Pure ethanol

Inflorescences and upper dried leaves from yarrow (Achillea millefollium L.) were purchased from a local herbalist (Murciana Herbolisteria, Murcia, Spain). The sun-dried plant from a Bulgarian variety was ground in a hammer mill (Premill 250, Lleal S.A., Granollers, Spain) and sieved to reduce its particle size (<500 μm). Then, the UAE extraction was carried out by using an ultrasonic device (Branson Digital Sonifier 250, Danbury, CT, USA) with a power of 200 W and frequencies of 60 kHz. For this purpose, 40 g of ground and sieved yarrow plant were added to 400 mL of pure ethanol (Panreac Madrid, Spain) for 30 min at 40 °C. An output of 70% with respect to the nominal amplitude was applied during extraction. Finally, the obtained yarrow extract (YE) was concentrated to a final concentration of 17.9 mg/mL by rotary evaporation at 35 °C (IKA RV-10 control, VWR, Madrid, Spain) and stored at −20 °C.

HPLC grade acetonitrile was obtained from Macron Fine Chemicals (Madrid, Spain) and formic acid (99%) from Acros Organics (Madrid, Spain). Pure ethanol (99.5%) was purchased from Panreac (Barcelona, Spain). 2,2′-Azobis (2-methylpropionamidine) dihydrochloride (AAPH), 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), fluorescein, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), phorbol 12-myristate 13-acetate (PMA), and (±)-6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox, 97%) were purchased from Sigma-Aldrich (Madrid, Spain). Phenolic acids authentic standards (HPLC purity ≥ 95%) were purchased from Sigma-Aldrich, Phytolab (Madrid, Spain), Cymit Química SL (Madrid, Spain) and Extrasynthese S.A. (Genay, France) as detailed in Supplementary Material (Table S1).