Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem Echium plantagineum L. honey: Search of pyrrolizidine alkaloids and polyphenols, anti-inflammatory potential and cytotoxicity Rute Moreira, Fátima Fernandes, Patrícia Valentão, David M. Pereira ⁎ , Paula B. Andrade ⁎ REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira n.° 228, 4050-313 Porto, Portugal ARTICLE INFO Keywords: Honey Echium plantagineum L. Pyrrolizidine alkaloids Phenolic compounds Anti-inflammatory ABSTRACT For a long time, honey has been recognized for its health-promoting properties and, consequently, has been used in traditional medicine worldwide. Apart from the beneficial bioactive compounds found in this food (e.g. polyphenols), molecules with potentially harmful effects may also be present, such as pyrrolizidine alkaloids. Aiming the quality assessment of honeys produced from Echium plantagineum L., a species known for its content in pyrrolizidine alkaloids, this work was focused in the search of these alkaloids and of polyphenols in one monofloral and two multifloral honeys, using chromatographic techniques. Additionally, their cytotoxicity and anti-inflammatory potential were assessed in cellular models. Several polyphenols were determined, but no pyrrolizidine alkaloid was detected in the analysed honey samples. Honey extracts exhibited capacity to decrease NO levels in lipopolysaccharide-stimulated murine macrophage-like cells (RAW 264.7) up to 40% at con- centrations of 0.25 mg/mL. Therefore, this work highlights the health benefits of these honey samples. 1. Introduction Honey is a nutritious food consumed worldwide, being recognized for its health-promoting properties (Battino et al., 2019; Samarghandian, Farkhondeh, & Samini, 2017). Its consumption is as- sociated with a healthy diet, as it contains many beneficial bioactive compounds, including flavonoids and other polyphenols. However, some molecules with potentially harmful effects can also be found in honey, namely when it is produced from plants containing pyrrolizidine alkaloids (PA), which have been described as toxic (Wiedenfeld & Edgar, 2011). Phenolic compounds are secondary metabolites of plants and they are the main class of antioxidants in the human diet (Pandey & Rizvi, 2009). They have been attributed a preventive role in several diseases caused by oxidative stress, such as cancer and neurodegenerative dis- eases (Pandey & Rizvi, 2009). PA are also secondary metabolites pro- duced by plants, as a chemical defence against herbivores, being pre- sent in 3% of all flowering plants, mostly in three families: Asteraceae, Boraginaceae and Fabaceae (Cheeke, 1988). Several outbreaks and livestock losses due to their presence in relevant plants of both human and animal nutrition have been reported, particularly in developing countries, justifying the growing concern around this topic. Generally, the cause of intoxication is the use of contaminated feeds and crops, or the direct consumption of PA-containing plants (Edgar, Colegate, Boppré, & Molyneux, 2011; Griffin, Danaher, Elliott, Glenn Kennedy, & Furey, 2013). However, these molecules have also been extensively described in herbal teas, herbal medicines, dietary supplements, vege- tables, cereals, wheat grain, honey and pollen, as well as food products of animal source, such as meat and eggs (Edgar et al., 2011; Kempf et al., 2011). Intoxications with PA can be acute, sub-acute and chronic, each of them presenting different symptoms. Despite the well-known con- sequences of the consumption of PA in several food products, there is no official limit established for the maximum level of these compounds in food and feed. For PA to exert toxicity is necessary to occur bio- transformation, which takes place primarily in the liver through the action of cytochrome P450 monooxygenases located in the hepatocytes, reason why they are particularly known by their hepatotoxicity. https://doi.org/10.1016/j.foodchem.2020.127169 Received 8 November 2019; Received in revised form 4 April 2020; Accepted 25 May 2020 Abbreviations: PA, Pyrrolizidine alkaloids; DMSO, dimethyl sulfoxide; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; LPS, lipopolysaccharide; DMEM, Dulbecco’s Modified Eagle Medium; MEM, Minimum Essential medium; FBS, foetal bovine serum; SPE, solid phase extraction; HPLC, high performance liquid chromatography; DAD, diode array detector; NO, nitric oxide; SEM, standard error of the mean; iNOS, inducible nitric oxide synthase; NF-kB, nuclear factor-kB; AMPK, AMP-activated protein kinase; Nrf2, nuclear factor erythroid-2-related factor-2; ARE, antioxidant responsive element; DHPA, dehydropyrrolizidine alkaloids ⁎ Corresponding authors. E-mail addresses: up201408307@ff.up.pt (R. Moreira), mgfernandes@ff.up.pt (F. Fernandes), valentao@ff.up.pt (P. Valentão), dpereira@ff.up.pt (D.M. Pereira), pandrade@ff.up.pt (P.B. Andrade). Food Chemistry 328 (2020) 127169 Available online 27 May 2020 0308-8146/ © 2020 Elsevier Ltd. All rights reserved. T