We evaluated the effects of cadmium on phenolic composition of Erica andevalensis, an endemic protected heather that grows in mine affected soils. Plants cultivated under laboratory-controlled conditions were exposed to acute doses of cadmium to investigate the mechanisms this species possesses to survive in the presence of toxic metals in its natural habitat. Cadmium increased the total levels of phenolics and flavonoids compounds, and the total antioxidant capacity. Cinnamic acid derivatives, epicatechin, and rutin were increased in the presence of cadmium when applied in levels that did not alter the ratio of chlorophylls. Phenolic compounds play an important role in the metabolism of E. andevalensis to survive in heavy metal polluted soils. 1. Introduction Erica andevalensis Cabezudo and Rivera is an endemic species of South Western Iberian Peninsula, which only grows on soils affected by mining activity (outskirts of the mines, river banks of Tinto and Odiel Rivers) [1–3]. E. andevalensis flowers in soils and sediments highly polluted by a broad range of metals, which include cadmium [4–6]. Cadmium has no known physiological function in plants, and it is a highly toxic metal due to its reactivity with S and N atoms in amino acids [7]. It is also known to affect cellular structures and produce membrane damage, disruption of the electron transport, inhibition/activation of enzymes, and alteration of DNA [8]. Although cadmium does not belong to the Fenton-type class of metals, it is known to trigger lipid peroxidation in tissues at early exposure times, and several studies have shown the activation of antioxidative defences against cadmium toxicity [9]. Phenolic compounds have been described as electron-donating agents, and therefore they can act as antioxidants [10], acting as reducing agents, hydrogen donors, and singlet oxygen quenchers and preventing the evolution of oxidant-free radical and reactive species derived from metal catalysis by Fenton-like reactions [11, 12]. Moreover, it has been suggested that phenolics may act as biomarkers of metal exposure [13]. Previous studies detected a different phenolic composition in E. andevalensis compared with other heathers growing both in polluted and unpolluted soils [14], and, when grown under controlled conditions in the laboratory, acute exposure to cadmium-induced changes in the total antioxidant activity [15] and in the ascorbate and glutathione levels, and also the activity of the antioxidant enzymes [16]. The aim of the present study is to determine the phenolic composition of E. andevalensis in
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