Thymus Algeriensis and Artemisia Herba-Alba Essential Oils: Cytotoxicity, Antibacterial and Antifungal Activities and Subacute Toxicity

Background: Bacterial resistance to antibiotics and cancer cells resistance to chemotherapeutic drugs are two major public health issues. Thymus algeriensis Boiss. & Reut. and Artemisia herba-alba Asso are two common medicinal plants used to combat several pathologies, including bacterial infections and different types of cancer. This study aims to assess the cytotoxic, antibacterial and antifungal activities of each single essential oil and their combination in vitro and in silico. Methods: The cytotoxicity was evaluated in vitro towards three cell lines: liver human hepatocyte carcinoma cell line, metastatic adenocarcinoma Michigan Cancer Foundation-7, and Anderson-Metastatic Breast 231. Antibacterial activity was tested by the disc diffusion method on three bacterial and two fungal strains. The subacute oral toxicity was performed to assess the potential toxicity of the studied Essential Oils (EOs) followed by an analysis of the blood biochemical parameters. Lastly, docking studies were performed to assess the antimicrobial effect of Thymol, Chrysanthenone, Camphor and Borneol. Results: The results of the cytotoxicity test showed that there is a good dose-effect correlation between the essential oils and their mixture for the range of concentrations tested (0-50 mu g/mL). However, the mixture induced a greater antiproliferative effect compared to the two oils tested separately against the three cell lines. The antibacterial and antifungal activities have revealed that the essential oil of Thymus (T.) algeriensis has an interesting antibacterial and antifungal activity against Bacillus subtilis and Penicillium digitatum with complete inhibition at 3.125 and 6.25 mu g/mL, respectively. Similarly, Staphylococcus (S.) aureus had a very high sensitivity to the essential oil of Artemisia (A.) herba-alba with an inhibitory concentration of 3.125 mu g/mL, as well as potent activity against Candida albicans and Penicillium digitatum, which were inhibited at 6.250 mu g/mL. The subacute toxicity results showed no toxic effects in mice treated with the essential oils mixture (150 mg/kg) compared to the control group (p < 0.05). The molecular docking showed that thymol exhibited the highest activity among the molecules studied. Conclusions: These studies show that the essential oils of T. algeriensis and A. herba-alba have great antiproliferative power important synergistic effect, and good antibacterial and antifungal activities.