School of Pharmacy, College of Pharmacy, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110, Taiwan.
Pharm Biol. 2012 Jun;50(6):760-5. doi: 10.3109/13880209.2011.631930. Epub 2012 Apr 3.
Wogonin is a flavone derivative isolated from Scutellaria baicalensis Georgi (Labiatae) root, which is a traditional Chinese drug used as an anti-inflammatory and for management of dysmenorrhea.
The effect of wogonin on the uterus has not yet been examined. We investigated the relaxant effects of wogonin on contractile activity of isolated uterine strips of rats.
The effect of wogonin on spontaneous uterine contraction, and uterine contraction induced by agonists, K⁺-depolarization and oxytocin in Ca²⁺-free solution was observed. To clarify the type of potassium channel, we tested the effects of 4-aminopyridine, tetraethylammonium and glibenclamide.
Wogonin reduced the contractile amplitude of uterine strip smooth muscle of rats in a dose-dependent manner. The concentration of wogonin for reducing the contraction amplitude by 50% (IC₅₀) on spontaneous contractions was 60.5 μM. Wogonin also inhibited the contraction induced by three agonists (oxytocin, prostaglandin F(2α) and acetylcholine). For the uterine strips pretreated with oxytocin in Ca²⁺-free solution or K⁺-depolarization, wogonin showed relaxant effect on the induced uterine contractions. In addition, whereas the inhibitive effect of wogonin on the contraction of uterine smooth muscle in rats could be partly blocked by 4-aminopyridine and tetraethylammonium, it was not influenced by glibenclamide.
Wogonin significantly inhibited the contraction of rat uterine smooth muscle probably through the inhibition of the inflow of extracellular calcium into cells via cell membrane, and intracellular release of calcium ions. In addition, the relaxant effect induced by wogonin might be due in part to the opening of voltage-dependent and large conductance Ca²⁺-activated K⁺ channels.
黄芩素是从唇形科黄芩（Scutellaria baicalensis Georgi）根中分离得到的一种黄酮衍生物，是一种传统的中药，具有抗炎和治疗痛经的作用。
黄芩素对子宫的作用尚未得到研究。本研究旨在探讨黄芩素对大鼠离体子宫平滑肌收缩活动的松弛作用。
观察了黄芩素对自发性子宫收缩以及激动剂、K⁺去极化和无钙溶液中催产素诱导的子宫收缩的影响。为了阐明钾通道的类型，我们测试了 4-氨基吡啶、四乙铵和格列本脲的作用。
黄芩素呈浓度依赖性降低大鼠子宫平滑肌收缩幅度。使收缩幅度降低 50%的黄芩素浓度（IC₅₀）对自发性收缩为 60.5 μM。黄芩素还抑制了三种激动剂（催产素、前列腺素 F₂α和乙酰胆碱）诱导的收缩。对于无钙溶液或 K⁺去极化预处理的催产素诱导的子宫收缩，黄芩素对诱导的子宫收缩显示出松弛作用。此外，黄芩素对大鼠子宫平滑肌收缩的抑制作用部分可被 4-氨基吡啶和四乙铵阻断，但不受格列本脲影响。
黄芩素显著抑制大鼠子宫平滑肌收缩，可能是通过抑制细胞外钙离子流入细胞内以及细胞内钙离子释放来实现的。此外，黄芩素诱导的松弛作用部分可能是由于电压依赖性和大电导钙激活钾通道的开放。
