Effects of two polysaccharides from Lepidium meyenii (maca) on intestinal immunity and inflammation in vitro .

In our previous studies, two polysaccharides (MC-1 and MC-2) were identified in the roots of maca ( Lepidium meyenii ). In this study, the effects of these two polysaccharides on intestinal immunity and inflammation were assessed using intestinal epithelial cells, i.e. , Caco-2 cells. The levels of cytokines and tight junction proteins were measured using ELISA and qPCR, respectively. The results showed that MC-1 and MC-2 were difficult to be absorbed in the Caco-2 cell monolayer, but promoted the secretion of IL-8, IL-10, IL-12, and INF-γ in the Caco-2 cells, and the secretion of TNF-α, IL-6, and NO in macrophages (RAW264.7 cells) via the Caco-2 cell monolayer. Additionally, both polysaccharides inhibited damage induced by lipopolysaccharides to the densification of the Caco-2 monolayer membrane by regulating the expressions of TLR4, ZO-1, and occludin. Furthermore, the secretion of inflammatory factors such as TNF-α, IL-8, and INF-γ was inhibited, and the secretion of the anti-inflammatory factor, IL-10, increased. The results indicated that MC-1 and MC-2 can activate intestinal immunity and alleviate intestinal inflammation in vitro .