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Calamintha officinalis Moench essential oil is used in cooking as an aromatic herb and also to improve the flavor and fragrance of several pharmaceutical products. The essential oil, obtained by hydrodistillation (5 mL/kg), was analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection. Sixty-four components were identified, constituting 99.7% of the total oil. The major component was found to be carvone (38.7%), followed by neo-dihydrocarveol (9.9%), dihydrocarveol acetate (7.6%), dihydrocarveol (6.9%), 1,8 cineole (6.4%), cis-carvyl acetate (6.1%), and pulegone (4.1%). The essential oil showed antifungal and antimicrobial activity against Gram-positive bacteria. In addition, it presented a very low toxicity both in vivo (50% lethal dose >100 mg/kg) and in vitro in the Artemia salina test (50% lethal concentration >500 μL/mL). C. officinalis essential oil, in rodents, produces the typical effects in behavior of a nonselective central nervous system-depressant drug; it potentiates the hypnotic effects of sodium pentobarbital, decreasing the induction time and enhancing the sleeping time. Moreover, it produces a decrease in body temperature and a protection against pentylenetetrazole-induced convulsions.

Carvacrol is an antimicrobial monoterpenic phenol which occurs in many plant essential oils. The aim of this study was to investigate its activity at acidic pH on staphylococcal forming and yet established biofilms, with particular focus to improve its effectiveness on Staphylococcus epidermidis biofilm. The results showed that the subinhibitory doses (1/2, 1/4 and 1/8 MIC) of carvacrol determined a higher reduction of S. epidermidis biofilm formation than that observed at neutral pH. A potentiated inhibitory effect was also observed on established biofilm, carvacrol caused either a strong reduction of biomass (>50%) and bacteria attached to polystyrene (>7 log units). The images of scanning electron microscopy and the gas‐chromatographic analysis support these results. The development of acidic formulations containing carvacrol could be an important tool to control the staphylococcal biofilm in the medical and food environment.

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