unusual reduction on the quinonoid ring of 5-amino-8-hydroxy-1,4-naphthoquinone by Staphylococcus aureus

• Published in: Letters in applied microbiology Vol. 42; no. 4; pp. 381 - 385
• Main Authors: Medina, L.F.C, Stefani, V, Brandelli, A
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-04-2006; Blackwell Publishing Ltd; Blackwell Science
• Subjects: antimicrobial; antimicrobial properties; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; hydroquinone; mass spectrometry; Microbiology; naphthoquinones; Naphthoquinones - metabolism; Oxidation-Reduction; oxygen; oxygen uptake; redox reaction; staphylococci; Staphylococcus aureus; Staphylococcus aureus - metabolism; antimicrobial; Oxygen; Applied microbiology; redox reaction; oxygen uptake; staphylococci; Antimicrobial agent; Uptake; Hydroquinone; Reduction; Bacteria; Micrococcales; Micrococcaceae; Naphthoquinone; Staphylococcus aureus
• ISSN: 0266-8254; 1472-765X; 1365-2673
• DOI: 10.1111/j.1472-765X.2006.01863.x

The objective of this study was to investigate the interactions between 5-amino-8-hydroxy-1,4-naphthoquinone (ANQ) and Staphylococcus aureus. The compound ANQ display antimicrobial activity against S. aureus. During incubation with 50 [mu]g ml[superscript [-]1] of ANQ, an unusual reduction reaction takes place and leads to the isolation of 2,3-dihydro-5-amino-8-hydroxy-1,4-naphthoquinone (ANQ-H₂), fully characterized by means of ¹³C-NMR and ¹H-NMR, plus infrared, UV-visible and mass spectroscopy. Oxygen uptake by S. aureus cells was inhibited by ANQ, but in a significantly minor extent by ANQ-H₂. The ability of S. aureus to reduce the double bond at C2-C3 of the ANQ is a unusual behaviour for biological transformation of naphthoquinones. This uncommon reaction may provide valuable understanding of the S. aureus regarding to the antimicrobial effect and the acquisition of resistance to naphthoquinones.