Pectin from Brassica oleracea var. italica triggers immunomodulating effects in vivo

The immunomodulatory ability of pectins is related with structural features such as the degree of methyl-esterification and branching, as well as the molecular mass. The pectin FB, extracted from broccoli stalks (Brassica oleracea var. italica) had low molecular mass, 56% methyl-esterification and galactose as the main neutral sugar, sharing some characteristics with the modified citrus pectin (MCP), which has been extensively studied in vivo and in vitro due its immunomodulator potential. Considering that broccoli has an important role in the diet, the main objective of this study was to investigate the ability of FB in modulating the immune system in vivo. At concentrations 100-500 μg/mL, FB did not affect the viability of macrophages. Evaluations on morphology and phagocytic activity showed that FB (500 μg/mL) increased the number of activated macrophages by 39% and phagocytic activity by 30% within 48 h. FB (200 mg/kg) administered intraperitoneally increased the number of peritoneal macrophages in mice by 490% after 24 h and modulated these cells for an activated phenotype. In mice, oral administration of FB (200 mg/kg) stimulated lymphocytes from spleen and bone marrow proliferation. FB did not induce nitric oxide (NO) production by macrophages and also did not affect the levels of pro-inflammatory interleukins IL-1β and IL-12 by peritoneal macrophages, but induced the production of the anti-inflammatory interleukin IL-10. The results could suggest that the anti-inflammatory effects triggered by FB could be related to its degree of esterification and pointed this polysaccharide as a target for the development of new immunomodulatory drugs.