CLOSTRIDIUM-PERFRINGENS EXOTOXINS .4. INHIBITION OF THETA-TOXIN INDUCED HEMOLYSIS BY STEROIDS AND RELATED COMPOUNDS

  • 1 January 1976
    • journal article
    • research article
    • Vol. 46  (1) , 45-50
Abstract
The inhibitory powers of 32 samples of steroids and their related compounds on .theta.-toxin induced [sheep erythrocyte] hemolysis were assayed. Apparent I50 [50% inhibition] value of cholesterol [the cell membrane toxin binding substance], the most potent inhibitor, was 0.022 .mu.M. Inhibitory powers of sterol acetates were not > 1/10 of those of the corresponding sterol, and steroids without 3-hydroxyl group hardly inhibited the hemolysis; the 3-hydroxyl group of sterols apparently plays an important role in the inhibition. The inhibitory power of sterols was strongly affected by steric situation of the 3-hydroxyl group tetracyclic rings. .theta.-Toxin apparently binds to the .beta.-side of the tetracyclic rings but not to the .alpha.-side. A methylsterol and pentacyclic triterpens with a 3-hydroxyl group also inhibited hemolysis, but steroids and their related compounds with a hydrophylic or without a hydrophobic group at their ring D had little, if any, inhibitory power.

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