Essential Oils of Ginkgo biloba Yellow Leaves Obtained by Hydrodistillation and Supercritical Carbon Dioxide Extraction

Abstract

Background/Objective: Volatile compounds present in green Ginkgo biloba L. leaves extracts contain compounds that can undertake free radical scavenging. The assumption was that volatile compounds present in yellow Ginkgo biloba leaves extracts have a different composition compared to green Ginkgo biloba leaves extracts. The investigation was conducted in order to determine the compounds in yellow Ginkgo biloba leaves’ extracts that can undertake free radical scavenging. Methods: The volatile compounds present in yellow Ginkgo biloba leaf extracts were obtained by hydrodistillation and supercritical carbon dioxide (CO2) extraction. The obtained essential oils were analyzed by gas chromatography–mass spectrometry. Results: The essential oil obtained by hydrodistillation consisted of monoterpenes (3.1%), oxygenated monoterpenes (15.3%), sesquiterpenes (6.2%), oxygenated sesquiterpenes (51.4%), esters (1.3%), benzopyrans (7.1%), an oxolane (1.5%), and a rose ketone (0.8%). Caryophylene-4(12),8(13)-dien-5α-ol (7.1%) was the most abundant compound, followed by 14-hydroxy-( Z)-caryophyllene (5.8%), caryophyllene oxide (5.8%), and hydroxydihydroedulan (5.6%). The supercritical fluid extraction was done under the pressure of 30 MPa, at the temperature of 40 °C and the CO2 flow rate was 2 kg·h−1. The obtained chromatogram revealed the presence of 12 compounds. The main constituents were squalene (110.5 mg per 100 g of plant material) and α-tocopherol (99.3 mg per 100 g of plant material). Conclusion: The well-known compound that has a free radical scavenging activity α-tocopherol was determined in yellow Ginkgo biloba leaves extract obtained by supercritical CO2 extraction.