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The chemical composition of Trachyspermum ammi essential oil (EO) was analyzed by gas chromatography–mass spectrometry, and thymol (63.4%), p‐cymene (19%) and γ‐terpinene (16.9%) were found as the major components. The antimicrobial properties of the EO were investigated against 10 important foodborne pathogenic bacteria and spoilage fungi by disk diffusion and by determining the minimum inhibitory concentration (MIC). The EO exhibited strong activity against both bacteria and fungi, with greater inhibition of bacterial growth compared with fungi; MIC value of EO against all bacteria was evaluated at 500 ppm, whereas the fungal species were inhibited at concentrations of 1000–2000 ppm. The EO also showed antioxidant activity assessed by 2,2‐diphenyl‐1‐picrylhydrazyl, with IC50 (concentration providing 50% inhibition) of 34 μg/mL. Similarly, in β‐carotene/linoleic acid assay, the EO was effectively able to inhibit the linoleic acid oxidation, exhibiting 82.16% inhibition that was similar to butylated hydroxytoluene. Overall, the EO exhibit potent antimicrobial and antioxidant activity, which supports its potential use for perishable and high fatty foods. Practical Applications This study is the first report of the chemical composition of Iranian Trachyspermum ammi essential oil and its antimicrobial and antioxidant activities. In conclusion, the obtained data indicate that the essential oil exhibits potent antibacterial and antifungal activity, which supports its use in traditional medicine for its antiseptic properties. The results clearly show that the oil of T. ammi presents antioxidant activity and might be useful for high fatty foods.

Bromophenols are known as antioxidant radical scavengers for some biomolecules such as those in marine red alga. Full understanding of the role played by bromophenols requires detailed knowledge of the radical scavenging activities in probable pathways, a focus of ongoing research. To gain detailed insight into two suggested pathways, H-atom transfer and electron transfer, theoretical studies employing first principle quantum mechanical calculations have been carried out on selected bromophenols. Detailed investigation of the aforementioned routes revealed that upon H-atom abstraction or the electron transfer process, bromophenols cause an increase in radical species in which the unpaired electron appears to be delocalized as much as possible over the whole aromatic ring, especially in the bromine substituent. The O-H bond dissociation energies (BDEs) and ionization potential energies (IPs) are reported at the B3LYP level of theory, providing the first complete series of BDEs and IPs for bromophenols. The observations are compared to those of other antioxidants for which BDEs and IPs have been previously obtained.

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