Immunomodulatory effect of citrus pectin and modified citrus pectin on cytokine production by spleen in Balb/c mice

Abstract

Pectin is present in the cell wall of different vegetables and fruits. It is an important source of dietary fibers in human nutrition. Pectin is composed mainly of homogalacturonan, rhamnoagalacturonan I and rhamnogalacturonan II. Endogenous gastrointestinal enzymes are not able to degrade pectin. However, it is degraded in the colon by the microflora. Beside its importance in the plant cell wall, pectin possesses many beneficial effects on human health. It has been used to treat diarrhea, to decrease cholesterol level, to possess anti-oxidative, antibacterial and anti-cancers effects. Studies on the effects of pectin and pectic polysaccharides on the immune system are limited. This study investigates the immunomodulatory effects of citrus pectin and modified citrus pectin in vivo on the levels of IFN-γ, TNF-α, IL-1β, IL-4, IL-10 and IL-17 in the spleen of Balb/c mice at 3 weeks post feeding. Different doses (1.5, 3 and 5%) of citrus pectin and modified citrus pectin were given to Balb/c mice continuously in the drinking water for twenty-one days. Then, the levels of cytokines in the spleen were assessed using ELISA tests. The results have shown that modified citrus pectin is able to upregulate the levels of IFN-γ, TNF-α and IL-17 suggesting that it favors Th1 and Th17 responses known to be mainly pro-inflammatory. Consequently, our data pave the road for further studies to investigate the potential clinical implications of modified citrus pectin.