Extraction of water-soluble polysaccharides from kidney beans and examination of their protein dispersion and stabilization properties under acidic conditions.

The extraction conditions of kidney bean water-soluble polysaccharides (SKPSs) from kidney bean fibers were examined. The factors such as temperature, pH, and time were combined to derive the conditions for obtaining high yields of high molecular mass polysaccharides. The optimal extraction temperature, time, and pH were 120 °C, 30 min, and 9, respectively. Under these conditions, the yield of SKPS (SKPS9) obtained was as high as 26.4%. The weight average molecular mass of SKPS9 measured using size exclusion chromatography equipped with a multi-angle laser light scattering detector was 2,530 kg/mole. The main constituent sugars of SKPS9 were arabinose (67.2%) and galacturonic acid (15.6%). SKPS9 carbohydrate molecules observed using a scanning probe microscope showed the mixed structures of a multi-branched structure, whose sugar chains extended outward from the center to the periphery of the molecule, and a little-branched straight chain structure. SKPS9 had protein dispersing and stabilizing properties under acidic conditions. In the acidified milk system containing 3% non-fat milk solids, 0.4% SKPS9 was able to maintain a mono-modal distribution of fine protein particles in pH level ranging from 3.8 to 4.4. This work suggests the potential for the creation of a value added ingredient from kidney bean.

Suppressing effects of dietary supplementation of soybean trypsin inhibitor on spontaneous, experimental and peritoneal disseminated metastasis in mouse model.

The modifying effects of a Kunitz trypsin inhibitor (KTI) and a Bowman-Birk trypsin inhibitor (BBI), purified from soybean trypsin inhibitor, as dietary supplements on experimental and spontaneous pulmonary metastasis of murine Lewis lung carcinoma 3LL cells as well as peritoneal disseminated metastasis model in human ovarian cancer HRA cells were investigated in i.v., s.c. and i.p. injection models in mice. Seven groups of female C57BL/6 or nude mice were fed a basal diet (control group) or the basal diet supplemented with KTI or BBI (5, 15, or 50 g/kg). Here we show that, in an in vivo spontaneous metastasis assay, the diet supplementation with KTI (15 and 50 g/kg), but not with BBI, for 28 days immediately after s.c. tumor cell inoculation significantly inhibited the formation of lung metastasis in C57BL/6 mice in a dose-dependent manner. The inhibition of lung metastasis was not due to direct antitumor effects of KTI. In an in vivo experimental metastasis assay, the diet supplementation with KTI or BBI for 21 days after i.v. tumor cell inoculation did not reduce the number of lung tumor colonies. In addition, KTI (15 or 50 g/kg) treatment in a peritoneal disseminated metastasis model of HRA cells resulted in a 40% reduction in total tumor burden when compared with control animals. Immunoblot analysis revealed that KTI specifically reduced expression of uPA protein as well as phosphorylation of MAP kinase and PI3 kinase proteins in the cells stimulated with agonists (G-CSF for 3LL cells or TGF-beta1 for HRA cells). These results suggest that dietary supplementation of KTI more efficiently regulates the mechanism involved in the entry into vascular circulation of tumor cells (intravasation) than in extravasation during the metastatic process. KTI treatment may also be beneficial for ovarian cancer patients with or at risk for peritoneal disseminated metastasis; it greatly reduces tumor burden in part by inhibiting phosphorylation of MAP kinase and PI3 kinase, leading to suppression of uPA expression.