Immunomodulatory effect of polysaccharides isolated from Lonicera japonica Thunb. in cyclophosphamide-treated BALB/c mice

Lonicera japonica (L. japonica) is utilized as foods and healthy drink around the world. Until now, the immunomodulatory activity of polysaccharides from L. japonica (LJP) is little studied. In our previous work, LJP was fractionated to a neutral component (LJP-N) and an acidic component (LJP-A) by a DEAE-Cellulose column, and LJP-N was a starch-like polysaccharide and LJP-A was a pectic polysaccharide. In this study, LJP-N and LJP-A were investigated for their immunomodulatory effect, and the protective effect of these two polysaccharide fractions against immune injury by cyclophosphamide (CTX) in BALB/c mice was evaluated. Results showed that when compared with CTX group, LJP fractions, especially for LJP-A (200 mg kg−1) can enhance the immune function, improve atrophy of the lymphoid organs thymus and spleen (the increased approximately 1.8- and 1.6-fold), increase the phagocytic function of macrophages (increased approximately 1.7-fold), increase the secretion of cytokines (the levels of IL-6, IL-2, and TNF-α increased approximately 2.5-, 2.0-, and 1.4-fold) and immunoglobulins levels (the levels of IgM and IgG increased approximately 1.2- and 1.7-fold) in serum, and enhance the cytotoxic activity of NK cells (increased approximately 3.5-fold). Taken together, the present results suggest that LJP-A, rich in uronic acid, with a molecular weight of 400 kDa, may be a potential candidate as the functional foods.