Essential oil and total flavonoids extracted from Torreya grandis cv. Merrilli arils using SFE with/without co-solvent: Process optimization, chemical composition, and biological activities

This study systematically evaluated the continuous supercritical CO 2 fluid extraction (SFE-CO 2 ) process, chemical composition, and biological activities of low and high-polar bioactive components extracted from Torreya grandis cv. Merrilli arils. The optimal SFE-CO 2 conditions for the extraction of essential oil (EO) and total flavonoids (TFs) were determined as follows: 28.84 MPa pressure, 40.65°C temperature, 4.99 h extraction time, and a predicted inhibitory zone diameter (IZD) of 31.49 cm for EO; and 32 MPa pressure, 45.83℃ temperature, 3.16 h extraction time, 41.23% co-solvent ratio (ethanol/methanol, v/v), and a predicted antioxidant activity of 79.67% for TFs. Comprehensive GC-MS analysis identified a total of 195 components in EO, among which terpenoids comprising the highest relative content at 58.18%. Monoterpenoids and sesquiterpenoids accounted for 52.67% (57 compounds) and 46.43% (44 compounds), respectively. Notably, δ-3-carene, (+)-δ-cadinene, and β-pinene displayed relative abundances of 15.20%, 9.97%, and 9.86%. EO demonstrated pronounced inhibitory effect against Staphylococcus aureus , with a minimal inhibitory concentration (MIC) of 0.32 mg/mL. Mechanism studies indicated that EO disrupted cell wall and membrane integrity, as evidenced by the leakage of intracellular nucleic acids, proteins, electrolytes and alkaline phosphatase (AKP) from S. aureus cells. TFs exhibited notable radical-scavenging capacity and phytotoxicity on seeds germination and seedlings growth of Digitaria sanguinalis , Poa annua and Avena fatua , which were positively correlated with reduced antioxidant enzymes activities and increased malondialdehyde (MDA) accumulation. These findings highlight the potential application of bioactive components derived from T. grandis cv. Merrilli arils across multiple fields. Furthermore, this approach supports the efficient utilization of agricultural waste, mitigates ecological and environmental pollution, and enhances the economic and practical value of T. grandis cv. Merrilli .