Shikonin Inhibited Growth and N-acetylation of 2-aminofluorene in Bacteria Strains Staphylococcus aureus and Klebsiella pneumoniae

Abstract

Objectives. N-acetyltransferase (NAT) is the first step in the metabolism (N-acetylation) of arylamine carcinogens (2-aminofluorene) and drugs (sulfamethazine). Angiogenesis is critical for tumor growth and inflammation, and shikonin has been reported to inhibit angiogenesis and induce apoptosis in vivo and in vitro. Therefore, our objective was to investigate the effect shikonin has on growth and N-acetylation of 2-aminofluorene in bacteria. Methods. In this study, growth inhibition of S. aureus and K. pneumoniae was determined by measuring absorbance by an optical density method (OD at 650 nm) using a Beckman Spectrophotometer (DU 6401). We examined arylamine N-acetyltransferase (NAT) activity in the bacteria S. aureus and K. pneu1I1oniae collected from patients and examined the levels of Nacetylation of 2-aminofluorene by high performance liquid chromatography. Results. Shikonin elicited dose-dependent bacteriostatic activity in both examined bacteria cultures. Cytosols and suspensions of S. aureus and K. pneumoniae with and without specific concentrations of shikonin co-treatment showed different percentages of 2-aminofluorene acetylation. The data indicated that the decrease in N-acetylation of 2-aminofluorene was associated with increased levels of shikonin in both examined bacteria cytosols and intact cells. The apparent values of Km and Vmax decreased after co-treatment with 4 μM shikonin. Conclusions. Shikonin induces inhibition of growth and inhibition of arylamine NAT activity (N-acetylation of 2-aminofluorene) in S. aureus and K. pneumoniae.