RIFAMYCINS INHIBIT HUMAN NEUTROPHIL FUNCTIONS - NEW DERIVATIVES WITH POTENTIAL ANTIINFLAMMATORY ACTIVITY

In our study we investigated the effect of rifamycin SV, rifamycin B, rifampicin and five semisynthetic derivatives on human neutrophil func tions such as locomotion, superoxide production and degranulation stim ulated by specific agonists. All compounds were tested at concentratio ns ranging from 10(-9) to 10(-5) M. Among the newly synthesized compou nds the most active we found to be the derivatives carrying an acidic substituent at C3: these significantly lowered the superoxide generati on induced by PMA throughout the entire concentration range, whereas r ifamycin SV, rifamycin B and rifampicin were effective only at the hig hest concentrations. Moreover, chemotactic movement was significantly attenuated by derivative R4, rifamycin B and rifamycin SV at high dose s; granule enzyme release was unaffected by all compounds.