School of Chinese Medicine
Inhibitory effects of magnolol on distal colon of guinea pig in vitro
The influence of plant product magnolol (0-100 μM) on the contractile activity of isolated colonic muscle strips in guinea pig and related mechanism were investigated. Magnolol did not affect the base tone of colon muscle strips, but it dose-dependently inhibited 40 mM KCl-, 1 μM carbachol (CCh)- and 10 μM serotonin (5-HT)-induced contractions at concentrations higher than 10 μM. And also, magnolol inhibited the 5-HT- or CCh-induced muscle contraction in calcium-free buffer. Furthermore, magnolol inhibited the KCl-induced contraction under the condition of procaine. In addition, inhibition rate of nifedipine plus magnolol on muscle strips was lower than that of nifedipine alone. Moreover, magnolol dose-dependently decreased the velocity of pellet propulsion in the concentration range of 0.1-10 μM, and totally inhibited pellet propulsion at the concentration higher than 30 μM. Thus, it can be concluded that magnolol may 1) block receptor-operated cation channels and the voltage dependent Ca2+ channel, and 2) inhibit calcium release from the sarcolemmal membrane (SR) through blocking InsP3-sensitive and ryanodine-sensitive pathways. This explains, at least partially, that Cortex magnoliae officinalis exerts therapeutic effects on gastrointestinal disease through relaxation of GI tract smooth muscles. © 2006 Pharmaceutical Society of Japan.
Ca2+ channel, Magnolol, Smooth muscle
Source Publication Title
Biological and Pharmaceutical Bulletin
Pharmaceutical Society of Japan
Link to Publisher's Edition
Bian, Zhao Xiang, Gen Shui Zhang, Ka Leung Wong, Xu Guang Hu, Liang Liu, Zhijun Yang, and Min Li. "Inhibitory effects of magnolol on distal colon of guinea pig in vitro." Biological and Pharmaceutical Bulletin 29.4 (2006): 790-795.