The antioxidant and enzyme inhibitory properties of methanolic extracts from four aromatic plants used in traditional medicine and food [Calamintha nepeta (L.) Savi subsp. nepeta, Helichrysum italicum subsp. picardii Franco, Mentha spicata L. and Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens] were evaluated. The extract from O. vulgare exhibited the strongest DPPH (IC50 of 4.65 ± 0.12 µg/ml) and ABTS (1479.56 ± 12.29 µmolTE/gextract) scavenging capacities, as well as the largest ferric reducing ability (1746.76 ± 45.11 µmolAAE/gextract). This extract also showed the highest total phenolic content (1597.20 ± 24.10 µmolGAE/gextract) and although HPLC-DAD analysis revealed rosmarinic acid as the main compound of the extract, other compounds seem to be involved in the antioxidant activity. Furthermore, the extract from H. italicum, which was found to be rich in caffeoylquinic and dicaffeoylquinic acids and in pinocembrin, showed the highest inhibitory potential against acetylcholinesterase, tyrosinase and α-glucosidase. Overall, the results obtained validate the usefulness of the studied plants as valuable sources of natural agents beneficial for human health.
Keywords: Antioxidants; Curry plant; Lesser calamint; Oregano; Phenolic compounds; Spearmint.