Sulfated Mesona chinensis Benth polysaccharide enhance the immunomodulatory activities of cyclophosphamide-treated mice

[Display omitted] •Sulfated Mesona chinensis Benth polysaccharide (SMP) activated T and B lymphocytes.•Toll-like receptor 4 is the receptor for the immunomodulatory activity of SMP.•SMP protected mice against the immunosuppression effects caused by Cy.•SMP can be developed as a potential immunoregulatory agent in functional foods. A sulfated polysaccharide (SMP) from the Mesona chinensis Benth was successfully obtained and its immunomodulatory effects were evaluated. Results showed that SMP exhibited the proliferation effects in splenocytes in vitro and ameliorated the impaired of splenocytes in Cy-treated mice. SMP induced the production of nitric oxide (NO), interleukin (IL) −2, interferon-γ (IFN-γ), increased the expression of antioxidant enzymes (SOD and CAT), and reduced the production of malondialdehyde (MDA) in Cy-treated mice, as well as improved the blood index, body weight and organ index. In addition, SMP enhanced the viability of RAW264.7 macrophages and increased the secretion of IL-6, IL-1β and tumor necrosis factor-α (TNF-α) and production of NO in RAW264.7 cells. Furthermore, SMP binds to TLR4 (Toll-like Receptor 4) to promote RAW264.7 to produce cytokines, thereby exerting immunoregulatory function. These data indicated that SMP act a pivotal part in immunomodulatory and could be used as functional foods.