RESUMO
In this work, we developed an HPLC method to simultaneously quantify and hence evaluate the stability, distribution, and antioxidant capacity of six isoflavones: genistein, genistin, daidzein, daidzin, glycitin, and biochanin A. Isoflavones have been described as having an important estrogenic activity to treat menopausal symptoms and can reduce postmenopausal bone loss and also participate in the prevention of cardiovascular diseases. These beneficial properties are believed derived from their capacity to act as free-radical scavengers. Isoflavones are formulated in capsules and creams and also can be used as antioxidants in liposomes. HPLC separation was achieved on an Agilent Hypersil ODS C18 column. The mobile phase consisted of 0.02-0.2% orthophosphoric acid in water-acetonitrile with gradient elution. The diode array detector was operated at 260 nm. The hydrophobicity of isoflavones was determined through their distribution in octanol-buffer. These results allowed us to establish a relation between chemical structure, pKa, lipophilicity, and the characteristics of the dispersion medium. Photolysis of hydrogen peroxide was used to measure the HO⢠scavenging capability of isoflavones. In liposomes, the order of reactivity of the studied compounds was genistein > biochanin A > genistin > daidzein > daidzin > glycitin.
Assuntos
Antioxidantes/análise , Sequestradores de Radicais Livres/análise , Isoflavonas/análise , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão , Sequestradores de Radicais Livres/farmacologia , Peróxido de Hidrogênio/antagonistas & inibidores , Radical Hidroxila/química , Isoflavonas/farmacologia , Lipossomos/antagonistas & inibidores , Estrutura Molecular , Fotólise , Fatores de TempoRESUMO
Ursolic, oleanolic and betulinic acids are representative pentacyclic triterpenoids found in various plants and fruits. Despite having marked antitumor potentials, the very poor water solubility of these triterpenes hinders treatment development. Nanotechnology can enhance solubility, stability, bioavailability and phytochemical delivery, improving the therapeutic efficiency of triterpenes. This review focuses on the formulation, characterization and in vitro/in vivo evaluation of several delivery nanosystems used to enhance the physicochemical properties of ursolic, oleanolic and betulinic acids.
Assuntos
Antineoplásicos/administração & dosagem , Nanocápsulas/química , Neoplasias/tratamento farmacológico , Triterpenos Pentacíclicos/administração & dosagem , Animais , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Disponibilidade Biológica , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Humanos , Ácido Oleanólico/química , Triterpenos Pentacíclicos/química , Triterpenos Pentacíclicos/uso terapêutico , Solubilidade , Triterpenos/química , Lipossomas Unilamelares/química , Água , Ácido Betulínico , Ácido UrsólicoRESUMO
In this work, the relationship between the molecular structure of three flavonoids (kaempferol, quercetin and morin), their relative location in microheterogeneous media (liposomes and erythrocyte membranes) and their reactivity against singlet oxygen was studied. The changes observed in membrane fluidity induced by the presence of these flavonoids and the influence of their lipophilicity/hydrophilicity on the antioxidant activity in lipid membranes were evaluated by means of fluorescent probes such as Laurdan and diphenylhexatriene (DPH). The small differences observed for the value of generalized polarization of Laurdan (GP) curves in function of the concentration of flavonoids, indicate that these three compounds promote similar alterations in liposomes and erythrocyte membranes. In addition, these compounds do not produce changes in fluorescence anisotropy of DPH, discarding their location in deeper regions of the lipid bilayer. The determined chemical reactivity sequence is similar in all the studied media (kaempferol < quercetin < morin). Morin is approximately 10 times more reactive than quercetin and 20 to 30 times greater than kaempferol, depending on the medium.
Assuntos
Flavonoides/química , Sequestradores de Radicais Livres/química , Oxigênio Singlete/química , Flavonoides/farmacologia , Sequestradores de Radicais Livres/farmacologia , Lipossomos/químicaRESUMO
Retinoids are lipophilic compounds that are highly used in cosmetics/therapeutics for skin disorders. Conventional formulations are limited by poor water solubility, high chemical/photochemical instability and the irritation of retinoids. Interestingly, lipid nanoparticles enable the administration of retinoids in aqueous media, providing drug stabilization and controlled release. Recently, it has been demonstrated that retinoids in solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules can decrease degradation, improve targeting and enhance efficacy for the treatment of skin disorders. This article focuses on the formulation, fabrication, characterization and in vitro/in vivo evaluation of solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules loaded with retinoids for skin administration. Furthermore, the incorporation of these lipid nanoparticles into secondary vehicles is discussed.
Assuntos
Lipídeos/química , Nanopartículas/química , Retinoides/administração & dosagem , Retinoides/química , Administração Cutânea , Animais , Humanos , Pele/metabolismo , Absorção CutâneaRESUMO
La Hepatitis C es uno de los principales problemas de salud a escala mundial. Objetivo: Medir la prevalencia de hepatitis C y algunos factores de riesgo asociados en la comunidad. Métodos: Se realizó en los municipios Marianao y Playa en Ciudad de La Habana una encuesta sero-epidemiológica a una muestra aleatoria de 642 habitantes para identificación de anticuerpos al virus de hepatitis C (anti-VHC) por inmunoensayo y estudio de algunos factores de riesgo. Además se realizó la prueba RT-PCR para confirmar la viremia a los casos positivos y la prueba del VIH para identificar coinfección. Resultados: Se encontraron 4 casos con anticuerpos VHC, para una prevalencia general de 0.6% y un intervalo de confianza 95% (IC 95%) entre 0.19 1.7 correspondiendo al municipio de Marianao una prevalencia de 0.3% (IC 95%: 0.01- 1.95) y a Playa 0.9% (IC 95%: 0.24 3.0) no identificando casos de coinfección con el Virus de Inmunodeficiencia Humana (VIH). La prevalencia en el grupo de 5 a 11 años de edad fue 1.6% (IC 95%: 0.08-10.1). Entre 40 a 49 años la prevalencia fue del 1.6% (IC 95%: 0.27- 6.14) al registrar 2 casos, únicos además con infección activa para un 50% del total de infectados en la comunidad. Entre adultos mayores (50-59 años) la prevalencia fue de 1% (IC 95%: 0.05-6.97). En el análisis de regresión logística multivariada los factores de riesgo más asociados en mayores de 11 años de edad fueron el cambio de pareja sexual (OR: 3.97; IC 95%: 0.35-44.71) y la transfusión sanguínea (OR: 10.57; IC 95%: 0.94 -118.55), aproximándose esta última a tener un valor significativo (p=0.055). Conclusión: La prevalencia en la comunidad de VHC fue baja estando mayormente asociada a antecedentes de transfusión sanguínea