RESUMEN
A anfotericina B (AmB) é fármaco o padrão ouro para o tratamento de infecções fúngicas invasivas desde 1960, Entretanto, a anfotericina B apresenta elevada toxicidade, a qual manifesta-se mais frequentemente nos rins e no fígado, Sabe-se, desde 1985, que a auto-oxidação da AmB origina diferentes formas de espécies reativas oxidativas e estas, por serem tóxicas para a célula, seriam responsáveis, em parte, pela toxicidade, Diferentes estudos indicam que a hesperidina contribui por meio do decréscimo do estresse oxidativo, para a proteção renal e contra a injúria gerada pela isquemia, Tal fato e o envolvimento da AmB na geração de radicais livres tornam interessante a avaliação preliminar do efeito da hesperidina e AmB (isoladamente ou associadas) frente a espécies reativas do oxigênio e radicais livres, bem como o estudo das mesmas em modelos de citoxicidade, Frente ao ABTS+, a AmB apresentou IC50 igual a 0,0124mg/mL, mas quando associada à hesperidina este valor caiu para 0,0003mg/mL, Frente ao HOCl, a Amb apresentou IC50 igual a 0,0056, mas quando associada à hesperidina este valor caiu para 0,0023mg/mL, No ensaio com DPPH e radical ânion superóxido as amostras não foram efetivas, No ensaio com células endoteliais em cultivo (HUVEC), as associações reduziram a viabilidade celular, Estes resultados preliminares evidenciam a interação dos compostos com espécies reativas bem como indicam possibilidade de exacerbação do dano pela AmB na presença dos antioxidantes em um modelo in vitro...
Amphotericin B (AmB) is drug gold standard for the treatment of invasive fungal infections since 1960. However, amphotericin B has high toxicity, which manifests itself most often in the kidneys and in the liver. It is known, since 1985, that self-oxidation of AmB gives different forms of reactive oxidative species and these, being toxic to the cell, would be responsible, in part, by its toxicity. Different studies indicate that hesperidin contributes, through the reduction of oxidative stress, to protect against renal injury generated by ischemia. This fact and the involvement of AmB in the generation of free radicals make it interesting the preliminary evaluation of the effect of hesperidin and AmB (alone or associated) against reactive oxygen species and free radicals, as well as the study on models of cytotoxicity. Front ABTS+, AmB presented IC50 equal to 0.0124 mg/mL, but when it was associated to hesperidin this value has decreased to 0.0003 mg/mL. Front HOCl, Amb presented IC50 equal to 0.0056, but when it was associated to hesperidin this value has decreased to 0.0023 mg/mL. In the trials with DPPH and the superoxide anion radical samples were not effective. In the assay with endotelial cell culture (HUVEC cells), the association has decreased cell viability. These preliminary results demonstrate the interaction of the compounds with reactive species as well as indicate the possibility of damage exacerbation by AmB in the presence of antioxidants in an in vitro model...
Asunto(s)
Humanos , Anfotericina B , Antifúngicos , Hesperidina , Estrés OxidativoRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Synadenium grantii Hook f. has traditionally been used to treat various neoplastic diseases in southern Brazil. AIM OF STUDY: Evaluation of the antitumoural potential of Synadenium grantii latex against B16F10 melanoma cell line using in vitro and in vivo models, as well as a phytochemical study of the latex. MATERIALS AND METHODS: The in vitro antitumoural activity was performed using MTT and trypan blue assays with different latex concentrations (1.7 µg-7.0 µg/well and 1.22 mg-4.88 mg/well). Flow cytometry was used to determine the progression of the cell cycle. The in vivo activity was performed by subcutaneously injecting melanoma cells in the dorsum of C57BL6 mice, followed by treating the mice with a popular form of use of the latex (garrafada) administered orally. After sacrificing the animals, histological analysis of the organs was performed by hematoxylin-eosin staining. The phytochemical study of the latex was performed by NMR and chromatographic procedures and the extracts and isolated substances were evaluated by IR, 1D and 2D NMR analysis. RESULTS: The Synadenium grantii latex exhibited decreased cell viability of the melanoma line in a concentration and time-dependent manner, and also cell cycle arrest in the S-G2/M phase. The latex caused a 40% reduction in the volume of tumours of the mice with melanomas. Histological examination of the organs of these animals showed no differences between groups. The phytochemical investigation resulted in the isolation and identification of triterpene euphol and the steroid citrostadienol, which were tested against the strain of melanoma. Euphol showed no antitumoural activity, while the steroid citrostadienol showed reduced cytotoxic activity. CONCLUSION: The Synadenium grantii latex presented in vitro and in vivo cytotoxic effects with antitumoural activity against B16F10 melanoma cells.
