Comparison of headspace analysis of volatile constituents with GCMS analysis of hydrodistilled and supercritical fluid extracted oil of Capillipedium parviflorum

Abstract

Volatile constituents of the aerial parts of Capillipedium parviflorum were studied by two different extraction procedures, hydrodistillation (HD), supercritical CO2 extraction (Sc-CO2) and compared with headspace analysis (HS). Sc-CO2 extraction was carried out using nine differential optimization extractions (DOX) at different temperatures (°C) and pressures (MPa), i.e. 35/9, 60/9, 85/9, 35/17, 60/17, 85/17, 35/25, 60/25 and 85/25, to assess the influence on the yield and composition of volatile constituents. In DOX experiments, oil yields varied between 0.01–0.18% and maximum yield (0.18%) was obtained using temperatures and pressures 35/17 and 85/25. The oil is characterized by distinctive presence of very high content of non-terpenes (90.7%) identified in HD oil, 84.0% in Sc-CO2 oil and 92.5% in HS analysis. Monoterpenes were represented in low concentrations in HD oil and were totally absent in Sc-CO2 as well as in HS analysis. Very little variability was observed in the oxygenated monoterpenes in both Sc-CO2 and HD oil representing a low percentage of constituents. Sesquiterpene hydrocarbons were represented between 1.5% and 3.1% in Sc-CO2 extraction, which was higher in comparison with HD and HS techniques. Oxygenated sesquiterpenes were represented in higher percentage in Sc-CO2 than in HD oil and HS analysis. Variability among the major constituents of 4-nonanone, 4-nonanol, 4-undecanone and 4-undecanol was observed in Sc-CO2 extraction carried out under varied temperatures and pressures. Their percentage also varied in HD and HS analysis. 4-Nonanone (2.5%, 60/9 in Sc-CO2; 6.4% in HD and 4.3% in HS), 4-nonanol (21.5% in Sc-CO2, 31.7% in HD and 29.5% in HS), 4-undecanone (33.3%, 85/9 in Sc-CO2; 35.3% in HD and 44.5% in HS) and 4-undecanol (16.5%, 84/17, 60/25 in Sc-CO2; 14.6% in HD and 10.3% in HS) dominated the volatile constituents.