Comparison of the Volatile Constituents of Elsholtzia fruiticosa Extracted by Hydrodistillation, Supercritical Fluid Extraction and Head Space Analysis

Volatile constituents of Elsholtzia fruiticosa (D. Don) Rehder were studied by two different extraction techniques, supercritical fluid extraction (SFE) and hydrodistillation (HD), and the results were compared with head space analysis (HS). Thirty-five constituents were identified in both the SFE and HD oils and fourteen in the HS, accounting for 94.2%, 97.7% and 96.9% of the total identifications, respectively. A distinctive feature of the results was the very high content of non-terpenes (59.8%) in the HS, the high content of oxygenated monoterpenes (41.1%) in the HD oil and the high content of sesquiterpene hydrocarbons (21.8%) in the SFE oil. Monoterpene hydrocarbons were represented in HS (13.6%), HD (19.4%) and SFE (4.3%). In SFE sesquiterpene hydrocarbons formed 21.8% of the total, as compared to 6.6% in the HD and 1.1% in the HS Oxygenated sesquiterpenes represented 3.0% in SFE, 0.8% in HD and were absent in HS. Diterpenes were only present in the SFE oil (3.4%). Non-terpenes were represented by 24.5% in the SFE oil and 29.8% in the HD oil.