 20 + water. In the field, none of the essential oils controlled M. javanica in lettuce. In conclusion, the essential oil of S. terebinthifolius green fruits reduces the egg hatching and kills J2 of M. javanica in laboratory. In an infested field with an average of 555 J2/100 cm3 of soil, the application of the essential oils of S. terebinthifolius, C. viminalis and A. fastigiatum does not control M. javanica in lettuce.

Alguns óleos essenciais são ricos em compostos nematicidas e poderiam ser usados no manejo de fitonematoides. Estudos laboratoriais e de campo que visam avaliar a eficiência desses compostos são necessários. O objetivo desta pesquisa foi avaliar o potencial nematicida de óleos essenciais de folhas de Ageratum fastigiatum e Callistemon viminalis e frutos verdes e maduros de Schinus terebinthifolius sobre o nematoide de galhas Meloidogyne javanica. Em laboratório, o óleo essencial de frutos verdes de S. terebinthifolius reduziu mais de 80% a eclosão e aumentou em 300% a mortalidade de juvenis em comparação com Tween 20 + água. No campo, nenhum óleo essencial controlou M. javanica em alface. Em conclusão, o óleo de frutos verdes de S. terebinthifolius reduz a eclosão e mata J2 de M. javanica em laboratório. Em campo com infestação média de 555 J2/100 cm3 de solo, a aplicação dos óleos essenciais de S. terebinthifolius, C. viminalis e A. fastigiatum não controla M. javanica em alface.

Synthesis and phytotoxic activity of new pyridones derived from 4-hydroxy-6-methylpyridin-2(1H)-one.

Commercial dehydroacetic acid was converted into 4-hydroxy-6-methylpyridin-2(1H)-one (3), which was then condensed with several aliphatic aldehydes to produce seven new title compounds in variable yields (35-92%). Reaction of 3 with alpha,beta-unsaturated aldehydes resulted in the formation of condensed pyran derivatives 4g' and 4h'. A mechanism is proposed to explain the formation of such compounds. The effects of all methylpyridin-2(1H)-one derivatives on the development of the dicotyledonous species Ipomoea grandifolia and Cucumis sativus and the monocotyledonous species Sorghum bicolor were evaluated. At the dose of 6.7 x 10(-8) mol a.i./g substrate the compounds showed some phytotoxic selectivity, being more active against the dicotyledonous species. These compounds can be used as lead structures for the development of more active phytotoxic products.