Detection of Lewis a antigenic determinants in Chinese medicinal herbs

Two Chinese medicinal herbs, Leonurus sibiricus L. and Carthamus tinctorius L., were found to have high levels of Lewis a (Lea)-like determinants. The water-soluble extracts specifically inhibited hemagglutination, hemolysis, and lymphocyte cytotoxicity directed against Lea. They did not inhibit Leb nor other specificities detected on lymphocytes, resulting from the interaction of Lewis, Secretor, and ABO systems such as A1Leb and A1Led. The activity was nondialyzable, resistant to boiling and proteolytic enzymes, but was destroyed by periodate. It was suprising that an Lea substance, previously found in human secretions, was also present in flower abstracts.