The herbal medicine compound falcarindiol from Notopterygii Rhizoma suppresses dendritic cell maturation.

Dendritic cells (DCs) are important for regulating the immune response. We report an herbal medicine compound called falcarindiol that affects DC function. Ethanol extracts of 99 crude drugs that are the main components of 210 traditional Japanese medicines (Kampo medicine) approved by the Ministry of Health, Labor and Welfare in Japan were prepared and screened using the murine epidermal-derived Langerhans cell line XS106. Notopterygii Rhizoma strongly suppressed major histocompatibility complex (MHC) class II expression in XS106 cells. Activity-guided fractionation led to the isolation and identification of falcarindiol as a principal active compound in Notopterygii Rhizoma. Falcarindiol (1-5 microM) dose-dependently suppressed MHC II expression in XS106 cells. Fresh-isolated bone marrow-derived DCs were examined for the production of MHC II, CD80, CD86, interleukin (IL)-12p70, and IL-10. Treatment of bone marrow-derived DCs with 5 muM falcarindiol significantly inhibited lipopolysaccharide-induced phenotype activation and cytokine secretion and inhibited MHC II expression by CD40 ligation, but not phorbol 12-myristate 13-acetate + ionomycin or IL-12. Falcarindiol inhibited DC maturation by blocking the canonical pathway of nuclear factor-kappaB and phosphorylated p38. Topical application of 0.002 and 0.01% falcarindiol before sensitization dose-dependently suppressed delayed-type hypersensitivity to ovalbumin (p < 0.01). Falcarindiol induces immunosuppressive effects in vitro and in vivo and might be a novel therapy for autoimmune or allergic diseases.

Novel functions of herbal medicines in dendritic cells: role of Amomi Semen in tumor immunity.

Dendritic cells (DCs) have a major role in regulating immune responses, including tumor immunity and peripheral tolerance. In the present study, we identified novel functions of herbal medicines in DCs by screening 99 herbal medicines, most of which are among the 210 Chinese medicines approved by the Ministry of Health, Labour, and Welfare, Japan. Ethanol extracts were prepared, and a murine epidermal-derived Langerhans cell line, XS106, was used to screen the 99 extracts by analyzing major histocompatibility complex (MHC) class II expression. Amomi Semen (amomum seed), Polyporus (polyporus sclerotium), and Plantaginis Semen (plantago seed) potently activated XS106 and were selected for further analysis. The effects of these extracts on bone marrow-derived DCs (BM-DCs) generated in vitro were then analyzed using surface phenotype (MHC class II, CD80, and CD86) and interleukin (IL)-12p70 production as indicators. BM-DCs treated with Amomi Semen extract exhibited activated phenotypes and secreted IL-12p70. The activation level was similar to that induced by lipopolysaccharides. Finally, an E.G7-OVA tumor model (E.L4-OVA transfectant) was used to examine the anti-tumor effects of Amomi Semen extract. Vaccination of mice with a subcutaneous injection of BM-DCs treated with Amomi Semen extract and OVA peptide significantly inhibited the growth of tumor cells and prolonged survival time compared to controls. Furthermore, therapeutic effects were observed on established tumors. The inhibition rates for both the prophylactic and therapeutic protocols were comparable to those of lipopolysaccharides. These results indicate that Amomi Semen extract potently activate DCs and is potentially useful for DC vaccination.