ABSTRACT
Baicalein (BA) is a flavonoid with wide-ranging pharmacological activity. However, its biological evaluation is hampered by its low solubility in aqueous medium, making forms of incorporation that improve its solubility necessary. In the present study, BA was combined with a solution of silk fibroin protein (SF), a biomaterial used too as a drug carrier, to evaluate the anti-inflammatory potential of this combination, in vivo, in an experimental model, zebrafish (Danio rerio). Baicalein-silk fibroin (BASF) improved the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical scavenging rate (95%) in comparison with BA in solution. The acute toxicity study and histopathological analysis in zebrafish showed that BASF has low cytotoxic potential, except for the maxim dose of 2000 mg/kg. The use of BA in combination with SF enhanced the anti-inflammatory effect of flavonoids by inducing inflammatory peritoneal edema through carrageenan and achieved 77.6% inhibition of abdominal edema at a dose of 75 mg/kg. The results showed that the BASF, significantly increases the bioavailability and therapeutic effect of flavonoids and several results observed in this study may help in the development of new drugs.
Subject(s)
Fibroins , Animals , Fibroins/pharmacology , Zebrafish , Flavonoids , Anti-Inflammatory Agents/pharmacology , Edema/chemically induced , Edema/drug therapy , SilkABSTRACT
Despite the many existing crosslinking procedures, glutaraldehyde (GA) is still the method of choice used in the manufacture of bioprosthesis. The major problems with GA are: (a) uncontrolled reactivity due to the chemical complexity or GA solutions; (b) toxicity due to the release of GA from polymeric crosslinks; and (c) tissue impermeabilization due to polymeric and heterogeneous crosslinks formation, partially responsible for the undesirable calcification of the bioprosthesis. A new method of crosslinking glutaraldehyde acetals has been developed with GA in acid ethanolic solution, and after the distribution inside de matrix, GA is released to crosslinking. Concentrations of hydrochloride acid in ethanolic solutions between 0.1 and 0.001 mol/L with GA concentration between 0.1 and 1.0% were measured in an ultraviolet spectrophotometer to verify the presence of free aldehyde groups and polymeric compounds of GA. After these measurements, the solutions were used to crosslink bovine pericardium. The spectrophotometric results showed that GA was better protected in acetal forms for acid ethanolic solution with HCl at 0.003 mol/L and GA 1.0%(v/v). The shrinkage temperature results of bovine pericardium crosslinked with acetal solutions showed values near 85 degrees C after the exposure to triethylamine vapors.
Subject(s)
Acetals/pharmacology , Collagen/chemistry , Collagen/drug effects , Glutaral/pharmacology , Polymers/chemical synthesis , Acetals/chemical synthesis , Acetals/chemistry , Animals , Cattle , Cross-Linking Reagents/chemistry , Cross-Linking Reagents/pharmacology , Differential Thermal Analysis , Elasticity , Ethanol/pharmacology , Glutaral/chemistry , Hydrogen-Ion Concentration , Models, Biological , Pericardium/chemistry , Pericardium/drug effects , Pericardium/metabolism , Polymers/chemistry , Spectrophotometry, Ultraviolet , Temperature , Tissue Engineering/methods , Wettability/drug effectsABSTRACT
Este trabalho estudou o comportamento de soluções de glutaraldeído utilizadas na fixação de biopróteses, por meio das relações 280/235 nm. Os resultados mostraram que este índice de controle analítico não é adequado, porque grandes variações nesta relação são devidas aos elevados valores de coeficientes de extinção molares das formas poliméricas. Foram detectadas também variações significativas nas absorbâncias em 280nm, sugerindo a ocorrência de alterações químicas do glutaraldeído em função do tempo (< 7 dias). Estes resultados mostram que estas soluções de glutaraldeído podem estar longe do ideal a obtenção de biopróteses homogêneas.
Abstract - This work studied the behavior of aqueous or buffered glutaraldehyde solutions used for the fixation of cardiac bioprostheses by means of the 280/235 nm ratios. The results showed that this analytical index may not be adequate since great variations are mainly due to the high extinction coefficients for the polymeric forms. Besides, variations were also observed in the 280 nm absorbancies, suggesting that significative changes may also occur in glutaraldehyde effective concentration (7 days). These results suggests that this type of glutaraldehyde solutions may be far from ideal for the manufacture of homogeneou
