Tachikawa E, Takahashi M, Kashimoto T
Department of Pharmacology, School of Medicine, Iwate Medical University, 020-8505, Morioka, Japan.
Biochem Pharmacol. 2000 Aug 1;60(3):433-40. doi: 10.1016/s0006-2952(00)00343-9.
The crude extract of magnolia bark, an herbal drug, inhibited the secretion of catecholamines from bovine adrenal chromaffin cells stimulated by acetylcholine (ACh) in a concentration-dependent manner (200-900 microg/mL). The extract also diminished the secretion induced by high K(+), which is a stimulus directly depolarizing the plasma membranes, but its inhibition was weaker than that of ACh-evoked secretion. beta-Eudesmol, honokiol, magnolol, and bornyl acetate, but not alpha- and beta-pinenes, all of which are ingredients of magnolia bark, greatly reduced ACh-evoked secretion. beta-Eudesmol and magnolol also inhibited high K(+)-induced secretion to an extent similar to that of ACh-evoked secretion. However, honokiol and bornyl acetate inhibited the secretion induced by high K(+) much less than the secretion evoked by ACh. ACh-induced Na(+) influx and ACh- or high K(+)-induced Ca(2+) influx into the cells were diminished by beta-eudesmol or honokiol. These results indicate that magnolia bark contains some effective components inhibiting the secretion of catecholamines from bovine adrenal chromaffin cells stimulated by ACh due to the antagonism of Na(+) and Ca(2+) influxes into the cells. However, inhibition by the extract of magnolia bark seems to be attributable to honokiol and bornyl acetate. Furthermore, the results indicate that the inhibitory effect of magnolia bark may be associated with its pharmacological effect on activities of the nervous system.
厚朴作为一种草药，其粗提物能浓度依赖性地（200 - 900微克/毫升）抑制乙酰胆碱（ACh）刺激牛肾上腺嗜铬细胞分泌儿茶酚胺。该提取物还能减少高钾（K⁺）诱导的分泌，高钾是一种直接使质膜去极化的刺激因素，但其抑制作用比ACh诱发的分泌作用弱。β-桉叶醇、厚朴酚、和厚朴酚以及乙酸龙脑酯（均为厚朴树皮的成分）能显著减少ACh诱发的分泌，而α-蒎烯和β-蒎烯则不能。β-桉叶醇和和厚朴酚对高钾（K⁺）诱导的分泌的抑制程度与对ACh诱发的分泌的抑制程度相似。然而，厚朴酚和乙酸龙脑酯对高钾（K⁺）诱导的分泌的抑制作用远小于对ACh诱发的分泌的抑制作用。β-桉叶醇或厚朴酚能减少ACh诱导的钠离子内流以及ACh或高钾（K⁺）诱导的钙离子内流进入细胞。这些结果表明，厚朴树皮含有一些有效成分，由于其对细胞内钠离子和钙离子内流的拮抗作用，从而抑制ACh刺激牛肾上腺嗜铬细胞分泌儿茶酚胺。然而，厚朴树皮提取物的抑制作用似乎归因于厚朴酚和乙酸龙脑酯。此外，结果表明厚朴树皮的抑制作用可能与其对神经系统活动的药理作用有关。
