Influence of rosmarinic acid on opsonization and intracellular killing ofEschericha coli andStaphylococcus aureus by porcine and human polymorphonuclear leucocytes

Abstract
The influence of rosmarinic acid on the function of porcine and human polymorphonuclear leucocytes was tested. Rosmarinic acid inhibited the chemiluminescence of PMNL, induced by preopsonized Zymosan or phorbol myristate acetate. The killing ofEscherichia coli was inhibited by rosmarinic acid at a concentration of 2 mM, but not that ofStaphylococcus aureus. The inhibition of the killing was due to an impaired opsonization, caused by an adverse influence of rosmarinic acid on complement activation. Direct effects of rosmarinic acid on the killing mechanisms of PMNL were not observed.