Phytochemical study and antioxidant activity of two Moroccan Lamiaceae species: Nepeta nepetella subsp. amethystina and Sideritis arborescens Salzm. ex Benth.

Abstract

Medicinal plants are widely used in the treatment of numerous diseases. These plants synthetize a wide variety of bioactive metabolites that exhibit countless biological and pharmacological activities. Nepeta nepetella and Sideritis arborescens are aromatic and medicinal plants belonging to the Lamiaceae family. These species are used in folk medicine in the treatment of several diseases. The present investigation aims to carry out a phytochemical screening of the aqueous extracts of N. nepetella and S. arborescens to reveal the different groups of phytochemicals present in the polar extract of these species, to estimate the amounts of phenolic compounds including total polyphenols, total flavonoids, flavonols, tannins, anthocyanins, and hydroxycinnamic acids, and to evaluate their antioxidant capacity using radical scavenging activity, molybdenum and ferric reduction potentials, and lipid peroxidation inhibition effects. The results of this study showed that these two Lamiaceae species contain a wide variety of metabolites including terpenoids, cardiac glycosides, phenols, proteins, flavonoids, tannins, quinons, coumarins, saponins, essential oils, and reducing sugars. Moreover, the estimation of the amounts of different phenolic compounds showed that both species have important phenolic compounds contents including flavonoids, tannins, and hydroxycinnamic acids. The antioxidant tests showed that both species display good antioxidant activity in which S. arborescens exhibit the highest antioxidant potential. In conclusion, the findings of this study suggest that Nepeta nepetella and Sideritis arborescens have important amounts of antioxidant phenolic compounds that can be used in the treatment of several diseases.