K 76 carboxylic acid [ K 76 COOH,K-76 COONa,K-76 monocarboxylic acid,K-76 sodium carboxylate,K-76COOH,K76 COOH,K76COOH,MX-1 ] effective in blocking formation of chemotactic factor for tumor cells from human complement; oxidized product of sesquiterpene derivative K 76 from fungus Stachybotrys complementi; do not confuse with