Beneficial effects of hydroalcoholic extract and flavonoids from Zuccagnia punctata in a rabbit model of vascular dysfunction induced by high cholesterol diet

• Published in: Medicinal chemistry research Vol. 26; no. 10; pp. 2336 - 2344
• Main Authors: Roco, Julieta, Alarcón, Gabriela, Sierra, Liliana, Zampini, Iris Catiana, Ines Isla, María, Jerez, Susana
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2017; Springer Nature B.V
• Subjects: Acetylcholine; Acids; Angiotensin; Angiotensin II; Antagonists; Aorta; Arteries; Biochemistry; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cholesterol; Contraction; Equivalence; Flavonoids; Gallic acid; Herbal medicine; High cholesterol diet; Hypercholesterolemia; Isometric; Original Research; Pharmacology/Toxicology; Phenylephrine; Rabbits; Veins & arteries; Rabbit aorta; Flavonoids; Hypercholesterolemia; Vascular dysfunction; Angiotensin II
• ISSN: 1054-2523; 1554-8120
• DOI: 10.1007/s00044-017-1934-6

This study evaluated the effects of a Zuccagnia punctata standardized hydroalcoholic extract (ZpE) and three of its major flavonoids [2′,4′-dihydroxychalcone (DHC), 7-hydroxyflavanone (HF) and 3,7-dihydroxyflavone (DHF)] on the vascular reactivity of aortic rings with endothelial dysfunction induced by feeding rabbits on a high cholesterol diet. Rabbits were fed with either normal chow or a diet containing 1% cholesterol for 5–6 weeks. Isometric contractions were measured. Concentration response curves to ZpE (range from 4 × 10 −2 to 4 × 10 µg gallic acid equivalent/ml), DHC, DHF or HF (range from 10 −9 to 10 −4  M) showed concentration-dependent relaxation of arteries pre-contracted with phenylephrine. ZpE (4 × 10 −2 , 4 × 10 −1 and 4 µg gallic acid equivalent/ml), HF (10 −9 , 10 −7 , 10 −5  M), DHC (10 −9  M) and DHF (10 −9  M) added to the bath improved acetylcholine affinity. Pre-treatment of arteries with ZpE (4 × 10 −2  µg gallic acid equivalent/ml) and DHC (10 −9  M) reduced phenylephrine-induced contraction. Incubation with the higher dose of ZpE (4 µg gallic acid equivalent/ml) reduced the angiotensin II-maximal contraction ( C max ) acting as a non-competitive antagonist, while DHC and DHF (10 −5  M) caused a non-parallel rightward of the angiotensin II-concentration response curves and reduced the C max acting as mixed antagonists. ZpE (4 × 10 −2  µg gallic acid equivalent/ml), DHC and DHF (10 −9  M) caused a rightward displacement of angiotensin II-concentration response curves acting as competitive antagonists. In conclusion, the present study demonstrated that a ZpE and its major flavonoids had beneficial effects in arteries with vascular dysfunction induced by hypercholesterolemia. Therefore its use as herbal medicine to prevent cardiovascular risks factors may be promising.