Combined Analysis by GC (RI),GC-MS and 13 C NMR of the Supercritical Fluid Extract of Abies alba Twigs

Abstract

Two samples (leaves and twigs) of Abies alba Miller from Corsica were extracted using supercritical CO₂ and their chemical compositions were compared with those of the essential oils obtained from the same batch of plant material. In total 45 components were identified using combined analysis by GC (RI), GC-MS and ¹³C NMR. It was observed that the contents of monoterpenes (mainly represented by limonene, α-pinene and camphene) were significantly lower in the supercritical fluid extract (SFE) than in the essential oil (EO). Conversely, the proportions of sesquiterpenes were much higher in CO₂ extracts than in essential oils (around 30% vs 4%). Cis-abienol, a diterpene alcohol, was identified only in SFE, and the proportions of this constituent (7.5% and 17.3%) were determined using quantitative ¹³C NMR since it was under estimated using the standard conditions of GC.