Physiological activity of some organophosphorus compounds and their effects on the physico-chemical properties of model membranes.

The effect of the newly synthesized phosphonic compound dibutyl 2-octylamino-2-propanephosphonate (DBOP) on the growth of the aquatic plant Spirodela oligorrhiza and stability of red blood cells (RBC) and planar lipid membranes (BLM) was studied to determine its physiological activity and, if possible, correlate this activity to compound-induced changes in the mechanical properties of the model membranes. The measure of the phytotoxicity was the DBOP concentration causing 50% plant growth retardation, while measures of stability of model membranes were 100% hemolysis of RBC and a critical concentration of DBOP causing BLM destruction in no more that 3 min. These data were compared with those for dibutyl 1-butylamino-1-cyclohexanephosphonate (DBBC) and diethyl 9-butylamino-9-fluorenephosphonate (DEBF) known for their physiological activities. Both DBBC and DEBF influenced Spirodela growth significantly less than DBOP Destabilization of the model membrane caused by DBBC and DBOP was similar whereas DEBF exerted a weak influence on RBC and BLM stability. The results indicate that the physiological activities of DBOP and DEBF are not limited to the lipid phase of biological membranes and may involve also disturbance of metabolic processes.