Free Radical Scavenging Principles of Salvia reuterana Boiss. Aerial Parts

Salvia reuterana Boiss. is an aromatic perennial plant traditionally used for its anxiolytic and sedative properties. In the present study, various fractions and essential oil of S. reuterana aerial parts were investigated to find its free radical scavenging principles. Hydroalcoholic fraction with IC(50) value of 112.6 ±3.2 μg mL(-1) in DPPH assay demonstrated the highest free radical scavenging activity and was selected to further phytochemical investigation. RP-18 and Sephadex LH-20 column chromatography of the hydroalcoholic fraction resulted in the isolation and structural elucidation of four phenolic derivatives, including apigenin-7-O-β-D-glucopyranoside (1), luteolin-7-O-β-D-glucopyranoside (2), rosmarinic acid (3), and luteolin (4). Isolated compounds showed potent free radical scavenging activities (5.1-34.2 μg mL(-1)), compared with BHT (21.30 ± 1.9 μg mL(-1)). Twenty four compounds were also identified in GC-MS analysis of the plant essential oil, of which benzyl benzoate (26.64%), n-hexyl benzoate (22.99%) and n-hexyl isovalerate (6.04%) were the main compounds. The results of the present study introduced S. reuterana as a valuable source of natural phenolic antioxidants which can be utilized in prevention of oxidative stress related diseases. Moreover, interesting composition of S. reuterana essential oil, dominated by non-terpenes compounds (76.17%) especially aromatic derivatives, make it an appropriate candidate for more detailed studies.