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

ROCO, JULIETA; ALARCÓN, GABRIELA; SIERRA, LILIANA; ZAMPINI, CATIANA; ISLA, MARÍA INES; JEREZ, SUSANA

MEDICINAL CHEMISTRY RESEARCH

BIRKHAUSER BOSTON INC

Año: 2017

1054-2523

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 (CD) or a diet containing 1% cholesterol (HD) for 5-6-weeks. Isometric contractions were measured. Concentration response curves (CRC) to ZpE (range from 4.10-2 to 4.10 μg GAE/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 GAE/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 GAE/ml) and DHC (10-9 M) reduced phenylephrine-induced contraction. Incubation with the higher dose of ZpE (4μg GAE/ml) reduced the angiotensin II- maximal contraction (Cmax) acting asa non-competitive antagonist, while DHC and DHF (10-5 M) caused a non-parallelrightward of the angiotensin II-CRC and reduced the Cmax acting as mixedantagonists. ZpE (4.10-2 μg GAE/ml), DHC and DHF (10-9 M) caused a rightwarddisplacement of angiotensin II- CRC 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.