Erica spiculifolia Salisb. (Balkan Heath): A Focus on Metabolic Profiling and Antioxidant and Enzyme Inhibitory Properties

<i>Erica spiculifolia</i> Salisb. (formerly <i>Bruckenthalia spiculifolia</i> Benth.) (Balkan heath) is renowned for its traditional usage as a diuretic, anti-inflammatory and antioxidant agent. For the first time, acylquinic acids, flavonoids and numerous proanthocyanidin oligomers were annotated/dereplicated by liquid chromatography-high-resolution mass spectrometry in methanol-aqueous extracts from <i>E</i>. <i>spiculifolia</i> aerial parts harvested at the early and full flowering stage. Chlorogenic acid and proanthocyanidin tetra- and trimer A, B-type together with quercitrin and (+) catechin were the predominant compounds in the semi-quantitative analysis. Neutral triterpenoids, triterpenoid acids and phytosterols were determined in apolar extracts by gas chromatography-mass spectrometry. Triterpenoid acids accounted for 80% of the total triterpenoid content, dominated by ursolic and oleanolic acid, reaching up to 32.2 and 6.1 mg/g dw, respectively. Ursa/olean-2,12-dien-28-oic acids and 3-keto-derivatives together with α-amyrin acetate as a chemotaxonomic marker, α-amyrenone, α- and β-amyrin were evaluated. Total phenolic and flavonoid contents were 83.85 ± 0.89 mg gallic acid equivalents/g and 78.91 ± 0.41 mg rutin equivalents/g, respectively. The extract actively scavenged DPPH and ABTS radicals (540.01 and 639.11 mg Trolox equivalents (TE)/g), possessed high potential to reduce copper and iron ions (660.32 and 869.22 mg TE/g, respectively), and demonstrated high metal chelating capacity (15.57 Ethylenediaminetetraacetic acid equivalents/g). It exhibited prominent anti-lipase (18.32 mg orlistat equivalents/g) and anti-tyrosinase (71.90 mg kojic acid equivalents/g) activity. The extract inhibited α-glucoside (1.35 mmol acarbose equivalents/g) and acetylcholinesterase (2.56 mg galanthamin equivalents/g), and had moderate effects on α-amylase, elastase, collagenase and hyaluronidase. Balkan heath could be recommended for raw material production with antioxidant and enzyme inhibitory properties.