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-octylamin o-2-propanephosphonate (DBOP) on the growth of the aquatic plant Spirodela oligorrhiza and stability of red blood cells (RBC) and planar lipid membran es (BLM) was studied to determine its physiological activity and, if possib le correlate this activity to compound-induced changes in the mechanical pr operties of thr model membranes, The measure of the phytotoxicity was the D BOP concentration causing 50 % plans growth retardation, while measures of stability of model membranes were 100 % hemolysis of RBC and a critical con centration 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 ibr the ir physiological activities Both DBBC and DEBF influenced Spirodela growth significantly less than DBOP Destabilization of the model membrane caused b y DBBC and DBOP was similar whereas DEBT exerted a weak influence on RDC an d DLM stability. The results indicate that the physiological activities of DBOP and DEDI: are not limited to the lipid phase of biological membranes a nd may involve also disturbance of metabolic processes.