Polyphenolic Profile and Antioxidant and Aortic Endothelium Effect of Michay (Berberis congestiflora Gay) Collected in the Araucanía Region of Chile

Berries are an excellent source of bioactive compounds, particularly polyphenols, and have been widely used in folk medicine by the Mapuche people of southern Chile. In this study, a hydroalcoholic extract of Berberis congestiflora Gay (BE) was analyzed to determine its phytochemical composition and to evaluate its antioxidant capacity, vasorelaxant effects in rat aortas, and inhibitory activity on enzymes related to chronic non-communicable diseases, including exploration of a possible vasodilatory mechanism in isolated rat aortas. Antioxidant activity was assessed using Oxygen Radical Absorbance Capacity (ORAC), DPPH (2,2-diphenyl-1-picrylhydrazyl), and ABTS (2,2-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid)) radical scavenging assays, as well as ferric reducing antioxidant power (FRAP). Vascular responses to the Berberis extract were studied using isometric tension recordings in an ex vivo rat thoracic aortic ring model, and the chemical constituents of BE were identified for the first time by HPLC-DAD-MS. The extract itself produced a dose-dependent contraction at 100 and 1000 µg/mL and induced relaxation in phenylephrine-precontracted aortas at the same concentrations, with a maximum contraction of 71% and maximum relaxation of 70% at 1000 µg/mL. Mechanistically, the extract triggered calcium-mediated contraction primarily through calcium release from the sarcoplasmic reticulum and, to a lesser degree, via extracellular Ca2+ influx, while its relaxant effect depended on an intact endothelium and activation of the NO/cGMP pathway. In addition, the extract showed inhibitory activity against cholinesterase, glucosidase, and amylase, with IC50 values of 7.33 ± 0.32, 243.23 ± 0.3, and 27.21 ± 0.03 µg/mL, respectively, and docking studies were carried out for selected berry compounds. Overall, these findings indicate that these berries are a rich source of bioactive constituents with antioxidant properties and endothelium-dependent vasodilator effects, supporting their traditional use and highlighting their potential as enzyme inhibitors and as promising candidates for the development of phytotherapeutic products, particularly as supplements for chronic disease management.