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-1ß 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.

Galactomannan from Schizolobium amazonicum seed and its sulfated derivatives impair metabolism in HepG2 cells.

This study evaluated the effects of native galactomannan from Schizolobium amazonicum seeds and its sulfated forms on certain metabolic parameters of HepG2 cells. Aqueous extraction from S. amazonicum seeds furnished galactomannan with 3.2:1 Man:Gal ratio (SAGM) and molar mass of 4.34×105g/mol. The SAGM fraction was subjected to sulfation using chlorosulfonic acid to obtain SAGMS1 and SAGMS2 with DS of 0.4 and 0.6, respectively. Cytotoxicity of SAGM, SAGMS1, and SAGMS2 was evaluated in human hepatocellular carcinoma cells (HepG2). After 72h, SAGM decreased the viability of HepG2 cells by 50% at 250µg/mL, while SAGMS1 reduced it by 30% at the same concentration. SAGM, SAGMS1, and SAGMS2 promoted a reduction in oxygen consumption and an increase in lactate production in non-permeabilized HepG2 cells after 72h of treatment. These results suggest that SAGM, SAGMS1, and SAGMS2 could be recognized by HepG2 cells and might trigger alterations that impair its survival. These effects could be implicated in the modification of the oxidative phosphorylation process in HepG2 cells and activation of the glycolytic pathway.

Antioxidant effect of 1,3,4-thiadiazolium mesoionic derivatives on isolated mitochondria.

Mesoionic compounds have shown antitumor and citotoxic activity against different tumor cells lines, which has been attributed to their physical and chemical characteristics. Among these compounds, the 1,3,4-thiadiazolium-2-phenylamine derivatives have been highlighted due to their important anti-melanoma activity. In this work, the effects of three derivatives that belong this class, MI-J, MI-4F and MI-2,4diF, on the oxidative stress parameters were evaluated using rat liver mitochondria. All the derivatives prevented natural and calcium induced oxidation of pyridine nucleotides at lower concentrations (6.5 and 32.5nmol/mg protein). The calcium uptake was inhibited by all the derivatives at higher concentrations (65 and 130nmol/mg protein), whereas the cation efflux was inhibited only by the MI-J (52%) and MI-4F (50%), possibly by inhibiting the formation of the permeability transition pore (PTP) by 100% and 50%, respectively, as observed in the same experimental conditions. MI-2,4diF did not inhibit the mitochondrial permeability transition or calcium efflux. The enzymatic activity of glutathione reductase, glutathione peroxidase and catalase was not affected by any derivative, but superoxide dismutase was inhibited by all the derivatives. MI-J inhibited enzyme activity significantly (85%) at the highest concentration (130nmol/mg protein); on the other hand, their activity was less affected by fluorine derivatives (MI-4F-20% and MI-2,4diF-32%). These results suggest that these derivatives exert antioxidant effects on isolated mitochondria.