polysaccharide k

Polysaccharide K (PSK), also known as Krestin, is a protein-bound beta-glucan polysaccharide extracted from the mycelium of the mushroom *Trametes versicolor* (also known as *Coriolus versicolor* or "turkey tail"). It has been widely used in Japan and other parts of Asia for over 30 years as an adjuvant immunotherapeutic agent in cancer treatment. PSK is approved as a pharmaceutical-grade medicine in Japan and has been used primarily to manage gastric, colon, and colorectal cancers alongside chemotherapy. Its mechanism of action involves immunomodulation—stimulating T cell proliferation; inducing secretion of cytokines such as IL-8 and TNF-alpha by monocytes; enhancing natural killer (NK) cell activity; improving CD4+ T cell function; preventing cyclophosphamide-induced immunosuppression; inducing apoptosis in tumor cells; and increasing MHC class I expression. The precise molecular mechanisms remain incompletely elucidated but are believed to involve both direct anti-tumor effects and potentiation of immune surveillance[1][2][3][5][6][8].

Brand names

Krestin

Other names

polysaccharide kPSKKrestinprotein-bound polysaccharide KCoriolus versicolor extractTrametes versicolor extractturkey tail glucan