FARMACIA, 2014, Vol. 62, 6 1214 INTERACTIONS BETWEEN CARDAMOM ESSENTIAL OIL AND CONVENTIONAL ANTIBIOTICS AGAINST STAPHYLOCOCCUS AUREUS CLINICAL ISOLATES ADINA CATINCA GRĂDINARU 1 , ANA CLARA APROTOSOAIE 1* , ADRIANA TRIFAN 1 , ADRIAN ȘPAC 1 , MIHAI BREBU 2 , ANCA MIRON 1 1 Faculty of Farmacy, Grigore T.Popa University of Medicine and Pharmacy Iasi, 16 Universitatii Street, Romania, Iași, 700115 2 Physical Chemistry of Polymers Laboratory, “Petru Poni” Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41A, Romania, Iași, 70048 *corresponding author: anaclara70@yahoo.com Abstract The aim of this study was to investigate the effects of cardamom essential oil and antibiotics combinations against methicillin-resistant clinical isolates and ATCC 25923 reference strain of Staphylococcus aureus. The interaction of the essential oil with the antibiotics was assessed by the checkerboard method. The chemical composition of essential oil was analysed by gas chromatography with mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID) and α-terpinyl acetate (39.59%) and 1,8-cineole (31.27%) were identified as main compounds. Combinations of cardamom essential oil with amoxicillin or ciprofloxacin exerted mainly additive and indifferent effects on methicillin-resistant clinical isolates while combinations of 1,8-cineol with antibiotics generated antagonistic and indifferent effects. Additive effects on Staphylococcus aureus ATCC 25923 were generated by the following combinations: cardamom essential oil – ciprofloxacin, 1,8-cineol – amoxicillin and 1,8-cineol – ciprofloxacin. The antagonistic interactions noted here, particularly for 1,8-cineol, suggest that its concomitant administration with amoxicillin or ciprofloxacin, depending on the combination ratios, can diminish the antibacterial activity of these antibiotics in infections with Staphyloccocus aureus isolates. Rezumat Acest studiu a avut drept obiectiv investigarea efectelor combinațiilor între uleiul volatil de cardamom și antibiotice asupra unor izolate clinice meticilin-rezistente și tulpinii standard ATCC 25923 a patogenului Staphylococcus aureus. Interacțiunea uleiului volatil cu antibiotice a fost evaluată prin metoda checkerboard. Compoziția chimică a uleiului volatil a fost analizată prin GC-MS și GC-FID, iar acetatul de α-terpinil (39,59%) și 1,8- cineolul (31,27%) au fost identificați drept constituenţi majoritari. Combinațiile uleiului volatil de cardamom cu amoxicilina sau ciprofloxacina au exercitat, in principal, efecte aditive și indiferente asupra izolatelor clinice meticilin-rezistente de stafilococ auriu în timp ce combinațiile 1,8-cineolului cu antibiotice au generat efecte antagonice și indiferente. Următoarele combinații: ulei volatil de cardamom-ciprofloxacina; 1,8-cineol-amoxicilina și