*4.3. Antioxidant Activity Measured by the ABTS+*• *Method*

The highest antioxidant activity measured using the method with the ABTS+• radical was found in extracts from marjoram herb, garlic bulbs, stinging nettle herb and cleavers herb (Table 3). Marjoram is a commonly used spice herb, which, in addition to a high content of polyphenolic compounds, is also characterized by high antioxidant activity. Gramza-Michałowska et al. [41] determined the activity against ABTS•<sup>+</sup> radical in ethanolic solutions of marjoram herb at the level of 14.09 mg Trolox/g DM. In literature sources, the ABTS•<sup>+</sup> values in garlic bulbs (47.7 µM Trolox/g DM) are lower than those observed in this study [36]. The leaves of the cleavers in the study by Csepregi et al. [42] showed activity against the ABTS•<sup>+</sup> radical at the level of about 1.0 µM Trolox/µg of FM. Stinging nettle in the assessment of Rasa et al. [43] was characterized by activity against the ABTS•<sup>+</sup> radical at the level of 18 mM Trolox/100 g DM. The ABTS•<sup>+</sup> values obtained in the study (in the case of garlic, cleavers and stinging nettle) are, therefore, much higher than those observed in literature sources [42–44]. As in the case of the total polyphenol content analysis, the lowest antioxidant activity against the ABTS•<sup>+</sup> radical was found in the milk thistle sample.
