Chemical composition and antimicrobial activity of Rosmarinus officinalis L. oils from Sardinia and Corsica

A detailed analysis of Rosmarinus officinalis L. essential oil from Sardinia and Corsica (α‐pinene/verbenone/bornyl acetate chemotype) was carried out using GC–RI, GC–MS and 13 C‐NMR, on the bulk sample or after repeated chromatography. Fifty‐eight compounds were identified. The antimicrobial activity of two Sardinian samples was investigated and both exhibited a moderate antibacterial activity. Gram‐positive bacteria were more sensitive (MIC 2.5–4 mg/ml) than Gram‐negative bacteria. Killing time experiments demonstrated that prolonged times (60 min) are needed to completely inactivate the bacterial inoculum.