Mesilato de desferroxamina como candidato a adjuvante farmacêutico e cosmético / Desferroxamine mesylate as a candidate for pharmaceutical and cosmetic adjuvant

Este trabalho propôs o uso do fármaco quelante mesilato de desferroxamina (DFO) como agente adjuvante para estabilização química e microbiológica de formulações. Soluções de ácido ascórbico (AA) 5,0% (p/v) foram preparadas com sistemas antioxidantes constituídos por diferentes combinações de DFO, ácido etilenodiamino tetra-acético (EDTA) e metabissulfito de sódio, cada adjuvante na concentração máxima de 0,1% (p/v). Os sistemas foram testados previamente quanto à atividade antioxidante, mediante adição de um complexo de ferro (III) redox-ativo e ensaio baseado em fluorescência. Os sistemas também foram associados ao metilparabeno e avaliados quanto à atividade antimicrobiana pelo método turbidimétrico, utilizando-se a técnica de microdiluição em meios líquidos e cepas padrão de bactérias e fungos, incluindo S. aureus (ATCC 6538), E. coli (ATCC 8739), P. aeruginosa (ATCC 9027), C. albicans (ATCC 10231) e A. brasiliensis (ATCC 16404). As soluções de AA foram expostas a condições de teste de estabilidade acelerada e avaliadas quanto à estabilidade química, empregando-se método volumétrico validado para quantificar AA. Verificou-se que o EDTA foi o agente quelante que melhor contribuiu na estabilidade química da solução de AA, entretanto, o DFO apresentou desempenho muito superior ao EDTA para bloquear a atividade pró-oxidante do ferro. Além disso, o DFO foi fator relevante na inibição do crescimento microbiano e demonstrou sinergia com o metilparabeno. A otimização estatística dos resultados indicou que o uso do DFO nos sistemas antioxidante e conservante pode reduzir consideravelmente a concentração dos adjuvantes convencionais, EDTA, metabissulfito e metilparabeno, os quais são muitas vezes associados a reações de hipersensibilidade ou a danos ao meio ambiente

In this work it was proposed the use of the chelating drug desferroxamine mesylate (DFO) as adjuvant for chemical and microbiological stabilization of formulations. Ascorbic acid (AA) solutions 5.0% (w/v) were prepared with antioxidant systems containing different combinations of DFO, ethylenediaminetetraacetic acid (EDTA) and sodium metabisulphite, using a maximum concentration of 0.1% (w/v) for each adjuvant. Previously, the systems were spiked with a redox-active iron (III) complex and tested for antioxidant activity by fluorescence-based assay. The systems also were associated with methylparaben and evaluated for antimicrobial activity by turbidimetric method, using the microdilution technique and standard strains of bacteria and fungi, including S. aureus (ATCC 6538), E. coli (ATCC 8739), P. aeruginosa (ATCC 9027), C. albicans (ATCC 10231) and A. brasiliensis (ATCC 16404). The AA solutions were exposed to accelerated stability test conditions and evaluated for chemical stability, using a volumetric method that was validated to quantify AA. It was found that EDTA was the chelating agent that most contributed to the chemical stability of AA solution, however, DFO demonstrated a much higher performance to EDTA to block the pro-oxidant activity of iron. In addition, DFO was a relevant factor in the inhibition of microbial growth and showed synergy with methylparaben. The statistical optimization of the results indicated that the use of DFO in the antioxidant and preservative systems might considerably reduce the concentration of the conventional adjuvants, EDTA, metabisulphite and methylparaben, which are often associated with hypersensitivity reactions or environmental damage

Biological functions of histidine-dipeptides and metabolic syndrome

The rapid increase in the prevalence of metabolic syndrome, which is associated with a state of elevated systemic oxidative stress and inflammation, is expected to cause future increases in the prevalence of diabetes and cardiovascular diseases. Oxidation of polyunsaturated fatty acids and sugars produces reactive carbonyl species, which, due to their electrophilic nature, react with the nucleophilic sites of certain amino acids. This leads to formation of protein adducts such as advanced glycoxidation/lipoxidation end products (AGEs/ALEs), resulting in cellular dysfunction. Therefore, an effective reactive carbonyl species and AGEs/ALEs sequestering agent may be able to prevent such cellular dysfunction. There is accumulating evidence that histidine containing dipeptides such as carnosine (beta-alanyl-L-histidine) and anserine (beta-alanyl-methyl-L-histidine) detoxify cytotoxic reactive carbonyls by forming unreactive adducts and are able to reverse glycated protein. In this review, 1) reaction mechanism of oxidative stress and certain chronic diseases, 2) interrelation between oxidative stress and inflammation, 3) effective reactive carbonyl species and AGEs/ALEs sequestering actions of histidine-dipeptides and their metabolism, 4) effects of carnosinase encoding gene on the effectiveness of histidine-dipeptides, and 5) protective effects of histidine-dipeptides against progression of metabolic syndrome are discussed. Overall, this review highlights the potential beneficial effects of histidine-dipeptides against metabolic syndrome. Randomized controlled human studies may provide essential information regarding whether histidine-dipeptides attenuate metabolic syndrome in humans.

Hypoxia Activates Toll-like Receptor 4 Signaling in Primary Mouse Hepatocytes Through the Receptor Clustering within Lipid Rafts

PURPOSE: Transient hypoxia is an initial event that accentuates ischemia/reperfusion (I/R) injury in the liver. Hepatic ischemia/reperfusion (I/R) injury is largely related to innate immunity via Toll-like receptor 4 (TLR4) signaling. However, the mechanism by which hypoxia could lead to activate TLR4 signaling remains unclear. Therefore, the aim of this experimental study investigates how TLR4 signalling is activated by hypoxia. METHODS: Hepatocytes were isolated from male wild-type (C57BL/6) mice (8~12 weeks old) by an in situ collagenase (Type IV, Sigma-Aldrich) perfusion technique. In this study, using primary mouse hepatocytes in culture to 1% oxygen, detection of TLR4 translocation to the lipid rafts on the cell membrane by immunofluorescence staining and immunoblotting was saught. RESULTS: Hypoxia caused TLR4/MD2 and beta2-Integrin (CD11b/CD18) translocation to lipid rafts associated with CD14 in hepatocytes. The cholesterol sequestering agent, Nystatin and Filipin prevented hypoxia-induced TLR4/MD2 translocation to lipid rafts. Consistent with a role for oxidative stress in this effect, in vitro H2O2 treatment of hepatocytes similarly caused TLR4/MD2 translocation to lipid rafts. In addition, translocation of hypoxia-induced TLR4 complex was inhibited by N-acetylcysteine (NAC) demonstrating that the activation of TLR4 signaling is dependent on ROS. Further, the cholesterol sequestering agent, nystatin, prevented hypoxia-induced high mobility group box 1 (HMGB1) release in hepatocytes. CONCLUSION: These results suggest that ROS dependent TLR4 signaling is achieved following receptor translocation to the lipid raft in hepatocytes. We hypothesized that this mechanism is required for the release of HMGB1, an early mediator of injury and inflammation in hepatic I/R injury.