Dendrobium officinale is widely consumed owing to its numerous beneficial effects. We aimed to characterize polysaccharides of Dendrobium officinale (DOP) from the stems of Dendrobium officinale Xianhu 2 and clarify whether it benefit the intestinal microbiota and the immune system. The DOP weighed 291 kDa and comprised mannose, glucose, galactose, and rhamnose at 59.31:33.31:1.00:0.51 M ratio. In in vitro/vivo studies, DOP significantly increased benign intestinal microbe proportion (Lactobacillus, etc.), but reduced harmful bacteria (Escherichia_Shigella) (P < 0.05), and significantly increased butyric acid production (P < 0.05). Concentrations of 2 g/L DOP for in vitro fermentation and 100 mg/kg body weight for the mouse model were effective. In mice, DOP significantly reduced CRP, CD3, CD4, and TNF-α levels and increased C4 levels (P < 0.05). DOP might influence the immune system indirectly through regulation of the gut microbiota. Its possible regulation mechanism was that DOP reduced CD4+ Th cells proliferation so that reduced the secretion of TNF-α.
Keywords: Chemical structure; Dendrobium officinale polysaccharide; Extraction; Gut microbiota; Immune system; Mice model.
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