Traditional ethnomedical use of plants is recognized as an important potential source of compounds used in mainstream medicine. Herein, the in vitro antioxidant properties, nutrients and phytochemical composition of six medicinal plants widely used in the north-eastern Portuguese region were evaluated. The antioxidant activity was screened through: radical scavenging effects, reducing power, and inhibition of lipid peroxidation in brain homogenates. Nutrients and phytochemical characterization included determination of sugars by HPLC-RI, fatty acids by GC-FID, tocopherols by HPLC-fluorescence, phenolics, flavonoids, carotenoids and ascorbic acid, by spectrophotometric techniques. Rubus ulmifolius flowers revealed the highest antioxidant activity, and the highest contents in phenolics. flavonoids, ascorbic acid and lycopene. Castanea sativa flowers revealed the highest concentration of individual and total tocopherols, and total sugars, including the reducing sugars glucose and fructose. Helichrysum stoechas aerial parts gave the highest levels of beta-carotene. Matricaria recutita aerial parts revealed the highest PUFA levels, including linoleic acid. The studied medicinal plants have interesting antioxidant properties and a phytochemical composition that could provide scientific evidence for some folk uses in the treatment of diseases related to the production of ROS and oxidative stress, but further experiments are required to explore the mechanisms of action.
