Selectivity of supercritical CO2 extraction and atmospheric pressure techniques for the major volatile compounds of Eugenia involucrata leaves from Southern Brazil

Abstract

The essential oil and bioactive compounds of Eugenia involucrata leaves from Southern Brazil were extracted using supercritical CO2 extraction (SFE), Soxhlet and hydrodistillation (HD). The extracts’ volatile compounds were identified and the antioxidant activity was measured for comparison. The SFE extraction curve and the time-dependent volatile compounds compositions were also evaluated. The essential oil obtained by HD presented a high content of sesquiterpenes, mainly β-elemene (BE) and bicyclogermacrene (BG). The extracts obtained by SFE at 200bar and 40°C exhibited a similar BE content and a higher selectivity for BG. These components were also present in a lower relative amount in the Soxhlet extracts. Chemical analysis of the SFE extracts collected at 50–80min of processing time showed 62% of BE and 38% of BG for the volatile fraction, representing 100% of major compounds content. The highest antioxidant activity was detected in the Soxhlet extracts (99%), followed by the supercritical products (94%) and, finally, the essential oil (6%). Thereby, the SFE products present enhanced characteristics since they combine the main positive aspects of each conventional technique. Furthermore, they are solvent-free and preserve the original organoleptic properties of the matrix components, which is a well desired feature in pharmaceutical, cosmetic and food applications.