The action of the benzopyrones on an experimental model of lymphoedema: a contribution to their mode of action.

A number of preparations containing benzopyrones are used clinically as a therapy for lymphoedema; however, their exact mode of action is not well known. This work presents evidence which indicates that, as in the treatment of thermally induced oedemas, the benzopyrones work by enhancing the lysis of the accumulated proteins. This is evidenced by reduced levels of total protein in the extracellular compartment of the skin, while peptides and amino acids were increased in the serum at 6 and 12 h respectively after the drug's administration. Failure to observe very marked increases in peptides and amino acids at other times in the serum and skin was attributed to the rapid incorporation of these into the large number of maturing phagocytes which enter the lymphoedematous tissues. Likewise, protease activity levels were not elevated as expected. This possibly was the consequence of a number of factors including serum deactivation, inhibition of release and membrane stabilization.