Vasorelaxant effects of the extracts and some flavonoids from the buds of Coreopsis tinctoria. (September 2013)

• Record Type: Journal Article
• Authors: Sun, Yu-Hua; Zhao, Jun; Jin, Hong-Tao; Cao, Yan; Ming, Ting; Zhang, Lan-Lan; Hu, Meng-Ying; Hamlati, Hasimu; Pang, Shi-Bin; Ma, Xue-Ping
• Is Part Of: Pharmaceutical biology. Volume 51:Number 9(2013:Sep.)
• Page Start: 1158
• Page End: 1164
• Publication Date: 2013-09
• Subjects: Pharmacognosy -- Periodicals; Materia medica, Vegetable -- Periodicals; 615.321
• DOI: 10.3109/13880209.2013.782320
• Languages: English
• ISSNs: 1388-0209

Abstract

<abstract> <title>Abstract</title> <p> <italic>Context</italic>: The buds of <italic>Coreopsis tinctoria</italic> Nutt (Compositae) are used in the treatment of hypertension in the Uyghur folk medicine in China.</p> <p> <italic>Objective</italic>: To investigate vasorelaxant properties of extracts and some flavonoids from <italic>C. tinctoria</italic> (CT) and their underlying mechanisms in isolated rat thoracic aortic rings.</p> <p> <italic>Materials and methods</italic>: Vasorelaxant effects of ethanol extracts of CT (CTA) and its flavonoids as well as water–ethanol eluates from CTA by AB-8 resins (CTAA∼CTAF) were evaluated on rat aortic rings pre-contracted with phenylephrine (PE, 1 µM) or high KCl (60 µM). We evaluated the effect of CTA, CTAD and CTAE on PE-induced contraction in a Ca<sup>2+</sup>-free medium and a dose–effect curve of Ca<sup>2+</sup> in pre-contracted ring with high KCl.</p> <p> <italic>Results</italic>: Endothelial removal did not modify the effect of CTAD and CTAE (3.00 g/L) neither on PE-pre-contracted rings (164.78 ± 21.44 and 191.47 ± 16.75%) nor on KCl-pre-contracted rings (75.68 ± 10.76 and 125.14 ± 17.41%) compared with intact-endothelium rings pre-contracted with high KCl (100.49 ± 17.30 and 110.81 ± 16.33%). CTAD and CTAE (3.00 g/L) down-regulated the dose–effect curve of Ca<sup>2+</sup> in pre-contraction with high KCl, and inhibited the pre-contraction with PE in a Ca<sup>2+</sup>-free medium (<italic>p</italic> < 0.05). Seven flavonoids were obtained from CTAD, of which luteolin (<bold>5</bold>) and quercetin (<bold>6</bold>) were found to be the most effective relaxation in rings precontracted with PE (EC<sub>50</sub>: 0.006 and 0.039 g/L, <italic>p</italic> < 0.05) or high KCl (EC<sub>50</sub>: 0.023 and 0.045 g/L, <italic>p</italic> < 0.05).</p> <p> <italic>Discussion and conclusion</italic>: These data demonstrated the vasorelaxant effect of CT, and its mechanism is likely due to an inhibitory effect on calcium movements through cell membranes.</p> </abstract>