RESUMEN
BACKGROUND: The chemical characteristics of the exo-secretion from Phellinus linteus (referred to as exo-secretion) including the compositions of amino acids and monosaccharides were investigated. In addition, cytotoxicity of the exo-secretion on 5 tumor cell lines derived from human cancers and its antitumor activity against ascitic sarcoma-180 cells were examined. METHODS: The antitumor activity of exo-secretion from Phellinus linteus was determined by measuring parameters including tumor weight, life span of mice, chemotatic activity of leukocytes, counts of immune cells, and activity of cytokines. RESULTS: The exo-secretion from Phellinus linteus showed no direct cytotoxicity to the five tumor cell lines tested, but it had a strong antitumor activity against sarcoma-180 cells in ICR mice as measured by tumor weight and life span of mice. The exo-secretion stimulated the chemotaxis of leukocytes and production of immune cells and cytokines. CONCLUSION: These results suggest that the exo- secretion from Phellinus linteus do not act as a direct cytotoxic substance to cancer cells but as an immunomodulator.