Immunosuppressive activity of the ethanol extract of Siegesbeckia orientalis on the immune responses to ovalbumin in mice.Chem Biodivers. 2006 Jul; 3(7):754-61.CB
The in vitro and in vivo immunosuppressive activity of the ethanol extract of Siegesbeckia orientalis (EESO) was studied on the immune responses in mice. EESO significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. ICR Mice were immunized subcutaneously with ovalbumin (OVA) on days 0 and 14. Beginning on the day of immunization, the mice were administered intraperitoneally with EESO at a single dose of 0.25, 0.5, and 1.0 mg at intervals of 7 days. On day 28, OVA-specific antibodies in serum, and mitogen- and OVA-induced splenocyte proliferation were measured. EESO significantly suppressed Con A-, LPS- and OVA-induced splenocyte proliferation in the OVA-immunized mice in a dose-dependent manner. The OVA-specific serum IgG, IgG1, and IgG2b levels in the OVA-immunized mice were also significantly reduced by EESO. Moreover, reducing effect on the IgG1 antibody of EESO at the dose of 1.0 mg was more significant than that of cyclosporin A (CsA; positive drug). The results suggest that EESO could suppress the cellular and humoral response to ovalbumin in mice, and deserve further investigations to be developed as immunosuppressant.