Immunomodulatory factors in Cistanche salsa

Cistanche salsa (C.A. Meyer) G. Beck, Orobanchaceae is a parasitic plant that is used as an oriental medicinal tonic in Japan. In our previous study, we found that C. salsa extract enhanced the production of both IgM and IgG in human lymph node lymphocytes. Furthermore, C. salsa dialysate (CSD) prepared using a dialysis membrane with a 3,500-Da molecular weight cut-off enhanced IgM production in the human B-cell line BALL-1; in addition, it induced slight cell proliferation. However, in contrast, CSD induced growth inhibition accompanied by apoptosis in the human Burkitt's lymphoma cell line Namalwa. These results indicate the possible presence of active constituents in CSD that are specific to lymphocytes. Thus far, the chemical properties of these constituents have not been elucidated. In this study, we investigated the chemical properties of the active constituents in CSD. Both the abovementioned activities in B-cell lines were not inactivated by autoclave treatment of CSD. Using gel filtration column chromatography, we found that the peaks of the active fractions were concentrated in different fractions. Our results suggest that there are at least 2 types of active constituents in CSD, and they may be polysaccharides since they are water soluble high molecular weight constituents and thermostable.