AN IN-VITRO SYSTEM SIMULATES IN MEMBRANES THE ANTIBACTERIAL MECHANISMPOSTULATED FOR THE ACTION OF ISOXAZOLYLNAPHTHOQUINONEIMINE IN STAPHYLOCOCCUS-AUREUS

The -dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (Q(1)) revealed good activity against Staphylococcus aureus. Q(1) in contact with the bacteria experimented reduction evidenced by changes in its spectrum of absorption simultaneously with loss of colour. During the first 4 h ours of incubation, oxygenation restored the original spectrum. Treatm ent with sodium borohydrure reduces irreversibly Q(1). Redox-reaction ''in vitro'' was detected between Q(1) and NADH in the presence of dia phorase. The environment of the probable site of action of Q(1) was si mulated using an artificial membrane system, instead of S. aureus memb ranes. Q(1) interacts with lisophosphatidylcholine micelles following a cooperative binding model. The kinetics of Q(1)-reduction was increa sed by lipid micelles incorporated with the antibacterial compound. (C ) 1997 Academic Press.