Essential Oil Compositions, Antioxidant and Antibacterial Activities of Two Salvia Species (S. grossheimii Bioss. and S. syriaca L.) Growing in Iran

Abstract

Free radicals and microorganisms are reason of a number of diseases. Plant secondary metabolites may have important role in the prevention of these diseases. Lamiaceae family is potential sources of secondary metabolites that may function as natural antioxidants and antibacterial. The aim of this study is in vitro assessment of total phenol and flavonoid contents and antioxidant activities of the methanolic extracts of two Salvia species, namely S. syriaca and S. grossheimii. In addition, aerial parts of the species were hydrodistilled in a Clevenger-type apparatus and analyzed by GC-MS. Finally, methanolic extracts and essential oils of both species were evaluated for their antibacterial activities. Total phenol and flavonoid contents were measured by Folin-Ciocalteu and AlCl assays. Antioxidant activity of the extracts was screened by four complementary test systems, namely DPPH free radical-scavenging, metal chelating activity, anion superoxide radicals scavenging and β-carotene/linoleic acid model system. The antibacterial activity was studied by agar disc diffusion method. Both Salvia species studied were not significantly different in total phenol content. Our results indicated that the Salvia metanolic extracts have effective antioxidant functions. Totally, 40 compounds were characterized in the essential oil of S. grossheimii with germacrene D (12.4 %), α-pinene (11.6 %) and β- pinene (9.5 %) as dominant components and 22 compounds were identified in the essential oil of S. syriaca, with (+) spathulenol (20.5 %), borneol (17.9 %), bicyclogermacrene (11.1 %) and germacrene D (10.7 %) as the major constituents. Both species showed antibacterial activity against the most of bacterial strains tested. Both of Salvia species showed strong antioxidant and antibacterial activities. Then, they may be new health- care foods and drug supplements for special use in the future.