We conducted screening on Chinese medicinal herbs which had used empirically without scientific verification thereof to examine their anti-complementary activity by hemolytic complementary assay (TCH_(50)). Among 55 kinds of herbs. several herbs showed relatively potent anti-complementary activity which decreased TCH_(50), more than 70% in comparison with control. Then, hot water extracts of the following herbs, Curcuma ayomatica, Areca catechu, Gleditsiae spina, Euonymus alata, Acanthopanax senticosus. Lonicera japonica, Aconitum carmichaeli. Curcuma zedoaria and Cinnamoum cassia, which were shown relatively potent anti-complementary activity were partially purified and analysed their chemical properties. These activities were resistant to digestion with pronase but decreased by treatment with NaIO₄. Active fraction contained uronic acid, hexose and protein in their molecule and was non-dialyzable. These results may indicate that the complement activating ability in their herbs is due to polysaccharide.
Furthermore, the anti-complementary activity of Areca catechu which was showed most potent activity, was re duced partially in the absence of the Ca^(++) ion. After incubation of the normal human serum with partially purified polysaccharide of A. catechu in the absence of Ca^(++) ion, a cleavage of C3 in the serum was found to have occured through immuno-electrophoresis using goat anti-human C3 serum. These results indicate that the mode of complement activation by polysaccharide of A. catechu is via both the alternative and classical pathway. Also, the activity of this polysaccharide on the complement system was not due to LPS contamination.
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