Evaluation of solvent influence on phytochemical content and antioxidant activities of two Algerian endemic taxa: Stachys marrubiifolia Viv. and Lamium flexuosum Ten. (Lamiaceae)

Abstract

Introduction: Stachys and Lamium genera have been widely used in traditional medicine. This is the first study attempting to determine the biological active compounds, mineral elements content and in vitro antioxidant activities of two Algerian endemic taxa (Stachys marrubiifolia Viv. and Lamium flexuosum Ten.), as well as evaluating the solvent influence on our studied parameters. Methods: This experimental study conducted phytochemical screening, followed by mineral elements content determination. Extracts were prepared using various solvents with different polarities (water/methanol, ethyl acetate, and butanol), after that polyphenols, flavonoids, tannins, flavanols, and orthodiphenols levels were determined. In addition, the in vitro radical scavenging evaluation (DPPH, NBT/Riboflavin and FRAP assay) and the total antioxidant properties (훽-carotene/linoleic acid and phosphomolybdenum assay) were assessed. Results: The obtained results clearly showed mineral elements richness and demonstrated that different extracts contained various biological active compounds with substantial amounts (high content of flavonoids, medium content of orthodiphenols, anthocyanins as well as flavanols, and low content of total phenols as well as tannins). Ethyl acetate was shown to be the most effective for the extraction of these compounds. Also, we noted that all extracts had diverse antioxidant capacities with IC50 values varying between (0.18±0.05 and 3.12±0.18 mg/g), and the relative differences depended on species, fractions, and testing methods. Conclusion: Our study clearly shows that solvent extracts had a remarkable influence on all studied parameters, confirming the strong correlation between phytochemical constituents and antioxidant activities. Therefore, it justifies the use of these endemic taxa in traditional medicine.