The need for novel drugs for the treatment of autoimmune diseases is rising since available pharmaceuticals are often characterized by severe side effects and a limited efficacy [1]. Therefore, we investigated the immunosuppressive potential of a library of 435 extracts prepared from plants used in Traditional Chinese Medicine.Immunosuppressive activity of extracts was assessed in a proliferation-based assay utilizing physiologically relevant anti-CD3 and anti-CD28 stimulated primary human T lymphocytes [2]. Among others, an ethyl acetate extract of Artemisia argyi (Asteraceae) was found to be highly active. The observed inhibitory effect on T cell proliferation was not based on toxic effects of the extract, as shown by apoptose-/ necrosis induction analysis of T lymphocytes.
The A. argyi extract was submitted to HPLC-based activity profiling [3]. A T cell proliferation assay identified two active regions in the chromatogram, and a highly active peak with an IC50 of 0.25 µg/ml was identified in the first region. Fractionation of this peak finally determined (1R,2S,3R,4S,5S,6S,7S,10R)-canin (1) and two seco-tanapartholides as constituents responsible for most of the activity. IC50 values of 0.71 µg/ml for 1, and 0.24 µg/mland 0.28 µg/ml, respectively, for the (4R,5R,6S,7S)- and (4S,5S,6S,7S)-seco-tanapartholides (2 and 3), respectively, qualify these compounds as potential immunosuppressive leads. Further investigations focusing on the mode of action are underway.
1. Steinman L. Immune Science 2004; 305: 212
2. Quah BJC, Parish CR. J Visualized Exp 2010: 2259
3. Potterat O, Hamburger M. Planta Med 2014; 80: 1171-1181