Comparative evaluation of chemical composition, antioxidant capacity, and some contaminants in six Moroccan medicinal and aromatic plants

Medicinal and aromatic plants (MAPs) are an important source of nutrients and natural remedies. Some MAPs become industrial crops grown worldwide for their nutritional and medicinal values. Here, we aimed at comparing six MAPs in terms of mineral composition, crude protein, antioxidant activity, essential oil composition, and some contaminants (heavy metals and pesticides). The investigated MAPs belong to two botanical families namely Asteraceae (Artemisia herba-alba) and Lamiaceae (Lavandula dentata, Mentha spicata, Origanum vulgare, Rosmarinus officinalis, and Thymus vulgaris). Our outcomes revealed that the studied MAPs are rich in minerals (especially K, Ca, and Mg) and proteins (10.5 ± 0.3–15.0 ± 0.4%). Heavy metals and pesticides were found to be lower than the permissible limits in plants. Regarding essential oil composition, camphor was found to be the major compound in A. herba-alba and L. dentata, borneol in O. vulgare and T. vulgaris, d-carvone in M. spicata, and 1,8-cineole in R. officinalis. The studied plants had high total phenolic (up to 35.01 mg GAE/g DM) and flavonoid content (up to 54.38 mg GAE/g DM) important antioxidant capacity as revealed by DPPH (up to 35.02 ± 0.17 mg AAE/g DM) and FRAP (up to 774.85 ± 0.88 μmol TE/g DM). This study provides scientific data that could be exploited for better use of these plants for several applications.