Immunomodulating activity of Chinese medicinal herbs and Oldenlandia diffusa in particular

The effect of eight different Chinese medicinal herbs (CMHs) on lymphocytes was studied in vitro using murine spleen cells. Among the studied eight CMHs, Astragalus membranaceus and Oldenlandia diffusa markedly stimulated murine spleen cells to proliferate. The responder cells for CMHs were B cells, because the response was depleted by the treatment of spleen cells with anti-immunoglobulin (Ig) antibody and complement and after purification by nylon wool column. This response was not due to contamination by lipopolysaccharide (LPS), because CMHs could stimulate C3H HeJ spleen cells which are low responders to LPS. CMHs enhanced the production of Ig. CMHs also enhanced the induction of allo-antigen specific cytotoxic T lymphocytes. However, CMHs had no effect on natural killer cells. Furthermore, CMHs stimulated macrophages to produce interleukin-6 and tumor necrosis factor. The electroelution of the proteins from SDS-PAGE gel showed that the active components of Oldenlandia diffusa had an apparent molecular weight of 90 200 kD and were sensitive to pronase E and NaIO₄ treatment, suggesting glycoproteins in nature. These results suggest that CMHs have immunomodulating activity in vitro and this activity could be used clinically for the modulation of immune responses.