The effects of chrysin and pinostrobin, two flavonoids isolated from Teloxys graveolens leaves, on isolated guinea-pig ileum
The effects of chrysin and pinostrobin, two flavonoids isolated from Teloxys graveolens leaves, on isolated guinea-pig ileum
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DOI：
10.1016/s0944-7113(98)80042-1
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发表时间：
1998-12-01
期刊：
影响因子：
7.9
通讯作者：
Mata, R
中科院分区：
文献类型：
--
作者：
Meckes, M;Paz, D;Mata, R
用离体豚鼠回肠平滑肌评价了从Teloxys graveolens（藜科）的地上部分获得的球松酯和白杨素的药理作用。这两种黄酮类化合物都能抑制高浓度钾引起的收缩。通过测量每种产品在减少由60 mM K+去极化诱导的阶段性和较慢持续的紧张性收缩反应中的能力来确定松弛作用的效力。浓度高达5 × 10（-7）M的球松素和1 × 10（-7）M的白杨素诱导了无钙高钾培养基中回肠制备物对钙反应的非竞争性抑制。两种化合物对Ca ~（2+）的浓度-反应曲线均发生明显位移，EC_（50）呈浓度依赖性增加，最大反应降低。这些黄酮类化合物对K+诱发的收缩反应的相位成分和咖啡因诱导的收缩产生的抑制作用的检测，导致提出了这些化合物使用的不同的细胞内作用机制。获得的结果使我们得出结论，先前检测到的Teloxys graveolens粗提取物的松弛作用部分是由于白杨素和球松素的存在，其通过钙介导的机制抑制肠平滑肌收缩。由于粘膜上皮中钙流的调节可能在抗腹泻药物作用中起作用，因此在体外观察到的作用可以以同样的方式解释该植物用于治疗腹泻的流行用途。
The pharmacological effects of pinostrobin and chrysin obtained from the aerial parts of Teloxys graveolens (Chenopodiaceae) were evaluated using isolated in vitro guinea-pig ileal smooth muscle. Both flavonoids inhibited the contractions evoked by high concentrations of potassium. The potency of the relaxant effect was determined by measuring the capacity of each product in reducing the phasic and the slower sustained tonic contractile responses induced by depolarization with 60 mM K+. Concentrations up to 5 x 10(-7) M of pinostrobin and 1 x 10(-7) M of chrysin induced a non-competitive depression of responses to Ca2+ in ileum preparations bathed in a Ca2+-free, high K+ medium. Both compounds produced a rightward displacement of the concentration-response curves to Ca2+ with a concentration-depend ant increase of EC50 and a decrease of the maximal response. Examination of the inhibitory effect produced by these flavonoids on the phasic component of contractile response evoked with K+ and on the contraction induced with caffeine, led to propose a different intracellular mechanism of action used by these compounds.The results obtained led us to conclude that the previously detected relaxant effect of Teloxys graveolens crude extract is due in part, to the presence of chrysin and pinostrobin, which inhibit intestinal smooth muscle contractions by means of a calcium-mediated mechanism. Since the modulation of calcium fluxes in the mucosal epithelium may play a role in antidiarrheal drug action, the observed effects in vitro could in the same way explain the popular use of the plant for the treatment of diarrhea.