Cytotoxic and Antioxidant Properties of Natural Bioactive Monoterpenes Nerol, Estragole, and 3,7-Dimethyl-1-Octanol.

The therapeutic potential of medicinal plants is noted because of the presence of varieties of biochemicals. The monoterpenes, like nerol, estragole, and 3,7-dimethyl-1-octanol, have been reported for antimicrobial, antifungal, anthelmintic, and antioxidant activities. This study evaluated the toxic, cytotoxic, and oxidant/antioxidant effects of these compounds by several in vitro (DPPH and ABTS radical scavenging, and ferric reducing potential), ex vivo (hemolysis), and in vivo (Artemia Salina and Saccharomyces cerevisiae) assays. Results suggest that estragole and 3,7-dimethyl-1-octanol at 31.25-500 µg/mL did not exhibit significant cytotoxic effects in the A. Salina and hemolysis tests. Nerol showed significant cytotoxic effects on these test systems at all test concentrations. The monoterpenes showed radical (ABTS•+ and DPPH•) scavenging capacities in a concentration-dependent manner in vitro tests. However, they did not oxidize the genetic material of S. cerevisiae (SODWT, Sod1Δ, Sod2Δ, Sod1/Sod2Δ, Cat1Δ, and Cat1Δ/Sod1Δ) lines. Among the three monoterpenes, nerol may be a good candidate for antioxidant and anti-tumor therapies.

Rejection of hemolyzed samples can jeopardize patient safety.

INTRODUCTION: In vitro hemolysis is the primary cause of sample/test rejection by the laboratory. CASE REPORT: A 10-year-old, admitted with an asthma attack in the emergency-room, medicated with albuterol sulphate (intravenous bronchodilator that could induce hypokalemia), needed laboratory test monitoring. The physician prescribed the technical-nurse to perform blood sampling for: complete blood count, electrolytes, glucose, and blood gas analysis-within 30min after therapy. Samples were delivered to laboratory with a note "I had difficult to locate an appropriate access to perform the blood collection". LABORATORY RESULTS: Glucose: 4.77 mmol/L. Complete blood count revealed discreet eosinophilia 0.13x109/L, and thrombocytopenia 18x109/L. However, platelet clumps were observed in peripheral blood smear. Blood gas analysis was unreported, laboratory informed that sample had micro clots.Electrolytes: laboratory did not report the results; sample hemolyzed. 0.9 g/L of free hemoglobin is the cut-off defined by the laboratory; the sample presented 2.3 g/L of free hemoglobin. 3.9 mmol/L of potassium was the unreported result vs 2.1 mmol/L in the new sample.Briefly, the laboratory technician was trained to hide potassium results on hemolyzed sample due to the potential overestimation. Even if the hemolyzed sample presented a potassium value close to the lower reference range value (3.5-5.1 mmol/L), reporting the potassium result could allow the physician starting proper therapy to revert the hypokalemia by albuterol sulfate. CONCLUSION: The laboratory should be aware of the clinical patient conditions and of the related physician needs, before hiding results. Therefore, both the laboratory and the clinic personnel should communicate in order to guarantee the patient safety.

Inhibition of the NorA multi-drug transporter by oxygenated monoterpenes.

The aim of this study was to investigate intrinsic antimicrobial activity of three monoterpenes nerol, dimethyl octanol and estragole, against bacteria and yeast strains, as well as, investigate if these compounds are able to inhibit the NorA efflux pump related to fluoroquinolone resistance in Staphylococcus aureus. Minimal inhibitory concentrations (MICs) of the monoterpenes against Staphylococcus aureus, Escherichia coli and Candida albicans strains were determined by micro-dilution assay. MICs of the norfloxacin against a S. aureus strain overexpressing the NorA protein were determined in the absence or in the presence of the monoterpenes at subinhibitory concentrations, aiming to verify the ability of this compounds act as efflux pump inhibitors. The monoterpenes were inactive against S. aureus however the nerol was active against E. coli and C. albicans. The addition of the compounds to growth media at sub-inhibitory concentrations enhanced the activity of norfloxacin against S. aureus SA1199-B. This result shows that bioactives tested, especially the nerol, are able to inhibit NorA efflux pump indicating a potential use as adjuvants of norfloxacin for therapy of infections caused by multi-drug resistant S. aureus strains.