Polyphenolic Profile, Antioxidant and Aorta Endothelium Effect of Michay (Berberis congestiflora Gay) Collected in the Araucanía region of Chile

Berries are an excellent source of bioactive compounds such as polyphenols and widely used in folklore medicine, particularly by Mapuches people in southern of Chile. The objective of this study was to conduct a phytochemical composition analysis of a hydroalcoholic extract of Berberis congestiflora Gay (BE) and to evaluate its potential as an antioxidant, the vasorelaxant effect as relaxation effects in rat aorta, plus the inhibitory enzyme potential in relation to chronic non-communicable diseases, including a possible underlying vasodilatory mechanism in isolated rat aorta. Antioxidant activities were assayed by oxygen radical absorbance capacity (ORAC), by scavenging DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2-azinobis-(3-ethylbenzothioazolin-6-sulfonic acid) radicals, and ferric reducing antioxidant power (FRAP). Vascular response of Berberis extract was studied by means of isometric tension recording experiments in ex vivo rat thoracic aortic rings model. Identification of the chemical compounds present in BE was determined by HPLC-DAD-MS for the first time. The BE caused, per se, a dose-dependent contraction at 100 and 1000 µg/mL, and relaxation of the aorta pre-contracted with phenylephrine at 100 and 1000 µg/ml, with maximum contraction of 71% and relaxation of 70% both at 1000 µg/mL. The extract induces calcium-mediated contraction, mainly by calcium release from the sarcoplasmic reticulum and, to a lesser extent, by extracellular Ca2+ influx. The relaxation mechanism was found to depend on the NO/cGMP pathway and the endothelium. The extract also demonstrated cholinesterase, glucosidase and amylase enzyme inhibitor capacities (IC50: 7.33 ± 0.32, 243.23 ± 0.3 and 27.21 ± 0.03 µg/mL, respectively). Docking calculations were additionally performed for a selection of compounds in the berries. These results demonstrate that berries are an excellent source of bioactive compounds with potential antioxidants and endothelium-dependent vasodilator effect, providing evidence for its traditional use and for the inhibition of enzymes, making it a promising candidate for the development of phytotherapeutic products, especially as a supplement against chronic diseases.