Antioxidant and antiacetylcholinesterase activities of five plants used as Portuguese food spices

In the present work, we report the results of a study aimed at evaluating the antiradical activity, the antioxidant activity and the acetylcholinesterase (E.C. 3.1.1.7.) inhibitory capacity of essential oils, ethanol and boiling water extracts from five aromatic herbs growing wild in Portugal and used in traditional food preparations: fennel (Foeniculum vulgare), mint (Mentha spicata), pennyroyal (Mentha pulegium), rosemary (Rosmarinus officinalis) and wild thyme (Thymus serpyllum). The water extracts of M. spicata and M. pulegium showed the highest radical-scavenging activity (DPPH test) values (IC50 = 5.7 ± 0.4 and 8.9 ± 0.2 μg ml−1 respectively). This activity was higher than that found with the standard antioxidant BHT. The ethanol extracts of M. spicata, T. serpyllum and F. vulgare showed the highest antioxidant activities measured by the β-carotene/linoleic acid assay, IC50 = 36.9 ± 0.1, 41.2 ± 0.1 and 68.7 ± 0.1 μg ml−1, respectively. The inhibition of AChE was higher in the essential oil fraction. The highest activity was found for R. officinalis with an IC50 = 69.8 ± 0.1 μg ml−1.