Efeitos do flavonóide quercetina e dos corantes bixina e norbixina sobre parâmetros sanguíneos de coelhos Effects of the flavonoid quercetin and the natural dyes bixin and norbixin on blood parameters of rabbits

Avaliou-se a ação terapêutica da quercetina, bixina e norbixina, na dose diária de 0,01mol/kg, em coelhos hiperlipidêmicos induzidos por colesterol a 0,5% e ácido cólico a 0,1%, durante o período de vinte e oito dias, após o qual foram dosados colesterol, colesterol-HDL, triacilgliceróis, uréia, creatinina, ácido úrico, proteínas totais, cálcio, aspartato aminotransferase e alanina aminotransferase. Estes estudos são importante para se verificarem os efeitos de flavonóides e corantes sobre o metabolismo destas substâncias, permitindo a interpretação de desordens hepáticas ou renais. Os resultados mostraram que os teores de colesterol foram menores para os animais tratados com bixina (-4,03%) e quercetina (-35,07%), enquanto sua associação reduziu o nível de uréia em 5,73%. Nenhuma das substâncias testadas apresentou efeitos deletérios, todavia, não é possível demonstrar a inocuidade destes compostos.<br>The objective of this study was to evaluate the therapeutic action of quercetin, bixin and norbixin, in the daily dose of 0,01mol/kg, in hyperlipidemic rabbits induced by cholesterol at 0.5% and colic acid at 0.1%, during the period of twenty-eight days, after which they were anesthetized and samples of blood were collected, in order to determine cholesterol, HDL-cholesterol, triacylglycerols, urea, creatinine, uric acid, total proteins, calcium, aspartate aminotransferase and alanine aminotransferase. These researchs are important to verify the effects of flavonoids and natural dyes on the metabolism of these constituents, in order to study hepatic or renal disorders. The results showed that cholesterol was reduced by bixin (-44.03%) and by quercetin (-35.07%), while the association reduced urea in 5.73%. None of the constituents analyzed in this study presented deleterious effects and it was not possible to demonstrate the innocuity of these compounds

Is a change in juvenile hormone sensitivity involved in range expansion in an invasive beetle?

Introduction: It has been suggested that rapid range expansion could proceed through evolution in the endocrinological machinery controlling life-history switches. Based on this we tested whether the Colorado potato beetle, Leptinotarsa decemlineata, which has rapidly expanded its range across latitudinal regions in Europe, and shows photoperiodic adaptation in overwintering initiation, has different sensitivities to juvenile hormone (JH) manipulation along a latitudinal gradient. Results: A factorial experiment where beetles were reared either under a long or short day photoperiod was performed. Hormone levels were manipulated by topical applications. An allatostatin mimic, H17, was used to decrease and a juvenile hormone III analogue, pyriproxyfen, was used to increase the hormone levels. The effects of photoperiod and hormone manipulations on fecundity and overwintering related burrowing were monitored. Application of H17 decreased fecundity but did not induce overwintering related burrowing. Manipulation with pyriproxyfen increased fecundity and delayed burrowing. While small population-dependent differences in responsiveness to the topical application treatments were observed in fecundity, none were seen in overwintering related burrowing. Conclusions: The results indicate that the rapid photoperiodic adaptation manifested in several life-history and physiological traits in L. decemlineata in Europe is unlikely a result of population dependent differences in JH III sensitivity. While other endocrine factors cannot be ruled out, more likely mechanisms could be genetic changes in upstream elements, such as the photoperiodic clock or the insulin signaling pathway.peerReviewe