Induction of Neutrophil Accumulation by Vegetable Juice

Yam contributes to improvement of glucose metabolism in rats

To investigate whether yam improves glucose metabolism, yam-containing diets were given to Wistar rats. In a short-term experiment, fasted-rats were given 1.0 g of a control and 20% yam-containing diets. At 60 min after start of the feeding, glucose level in the yam diet group was lower or tended to be lower than that in the control diet. Insulin levels at 30 min and 60 min were significantly lower than those in the control group. In a long-term experiment, a normal diet (N) or 25% high fat diets with (Y) or without 15% yam powder (HF) were given to rats for 4 weeks. At 4 weeks, in an oral glucose tolerance test, the area under the curve (AUC) of plasma glucose level was higher in the HF group than that in the N group, whereas those in the Y groups did not differ from that in the N group. Glycosylated hemoglobin levels had similar tendency to the AUCs. Plasma leptin levels in the Y groups were significantly higher than that in the N group. In conclusion, yam may contribute to improvement of glucose metabolism. Additionally, we speculated that leptin level is possibly involved in the insulin-response to yam diets.

Effect of Dietary Administration of Bananas on Immunocytes in F1 Hybrid Calves

The effect of dietary administration of bananas on immunocytes in calves was investigated. Twenty Fl hybrid calves were used in this study (treated group n=10, control group n=10). Banana (2 g/kg BW) was administered to the calves for 5 days. Leukocyte subsets were examined on days 0, 5, 10, and 15. The numbers CD3+, (CD3+)CD45R-, and (CD3+)TcR+ cells significantly increased between day 0 and day 5 in the treated group (P<0.01), and were significantly higher on day 5 in the treated group relative to the control group (P<0.05). These data showed that feeding banana to calves increased T-lymphocytes, suggesting it might be possible to enhance protective functions against infections.

Induction of interferon-gamma (IFN-gamma) and T helper 1 (Th1) immune response by bitter gourd extract

Mice were inoculated intraperitoneally wih 34 different types of vegetable juices, and interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were measured as markers for the induction of Th1 and Th2 cells, respectively. Serum IFN-gamma level was markedly increased in mice inoculated with bitter gourd (Momordica charantia) juice, but IL-4 levels were not increased with any of the 34 vegetable juices. Testing of the various components of bitter gourd, including peel, pulp, and seed, showed that the pulp induced the highest levels of IFN-gamma. Trial immunogen including the heat extract of the pulp induced specific IgG(2a) antibody of the mice serum inoculated with this immunogen. These results demonstrate that bitter gourd pulp induced IFN-gamma production and show its promise as a means of effective immunostimulatory therapy specific for Th1 cells and IFN-gamma production.

Induction of anti-inflammatory responses by dietary Momordica charantia L. (bitter gourd)

We assessed the immunomodulatory activity of Momordica charantia L. (bitter gourd), a vegetable that has been reported to possess various bioactivities. We examined the effect of bitter gourd on intestinal immunity by monitoring the TGF-beta and IL-7 secretion from Caco-2 cells and the IL-10 and IL-12 secretion from THP-1 cells that are used as in vitro models of the intestinal epithelium and monocyte/macrophages, respectively. We also determined the in vivo immunological responses of rats fed on bitter gourd for 3 weeks. We found that bitter gourd induced a decrease in the intestinal secretion of IL-7 and an increase in the secretions of TGF-beta and IL-10, these effects reflecting the bitter gourd-induced changes in systemic immunity, i.e., a decrease in the number of lymphocytes, increases in the populations of Th cells and NK cells, and increase in the Ig production of lymphocytes. Dietary bitter gourd may therefore induce both intestinal and also systemic anti-inflammatory responses.