Chemical composition of Torreya grandis essential oils and enantiomeric analysis of key monoterpenes

This study chemically characterized three Torreya grandis ( T. grandis ) essential oil samples provided by Zhengmao Ecological Agriculture Development Co. (Hubei, China), obtained through their standardized steam distillation of: (1) fresh arils, (2) dried arils, and (3) combined leaves/twigs. GC–MS analysis identified 107 terpenoid compounds, with limonene (210.96–328.05 mg/mL) and α -pinene (131.30–237.40 mg/mL) as dominant constituents. Five secondary components ( β -pinene, 3-carene, β -myrcene, terpinolene, δ -cadinene) consistently occurred at 10–100 mg/mL. Chiral resolution demonstrated enantiomeric specificity: (−)- α -pinene showed tissue-dependent enrichment (78 % ee in arils vs. 29 % in leaves/twigs), whereas ( R )-(+)-limonene maintained near-enantiopurity (∼96 % ee) across all samples. Isolation and optical rotation analysis confirmed (+)-torreyol in leaf/twig oils. Bioactivity assessments revealed concentration-dependent antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging up to 89 % at 100 mg/mL) and selective antibacterial effects, with aril oils exhibiting strong inhibition against Staphylococcus aureus ( S. aureus ) (30.16 mm zone) but limited activity against Escherichia coli ( E. coli ), though less potent than BHT (IC 50 40.73–64.77 mg/mL vs. 94 μg/mL). The distinct enantiomeric patterns and abundant bioactive terpenoids highlight T. grandis essential oils as sustainable, high-value ingredients for flavor/fragrance industries, motivating further research into their biosynthetic regulation and commercial optimization.