Chemical composition and bioactivity of Citrus medica L. cv. Diamante essential oil obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction

The chemical composition of the essential oil of Citrus medica L. cv. Diamante peel obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction techniques was determined by GC/MS analysis. Forty-six components were fully characterised. Limonene and -terpinene were the major components of the oils obtained by hydrodistillation (HD) and cold-pressing (CP), while citropten was the major constituent in the oil obtained by supercritical carbon dioxide extraction (SFE). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities were evaluated. The essential oil obtained by hydrodistillation exerted the highest inhibitory activity against BChE (IC50 value of 154.6 mu g mL-1) and AChE (IC50 value of 171.3 mu g mL-1). Interestingly, the oil obtained by cold-pressing exhibited aselective inhibitory activity against AChE. The essential oils have also been evaluated for the inhibition of NO production in LPS induced RAW 264.7 macrophages. The oil obtained by hydrodistillation exerted asignificant inhibition of NO production with an IC50 value of 17 mu g mL-1 (IC50 of positive control 53 mu g mL-1).