RESUMO
Objective To elucidate the antitumor activity of exopolysaccharide from Aphanothece halophytica(EPAH).Methods The in vivo inhibition of EPAH on growth of tumor was performed by inoculation of S_(180) sarcoma cells into ICR mice.While in vitro activity against tumor cells was assayed by the growth inhibition of cell lines of S_(180) sarcoma,Smcc7721,and HeLa.The effects of EPAH on immune function were evaluated by the influence on the thymus,spleen,and the number of lymphocytes in blood stream,the influence on proliferation of lymphocytes,the killing activity of NK cells,and the production of NO,IL-1?,and TNF-?. Results EPAH inhibited in vivo S_(180) sarcoma growth with the highest inhibi-(tory) rate of 66.79% and 47.93% in the test mice of pretreatment and simultaneous treatment,respectively.EPAH also displayed in vitro activity against the test cell lines with the highest inhibitory rate being more than 60% at a concentration of 100 ?g/mL.EPAH was found to affect the immune function in mice including increasing the weight of thymus,spleen,and the number of lymphocytes in the blood stream,accelerating the proliferation of lymphocytes,enhancing the killing activity of NK cells,and stimulating the production of NO,IL-1?,and TNF? by macrophages.Conclusion EPAH is an effective antitumor(agent.) It inhibites the tumor cells directly and hence the growth of tumor.Its antitumor activity is probably realized by increasing the weight of immune organs and the number of immunocytes as well as lymphocyte proliferation,enhancing the killing activity of NK cells,facilitating the production of NO and related(cytokines) in tumor-bearing mice.
