Antioxidant potential and chemical composition of essential oils from Mentha longifolia, Lavandula angustifolia, and Ocimum basilicum grown in the Oued Souf region, Algeria

This study examined the antioxidant potential of essential oils (EOs) from Mentha longifolia (MEo), Lavandula angustifolia (LEo), and Ocimum basilicum (BEo) cultivated in Algeria’s arid Oued Souf region. GC-MS analysis highlighted unique chemical compositions, with LEo rich in linalool (21.37%) and linalyl acetate (30.92%), BEo high in phenylpropanoids (37.25%), especially estragole (20.65%) and linalool (30.17%), and MEo dominated by cis-isopulegone (59.68%). Antioxidant activity was evaluated via FRAP, DPPH, and TCA assays. BEo showed the highest FRAP activity (EC \(_{50}\) $_{50}^{}$ = 2.96 ± 0.05 \(\mu\) $\mu$ g/mL), followed by LEo and MEo (EC \(_{50}\) $_{50}^{}$ = 5.08 ± 0.2 \(\mu\) $\mu$ g/mL and 5.89 ± 0.1 \(\mu\) $\mu$ g/mL, respectively). In the DPPH assay, BEo also exhibited the strongest radical-scavenging activity (IC \(_{50}\) $_{50}^{}$ = 0.053 ± 0.45 mg/mL) compared to LEo (IC \(_{50}\) $_{50}^{}$ = 25.55 ± 0.29 mg/mL) and MEo (IC \(_{50}\) $_{50}^{}$ = 16.89 ± 0.023 mg/mL). Similarly, BEo displayed the greatest inhibition in the TCA assay (EC \(_{50}\) $_{50}^{}$ = 3.5 ± 0.16 mg/mL). These findings underscore BEo’s remarkable antioxidant capacity, potentially linked to its rich phenylpropanoid profile, suggesting that environmental stressors in arid regions enhance the bioactive compound concentrations in essential oils. This structural resilience may make these oils powerful natural alternatives to synthetic antioxidants, offering promising applications for managing oxidative stress.