Chemical composition and antioxidant activity of volatiles from Patrinia Villosa Juss obtained by optimized supercritical fluid extraction

Supercritical CO2 fluid extraction (SFE-CO2) was used to extract volatiles from Patrinia Villosa Juss. An orthogonal test L9 (3)4 including pressure, temperature, dynamic extraction time and modifier was performed to get the optimal conditions. Extract 1 was obtained by the optimal extraction condition 1: pressure = 35 MPa, T = 45 °C, dynamic extraction time = 2.0 h and Vmodifier (MeOH) = 0% as guided by the index 1: the free radical scavenging activities in vitro against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) diammonium salt (ABTS). Extract 2 obtained by the optimal extraction condition 2: pressure = 25 MPa, T = 55 °C, dynamic time = 2.5 h and Vmodifier (MeOH) = 20% was guided by the index 2: the yield of the volatiles. The results showed that extract 1 possessed stronger antioxidant activity (EC50 = 32.01 μg/ml to DPPH and 50.90 μg/ml to ABTS+) than the extract 2 (EC50 = 95.62 μg/ml to DPPH and 99.78 μg/ml to ABTS+). Subsequently, the chemical compositions of the two extracts were identified by gas chromatography-mass spectrometry. Forty-six compounds were identified from extract 1, and the total volatile consisted of hydrocarbon (49.65%), aldehyde (16.66%), fatty acid (22.38%), terpene (9.04%) and little alcoholic. From extract 2, 32 compounds were identified, in which hydrocarbon, aldehyde, fatty acid and terpene possessed 58.21%, 5.97%, 13.19% and 21.79%, respectively. This is the first report of using SFE to extract the volatiles from P. Villosa Juss (a wild vegetable and medicine plant) and first time to systematically evaluate the volatiles' antioxidant activity and chemical composition.