Antioxidative activity of volatile extracts isolated from Angelica tenuissimae roots, peppermint leaves, pine needles, and sweet flag leaves

Volatile extracts were isolated from dried medicinal plants [Angelica tenuissimae roots (AT, Angelica tenuissima Nakai), peppermint leaves (PL, Mentha arvensis L.), pine needles (PN, Pinus sylvestris L.), and sweet flag leaves (SF, Acorus gramineus Rhizoma)] using steam distillation under reduced pressure, followed by continuous liquid - liquid extraction (DRP - LLE). The extracts were then analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The major volatile constituents of AT, PL, PN, and SF were 3-butylidene-4,5-dihydrophthalide (32 mg/g), menthol (18 mg/g), thunbergol (2.1 mg/g), and c/s-asarone (37 mg/g), respectively. The inhibitory activity (%) of the extracts against hexanal oxidation ranged from 33 to 98% at a level of 50 μg/mL. Among the volatile extracts, PL and PN increased cell viabilities by 10 and 24%, respectively, at a dose of 1 μg/mL, compared to that of H₂O₂-treated brain neuroblastoma cells, SK-N-SH. However, a 20% reduction in the malonaldehyde level, an index for lipid peroxidation, was observed at only 1 μg/mL concentration of PN.