Hunan Engineering Research Center of Veterinary Drug, College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan 410128, China.
Pharmacol Rep. 2013;65(5):1391-400. doi: 10.1016/s1734-1140(13)71498-1.
Sanguinarine (SA) is a quaternary benzo[c]phenanthridine alkaloid that is mainly present in the Papaveraceae family. SA has been extensively studied because of its antimicrobial, anti-inflammatory, antitumor, antihypertensive, antiproliferative and antiplatelet activities. Metabolic studies demonstrated that SA bioavailability is apparently low, and the main pathway of SA metabolism is iminium bond reduction resulting in dihydrosanguinarine (DHSA) formation. Nevertheless, the metabolic enzymes involved in SA reduction are still not known in detail. Thus, the aim of this study was to investigate the rat liver microsomes and cytosol-induced SA iminium bond reduction, and to examine the effects of cytosol reductase inhibitors on the reductive activity.
DHSA formation was quantified by HPLC. The possible enzymes responsible for DHSA formation were examined using selective individual metabolic enzyme inhibitors.
When SA was incubated with liver microsomes and cytosol in the absence of NAD(P)H, DHSA, the iminium bond reductive metabolite was formed. The reductase activity of the liver microsomes and cytosol was also enhanced significantly in the presence of NADH. The amount of DHSA formed in the liver cytosol was 4.6-fold higher than in the liver microsomes in the presence of NADH. The reductase activity in the liver cytosol was inhibited by the addition of flavin mononucleotide and/or riboflavin. Inhibition studies indicated that menadione, dicoumarol, quercetin and 7-hydroxycoumarin inhibited rat liver cytosol-mediated DHSA formation in the absence of NADH. However, only menadione and quercetin inhibited rat liver cytosol-mediated DHSA formation in the presence of NADH.
These results suggest that the SA iminium bond reduction proceeds via two routes in the liver cytosol. One route is direct non-enzymatic reduction by NAD(P)H, and the other is enzymatic reduction by possible carbonyl and/or quinone reductases in the liver cytosol.
血根碱（SA）是一种主要存在于罂粟科的季铵苯并菲啶生物碱。由于其具有抗菌、抗炎、抗肿瘤、降压、抗增殖和抗血小板作用，因此对其进行了广泛的研究。代谢研究表明，SA 的生物利用度显然较低，SA 代谢的主要途径是亚胺键还原，导致二氢血根碱（DHSA）的形成。然而，参与 SA 还原的代谢酶仍未详细了解。因此，本研究旨在研究大鼠肝微粒体和胞浆诱导的 SA 亚胺键还原，并考察胞浆还原酶抑制剂对还原活性的影响。
通过 HPLC 定量测定 DHSA 的形成。使用选择性的单个代谢酶抑制剂来研究可能负责 DHSA 形成的酶。
当 SA 在没有 NAD(P)H 的情况下与肝微粒体和胞浆孵育时，形成了亚胺键还原代谢物 DHSA。在 NADH 存在下，肝微粒体和胞浆的还原酶活性也显著增强。在 NADH 存在下，DHSA 在肝胞浆中的形成量比在肝微粒体中高 4.6 倍。在加入黄素单核苷酸和/或核黄素后，肝胞浆中的还原酶活性被抑制。抑制研究表明，在没有 NADH 的情况下，二苯甲酮、双香豆素、槲皮素和 7-羟基香豆素抑制大鼠肝胞浆介导的 DHSA 形成；而只有二苯甲酮和槲皮素抑制大鼠肝胞浆介导的 DHSA 形成在 NADH 存在的情况下。
这些结果表明，SA 亚胺键还原在肝胞浆中通过两条途径进行。一条途径是 NAD(P)H 的直接非酶还原，另一条途径是肝胞浆中可能的羰基和/或醌还原酶的酶促还原。
