In vitro study of the tocolytic effect of oroxylin A from <it>Scutellaria baicalensis </it>root
<p>Abstract</p> <p>Scutellariae Radix is one of the well-known tocolytic Chinese herbs. Oroxylin A is isolated from the root of <it>Scutellaria baicalensis</it>. The main syndrome of preterm birth is caused by uterus contractions from excitatory factors. Administration...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2009-03-01
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| Series: | Journal of Biomedical Science |
| Online Access: | http://www.jbiomedsci.com/content/16/1/27 |
| Summary: | <p>Abstract</p> <p>Scutellariae Radix is one of the well-known tocolytic Chinese herbs. Oroxylin A is isolated from the root of <it>Scutellaria baicalensis</it>. The main syndrome of preterm birth is caused by uterus contractions from excitatory factors. Administration of tocolytic agents is a strategy to prevent the occurrence of preterm births. The aim of this study was to investigate the effects of oroxylin A on contractions of uterine strips isolated from non-pregnant female Wistar rats (250~350 g). Contractions of the uterus were induced with acetylcholine (Ach) (1 μM), PGF<sub>2α </sub>(0.1 μM), oxytocin (10<sup>-3 </sup>U/ml), KCl (56.3 mM), tetraethylammonium (TEA; 1 and 10 mM), 4-aminopyridine (4-AP; 5 mM), glipizide (30 μM), a nitric oxide synthase (NOS) inhibitor (LNNA; 10<sup>-3</sup>M), a β-receptor blocker (propranolol; 10 μM), and a cyclooxygenase inhibitor (indomethacin; 60 μM). The inhibitory effects of the amplitude and frequency of spontaneous contractions by oroxylin A were antagonized with Ach (IC<sub>50 </sub>22.85 μM), PGF<sub>2α </sub>(IC<sub>50</sub>27.28 μM), oxytocin (IC<sub>50 </sub>12.34 μM), TEA; 1 and 10 mM (IC<sub>50 </sub>52.73 and 76.43 μM), 4-AP (IC<sub>50 </sub>67.16 μM), and glipizide (IC<sub>50</sub>27.53 μM), but oroxylin A was not influenced by Ca<sup>2+</sup>-free medium, LNNA, propranolol, or indomethacin. Otherwise, oroxylin A-mediated relaxation of the rat uterus might occur through opening of uterine calcium-dependent potassium channels or adenosine triphosphate potassium channel activation. This suggests that oroxylin A is the tocolytic principle constituent of <it>Scutellariae Radix</it>, and oroxylin A may provide a lead compound for new tocolytic drug development in the future.</p> |
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| ISSN: | 1021-7770 1423-0127 |