コネッシン

解説コネシン．ネリイン(neriine)，ロケシン(roquessine)ともいう．ガガイモ科低木Holarrhena antidysentericaの枝皮および根皮に含有されるステロイドアルカロイド．クルチアルカロイドの一つでもある．無色の板状結晶．融点127～129 ℃．[α]20D＋25°(エタノール)．アメーバ赤痢の治療に用いられ，エメチンに比べておう吐の副作用がない．抗菌性がある．ピクリン酸塩は黄色の針状晶．融点222～224 ℃．

用途薬理作用研究用。

説明Conessine is a naturally occurring steroid alkaloid found in a number of plant species from the Apocynaceae family, which have been used in traditional herbal medicine as a treatment for amoebic dysentery. In a radioligand-based high-throughput screen, conessine demonstrated high affinity for both rat and human histamine H3 receptors (Kis = 5.2 and 24.5 nM, respectively) and high selectivity against histamine receptors H1, H2, and H4. Though conessine potently blocks H3 agonist-stimulated GTPγS binding in cell- and tissue-based functional assays and efficiently crosses the blood-brain barrier, it has a poor rate of CNS clearance.

使用Conessine is a steroidal dibasic alkaloid with a rigid steroid-based skeleton. Conessine is a potent and selective histamine H3 receptor antagonist.

純化方法It crystallises from acetone, sublimes at 95o/0.01mm and boils at 0.1mm with bath temperature at 220o. The dihydrochloride has m >340o (browns at 235o and decomposes at 338-240o) and has [] D +9.3o (c 2, H2O). [Marshall & Johnson J Am Chem Soc 84 1458 1962, Beilstein 22 III/IV 4382.]