Antioxidant and antibacterial activities of the essential oils and extracts of Dorema ammoniacum roots and aerial parts

Abstract

Background and objectives<em>: Dorema ammoniacum</em> D. Don (Apiaceae) is a monocarpic plant endemic to central Iran. The gum resin of this species is a known therapeutic agent in Iranian, Indian and Western traditional medicines. The aim of the present study was to investigate essential oil constituents and evaluation of antioxidant and antibacterial activities of the essential oils and extracts of <em>D. ammoniacum </em>aerial parts and roots. Methods: Essential oils were analyzed using GC and GC/MS. The oils together with <em>n</em>-hexane, chloroform, ethyl acetate and methanol extracts of the plant samples were subjected to antioxidant evaluation by DPPH and FRAP assays and antibacterial screening using disk diffusion and micro-well dilution methods. Results: Thirty-four compounds were identified in the aerial parts oil, among them β-himachalene (9.3%) and β-chamigrene (8.7%) were the main constituents. Thirty-five compounds were also characterized in the roots oil, of which β-bisabolene (15.1%) and hexadecanal (13.2%) were the main components. Ethyl acetate extract of the roots showed the highest antioxidant activity in both DPPH (IC₅₀ 21.3 ± 2.7 μg/mL) and FRAP (112.7 ± 8.1 mmol FeSO₄.7H₂O equivalent/g) assays. In antibacterial assay, the ethyl acetate and chloroform extracts of the roots exhibited strong antibacterial activity against <em>Bacillus subtilis</em>, <em>Pseudomonas aeruginosa</em> and <em>Staphylococcus aureus</em>. Essential oils were also found to be active against <em>Shigella dysenteriae</em>. Conclusion: Considerable antioxidant and antibacterial activities of <em>D. ammoniacum</em> make it an appropriate candidate for further studies and identification of its bioactive principles.