Effect of bioclimatic area on the composition and bioactivity of Tunisian Rosmarinus officinalis essential oils.

The chemical composition of eight Tunisian Rosmarinus officinalis L. populations (A-H) from different bioclimatic areas has been examined by gas chromatography (GC) and GC-mass spectrometry. The essential oils are characterised by high amounts of oxygenated monoterpenes (58.2-71.7%) followed by monoterpene hydrocabons (15.1-26.7%). 1,8-Cineole, camphor, α-pinene and borneol are the main representative components. The antioxidant activity was investigated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing ability power assay and β-carotene bleaching test. Samples showed antiradical activity by inhibiting DPPH radical with IC50 values ranging from 375.3 to 592.8 μg mL(- 1) for samples F and A, respectively. Sample A also showed the most promising activity in β-carotene bleaching test (IC50 of 31.9 μg mL(- 1)). The essential oils were also screened for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity. Sample G showed the highest activity against AChE (IC50 of 64.7 μg mL(- 1)) while sample D (IC50 of 29.5 μg mL(- 1)) exhibited the most potent activity against BChE.