Separation of bioactives from seabuckthorn seeds by supercritical carbon dioxide extraction methodology through solubility parameter approach

Seabuckthorn (Hippophae rhamnoids L.) seed oil having high nutraceutical, cosmeceutical and therapeutic activity has been extracted from dried seabuckthorn (SBT) seed powder using supercritical carbon dioxide (SC-CO2). The solubility parameter of SBT actives (tocopherols, lycopene and β-carotene), CO2, and entrainer solvents was calculated and validated with experimental results. The free radical scavenging activity of the extract was evaluated in terms of DPPH assay. Theoretically, pressure and temperature had significant effect on extraction of SBT actives. A maximum recovery of 77.2% tocopherol, 75.5% carotene and an EC50 of 49.9 mg/mL (from DPPH assay) was obtained after SC-CO2 extraction at 35 °C, 400 bar and run time of 60 min. Further optimization of the extraction conditions by Box–Behnken design increased the extraction efficiency. Use of 2-propanol as an entrainer at 30% v/w of dried SBT seed powder at optimized conditions showed a recovery of tocopherols and carotenes of 91.1% and 69.6%, respectively, while it showed EC50 of 38.9 mg/mL. The optimized conditions were a temperature of 35 °C, pressure of 305 bar and run time of 90 min.

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► Modeling of SC-CO2 extraction of SBT actives by solubility parameter approach.
► The paper correlated for the first time the extraction efficiency with the antioxidant activity.
► Box–Behnken design could successfully optimize the process variables for extraction.
► Use of entrainer further increased the extraction efficiency.
► Maximum extraction efficiency of tocopherols and carotenes was 91.1% and 69.6%, respectively, while it showed EC50 of 38.9 g/mL.