Antitumor and immunomodulatory activity of polysaccharides from the roots of Actinidia eriantha.
The roots of Actinidia eriantha Benth (Actinidiaceae) have been used for cancers in the Chinese folk medicine. The present study aimed at evaluating the antitumor potentials of the polysaccharides from the roots of Actinidia eriantha and elucidating their immunological mechanisms by determining the effects on the growth of tumor transplanted in mice and the immune response in tumor-bearing mice. The total polysaccharide AEP and fours purified polysaccharides AEPA, AEPB, AEPC and AEPD were isolated and purified from the roots of Actinidia eriantha by hot water extraction, ethanol precipitation, dialysis and gel filtration. Their effects on the growth of mouse transplantable tumor, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL), production of cytokines from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice were measured. AEP and four purified polysaccharides could not only significantly inhibit the growth of mouse transplantable tumor, but also remarkably promote splenocytes proliferation, NK cell and CTL activity, IL-2 and IFN-gamma production from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice. The antitumor activity of AEP and four purified polysaccharides might be achieved by improving immune response, and the composition of the monosaccharides, uronic acid contents and molecular weight could affect their antitumor and immunomodulatory activity.