Phytochemistry and Biological Activities of Essential Oils from Satureja calamintha Nepeta

Satureja calamintha nepeta (S. calamintha) has a history of successful use in the treatment of bacterial and fungal diseases. The present study was designed to investigate the chemical composition and antioxidant and antimicrobial activities of essential oils extracted from wild S. calamintha (EOSS) and domesticated S. calamintha (EOSD) for comparison purposes. Hydrodistillation was used to extract the essential oils (EOs), while GC/MS was used for chemical analysis. Antioxidant activity was studied using DPPH and FRAP assays. Antifungal activity was performed against Candida albicans, Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum), while antibacterial activity was tested against clinically resistant bacteria, namely Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Proteus mirabilis. By using ab=n in silico approach, the antioxidant and antimicrobial activities of the main compounds of EOSS and EOSD were also investigated. The yields obtained of EOSS and EOSD were 2.80% and 1.95%, respectively, with a dominance of eucalyptol, pulegone and rotundifolone. Concerning the antioxidant power, the IC50 values recorded by the use of the DPPH assay were in the range of 23.03 ± 4.30 and 24.09 ± 4.38 μg/mL for EOSS and EOSD, respectively, while by using the FRAP assay, the EC₅₀ values were in the range of 55.38 ± 2.16 and 60.72 ± 7.71 μg/mL for EOSS and EOSD, respectively. Importantly, both essential oils of EOSS and EOSD exhibited good antibacterial activity against all studied bacteria; notably, the inhibition zone ranged from 14 ± 0.00 to 48.67 ± 1.15 mm and the MICs ranged from 0.37 ± 0.00 to 5.96 ± 0.00 µg/mL. Similarly, the studied EOs showed important antifungal activities compared to all the studied fungi, wherein the inhibition percentage ranged from 47.33 ± 1.15 to 89.18 ± 0.75%, while the MICs ranged from 0.18 ± 0.00 to 2.98 ± 0.00 µg/mL. The molecular docking results showed that piperitenone and pulegone strongly inhibited human acetylcholinesterase, whereas (+)-Isomenthone and piperitenone strongly inhibited S. aureus nucleoside diphosphate kinase, and E. coli beta-ketoacyl-[acyl carrier protein] synthase, respectively. The outcome of this article suggests that EOs of S. calamintha can be developed as alternative agents to manage drug-resistant phenomena and free radical issues.