The development of novel antioxidant compounds with high efficacy and low toxicity is of utmost importance in the medicine and food industries. Moreover, with increasing concerns about the safety of synthetic components, scientists are beginning to search for natural sources of antioxidants, especially essential oils (EOs). The combination of EOs may produce a higher scavenging profile than a single oil due to better chemical diversity in the mixture. Therefore, this exploratory study aims to assess the antioxidant activity of three EOs extracted from Cymbopogon flexuosus, Carum carvi, and Acorus calamus in individual and combined forms using the augmented-simplex design methodology. The in vitro antioxidant assays were performed using DPPH and ABTS radical scavenging approaches. The results of the Chromatography Gas-Mass spectrometry (CG-MS) characterization showed that citral (29.62%) and niral (27.32%) are the main components for C. flexuosus, while D-carvone (62.09%) and D-limonene (29.58%) are the most dominant substances in C. carvi. By contrast, β-asarone (69.11%) was identified as the principal component of A. calamus (30.2%). The individual EO exhibits variable scavenging activities against ABTS and DPPH radicals. These effects were enhanced through the mixture of the three EOs. The optimal antioxidant formulation consisted of 20% C. flexuosus, 53% C. carvi, and 27% A. calamus for DPPHIC50. Whereas 17% C. flexuosus, 43% C. carvi, and 40% A. calamus is the best combination leading to the highest scavenging activity against ABTS radical. These findings suggest a new research avenue for EOs combinations to be developed as novel natural formulations useful in food and biopharmaceutical products.
Tetraclinis articulata is a known traditional medicinal plant used to manage various ailments, such as diabetes, rheumatism and infectious diseases. This study aims to determine the chemical constituents of T. articulata essential oil (EO) and to evaluate its in vitro antibacterial, anti-candidal, antioxidant, anti-inflammatory and dermatoprotective properties. In addition, a computational docking approach was used to predict the potential antioxidant, antibacterial, antifungal, anti-inflammatory, and cytotoxic properties of the identified compounds. The volatile oil obtained by hydrodistillation was characterized using gas chromatography-mass spectrometry (GC-MS). The antioxidant activity of T. articulata EO was investigated using three complementary assays: DPPH, ABTS and FRAP. Lipoxygenase (5-LOX) and tyrosinase enzymes were used to assess the anti-inflammatory and dermatoprotective effects of this oil. Moreover, disc-diffusion technique, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays were employed for the antimicrobial screening. The GC-MS analysis revealed that bornyl acetate (41.80 %), α-pinene (17.97 %) and camphor (15.97 %) are the major components of the studied EO. Moreover, T. articulata EO has exhibited promising antioxidant effect on FRAP, DPPH, and ABTS experiments. It also significantly inhibited 5-LOX (IC50 = 67.82 ± 0.03 μg/mL) and tyrosinase (IC50 = 211.93 ± 0.02 μg/mL). The results of MIC and MBC assays indicated that T. articulata EO is able to inhibit the growth of all tested bacteria (Gram + and Gram -) and Candida species. The ratio of tolerance level indicated that the tested oil was bactericidal against the Gram + bacteria and Candida species, whereas it has a bacteriostatic behavior against the Gram- bacteria. In light of these findings, T. articulata EO may be suggested as a potential pharmaceutical agent to prevent inflammation and skin problems and may serve as a natural antimicrobial and antioxidant alternative for sustainable application in food products.