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Nitric Oxide‐Mediated Nanomolar Vasodilator Potencies of Glycosylated Anthocyanins do not Correlate with Redox Potential
Author(s) -
GarciaHuidobro J Pablo,
Calfio Camila,
Donoso M Veronica,
Donoso Francisca,
Silva Camila
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.lb401
Subject(s) - chemistry , vasodilation , antioxidant , nitric oxide , biochemistry , pharmacology , endothelium , biology , endocrinology , organic chemistry
Calafate is an endemic Patagonian shrub ( Berberis Microphylia ); its berries are rich in polyphenols, including 3‐glycosylated anthocyanins (GA, delphinidin, petunidin or malvidin) or mono or disaccharide conjugated quercetin (Q). The chemical profile of Calafate berries is well characterized and indicates its high redox potential; pharmacological properties are virtually unknown. From ethno‐pharmaceutical reports we hypothesized that Calafate polyphenols are vasodilators and ascertained whether this effect is related to their cell antioxidant activity (CAA). Vascular responses of GA and Q were assessed perfusing the intact rat arterial mesenteric bed or following endothelium denudation. The role of NO was assessed in mesenteries perfused with an eNOS inhibitor (L‐NNA). Luminally accessible NO was determined by chemiluminescence; intracellular NO was quantified by DAF fluorescence in isolated mesentery endothelial cells. Antioxidant capacity was quantified either by 1,1‐Diphenyl‐2‐picryl‐hydrazyl antioxidant assay (DPPH) or by CAA assessment. Extracellular ATP was assessed by chloroacetaldehyde derivatization to yield fluorescent purines; the nucleotide is related to NO production in endothelial cells. GA proved potent vasodilators with EC50s of 84.1 ± 0.3, 65.8 ± 0.4 and 17.7 ± 0.1 nM, respectively; aglycones exhibited similar EC50s. The maximal effect of GA did not exceed 56 ± 3.7% efficacy compared to acetylcholine (EC50 was 43.4 ± 0.1 nM with 100% efficacy) while the Q EC50 was 12.8 ± 0.1 μM, with 99 ± 4.1%. The GA‐induced vasodilatation was totally endothelium‐dependent; while the Q response showed partial endothelium‐dependence. The degree of GA vasodilatation correlated with luminal NO (r 2 = 0.83), confirming NO as the final intracellular signal. 30 μM Q increased both extracellular ATP secretion from endothelial cells plus intracellular DAF‐fluorescence (P<0.05), an indication that part of the Q response involves NO as the final effector. While Q exhibited the highest antioxidant effect in both the DPPH or CAA (p<0.01), the GA showed a 60‐fold lower potential than Q in the CAA test, indicating that the CAA is not related to its vasodilator profile, which apparently relies on eNOS allosteric modulation. In sum, GA are novel and potent endothelium‐dependent vasodilators, linked to modulation of NO production. Support or Funding Information Funded by FONDECYT 117‐0842 and 21141226 to CC and CEDENNA FB0807 This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .