Stimulation of dendritic cell maturation and induction of apoptosis in lymphoma cells by a stable lectin from buckwheat seeds.

The present study aims to purify and characterize lectin from tartary buckwheat seeds and study its properties as well as biological activities to determine its possible biomedical applications in promoting maturation and proliferation of peripheral blood DCs derived from healthy donors and to study the effect of inducing apoptosis in human leukemia U937 cells. A novel tartary buckwheat lectin (TBL) protein, purified from tartary buckwheat seeds, showed a single band with a molecular mass of 65 kDa in SDS-PAGE. The purified TBL hemagglutinated both human and animal erythrocytes and showed preference for blood type O and the rabbit blood type. TBL is active at up to 60°C, and it is acid- and alkali-stable. TBL (25 µg/mL) combined with 5 x 10(-5) M rhIL-4 promotes maturation and proliferation of peripheral blood dendritic cells (DCs), which is stronger than that promoted by rhTNF-α (20 ng/mL). Exposure of DCs to 50 µg/mL TBL for 48 h resulted in extensive upregulation of maturation markers CD83 and CD40. These TBL-DCs were capable of producing several pro-inflammatory cytokines such as interleukin-10 (IL-10) and interleukin-12 (IL-12). The results of the treatment of human leukemia U937 cells with TBL in doses of 12.5, 25, 50, and 100 µg/mL showed that tartary buckwheat-derived lectin induces apoptosis in a dose-dependent manner. Our results encourage the use of tartary buckwheat and tartary buckwheat-derived lectins as immunopotentiating foods, targeted to strengthen immune responses and display a potential dietary supplement for cancer prevention.

Rutin, quercetin, and free amino acid analysis in buckwheat (Fagopyrum) seeds from different locations.

In this study, five common buckwheats and nine tartary buckwheats grown at different locations were analyzed for the contents of rutin, quercetin, and amino acids by high-performance liquid chromatography and spectrophotometry. The rutin content was higher than quercetin in buckwheat seeds. Rutin content was in the range from 0.05 (0.05 g per 100 g dry seeds) to 1.35% of buckwheat seeds. Quercetin content varied from 0.01 to 0.17% and in some common buckwheats it was even difficult to detect. Comparatively, tartary buckwheat seeds contained more rutin and quercetin than common buckwheat seeds. Meanwhile, the bran has higher rutin content than the farina in tartary buckwheat seeds, with a respective content of 0.45 to 1.19% and 0.14 to 0.67%. It was found that amino acid contents were around 1.79 to 12.65% (farina) and 5.74 to 7.89% (bran) in common buckwheats, and 1.73 to 5.63% (farina) and 2.64 to 16.78% (bran) in tartary buckwheat seeds. The highest total rutin content was found to be 1.35% in tartary buckwheat seeds from Sichuan, China. The highest total amounts of amino acid were detected to be 20.13% in tartary buckwheat seeds from Changzhi, Shanxi Province (China). Our results suggested that food products made of whole-buckwheat flour are healthier than those made of fine white flour.