Chemical composition and biological properties of Thymus capitatus plants from Algerian high plains: A comparative and analytical study

The Lamiaceae family contains bioactive medicinal compounds mostly used as ornamental plants and traditional medicine, as well as in the food, cosmetics, and pharmaceutical sectors. Common uses include treating high cholesterol, diabetes, respiratory diseases, heart disease, and food poisoning. These medicinal uses were linked to their components and numerous biological properties, including antimicrobial and antioxidants. The goal of this study was to investigate the phytochemicals and biological activities of the petroleum ether extract of Thymus capitatus plant from two different regions of eastern Algeria (Souk ahras and Guelma), as well as to extract volatile oils using a Clevenger device and then analyze by using GC-MS. The results revealed that the total amount of phenolic compounds was better in the phenolic extract of Souk Ahras (3.41 mg GAE g−1), while the amount of flavonoid compounds was higher in the region of Guelma (26.31 mg QE g−1). Following the quantification of phenolic compounds by HPLC, we observed that the phenolic extracts contained most of the standard compounds in variable proportions. Furthermore, we tested the antioxidant activity of the phenolic compounds electrochemically with the cyclic voltammetry method. We concluded that the highest antioxidant content was recorded in the Guelma region extract (3.17 mg GAE g−1). We have also evaluated the antioxidant activity by a chemical method using 2,2-diphenyl-1-picrylhydrazyl, and the results showed that the Guelma extract exhibited a high effectiveness in terms of IC50% values. When extracting the volatile oils, it was found that the highest yield was in the Guelma region