The immunomodulatory effect of saikosaponin derivatives and the root extract ofBupleurum kaoi in mice

The saikosaponins -a(SSa), -d(SSd), -f(SSf), crude saponin mixture (CSM) and H 2 O-layer components (HLC) which were isolated from the root of Bupleurum kaoi Liu, Chao et Chuang (Umbelliferae), demonstrated an immunomodulatory effect. Mice of the BALB/c strain were injected peritoneally with drugs to assess immune responses weekly over a 4 week period. The results showed that the mean ratio of thymus weight to body weight increased during week 1 but declined gradually thereafter; the ratio of helper T-cells to suppressor T-cells (Th/ Ts) from mice treated with SSf and HLC gradually increased; however, in mice treated with SSa, SSd and CSM, the ratio rose to a maximum at week 3 and then decreased; the IL-2 level of treated mice was significantly higher than that of the control group throughout the test period; the ratio of spleen weight to body weight in all drug treated groups increased weekly; the activity of B-cell stimulation in mice was promoted week by week; levels of IgA, IgG and IgM in serum of SSd and SSa treated animals increased. An in vitro study, involving stimulation of IL-1 demonstrated the following order of potency: SSd > SSa, 23-O-AcSSa and CSM > SSf and HLC.