Formulation of a Three-Component Essential Oil Mixture from Lavandula dentata, Rosmarinus officinalis, and Myrtus communis for Improved Antioxidant Activity

The optimization of existing natural antioxidants that are highly effective is crucial for advancements in medicine and the food industry. Due to growing concerns regarding the safety of synthetic antioxidants, researchers are increasingly focusing on natural sources, particularly essential oils (EOs). Combining EOs might enhance antioxidant activity due to increased chemical diversity. This study investigates, for the first time, the antioxidant properties of EOs from <i>Lavandula dentata</i>, <i>Rosmarinus officinalis</i>, and <i>Myrtus communis</i>, both individually and in combination, using the augmented-simplex design methodology. The in vitro evaluation of the antioxidant activity was performed using DPPH and ABTS radical scavenging assays. Chromatography gas-mass spectrometry (CG-MS) revealed that 1,8-cineol (37.27%) and pinocarveol (12.67%) are the primary components of <i>L. dentata</i>; verbenone (16.90%), camphor (15.00%), and camphene (11.03%) are predominant in <i>R. officinalis</i>; while cineol (43.32%) is the main component of M. communis. The EOs showed varying scavenging activities against ABTS and DPPH radicals, with DPPH assay values ranging from 194.10 ± 3.01 to 541.19 ± 3.72 µg/mL and ABTS assay values ranging from 134.07 ± 1.70 to 663.42 ± 2.99 µg/mL. These activities were enhanced when the EOs were combined. The optimal antioxidant blend for DPPH_IC50 consisted of 20% <i>L. dentata</i>, 50% <i>R. officinalis</i>, and 30% <i>M. communis</i>. For the highest ABTS radical scavenging activity, the best combination was 18% <i>L. dentata</i>, 43% <i>R. officinalis</i>, and 40% <i>M. communis</i>. These results highlight the potential of EO combinations as new natural formulations for use in cosmeceutical, food, and pharmaceutical sectors.