Avaliação do potencial anticâncer de uma fração polissacarídica sulfatada extraída da alga marinha parda Dictyota caribaea em camundongos

Abstract

The marine environment is recognized as an important source of natural products. In this context, among the main sources of bioprospecting drugs are the seaweeds, because they synthesize bioactive and non-toxic molecules such as sulfated polysaccharides. Algae have a high concentration of polysaccharides which may have anticancer activity. Cancer is a major public health problem worldwide, and malignant neoplasms the second leading cause of death worldwide. Considering the need for new approaches to the treatment of cancer, new mechanisms of action are being exploited for the development of drugs to combat this disease. The present work aimed to evaluate the antitumor potential from a sulfated polysaccharide fraction extracted from brown seaweed Dictyota caribaea using models in vitro and in vivo. The cytotoxicity was tested in vitro by MTT assay against strain HCT-116 (colon cancer) at concentrations of 50 and 100 ug / ml. For in vivo assay Swiss female mice were used weighing between 28 and 30 g from the Central Animal Facility of the Federal University of Ceará (BIOCEN - UFC). This work was approved by the Animal Ethics Committee of the Federal University of Ceará (CEPA) (# NS50). Animals were divided into three groups (n = 8 per group) and subsequently treated for seven days with saline (control group), DCA 25 mg / kg / day or DCA 50 mg / kg / day (IP). Were also evaluated possible changes in biochemistry, hematological and histopathological parameters of organs (kidney, spleen and liver), as well as the tumor. A blood sample was collected for biochemical and hematological analysis at day 8 post tumor transplant. After euthanasia, the tumor and the orgains (spleen, kidneys and liver) was collected, weighed and histologically analyzed. DCA did not exhibit cytotoxicity, however the tumor growth was inhibited by 51%. The animals treated with DCA showed a significant increase in spleen weight and small changes in other organs. Furthermore, the amount of monocytes was reduced, but the total leukocyte count showed no difference between the control and DCA groups. The biochemical analysis of SGO-T and SGP-T of the treated animals showed changes, but the analysis of urea showed no difference between treatment and control. The decreased circulating of monocytes could be related to the migration of this cells to the tumor microenvironment and, generally, these results suggest that the DCA antitumor effect could be related with an immunomodulating effect.