Monocrotaline (Crotaline)   中文名称: 野百合碱

OCT1 (IC50 = 36.8 μM); OCT2 (IC50 = 1852.6 μM)

野百合碱是一种天然存在的配体，具有很强的抗肿瘤作用和剂量依赖性细胞毒性。在 HepG2 细胞上测试时，野百合碱的 IC50 为 24.966 µg/mL，体外遗传毒性为 IC50 的 2 倍 [2]。

高血压大鼠模型可以通过使用野百合碱的动物建模来创建。在大鼠中，MCT 会导致肺血管综合征，其典型表现为肺心病、肺动脉高压 (PH) 和增殖性肺血管炎 [3]。野百合碱诱导的动物模型的优点是与临床前模型中人类肺动脉高压（PAH）的几个重要方面非常相似，例如血管重塑、平滑肌细胞增殖、内皮功能障碍、炎症细胞因子上调和右心室衰竭。 [4]。野百合碱的施用导致与外周出血（PH）发病机制相关的多个途径发生改变，例如刺激糖酵解、增殖标记物升高、肉碱稳态紊乱、炎症和纤维化生物标记物升高以及谷胱甘肽产生。减少[5]。给予单剂量野百合碱（60 mg/kg ip）的大鼠肺动脉压力显着升高，右心室肥厚和肺动脉结构重塑也增加。然后，给予黄芪甲苷 IV (ASIV)，剂量为 10 和 30 mg/kg/d，持续 21 天。通过增强肺动脉重塑和炎症，ASIV可以预防肺动脉高压[7]。野百合碱（60 mg/kg；腹腔注射；单剂量）3-4 周后诱导大鼠肺动脉高压 (PAH) 模型 [7]。在左肺切除大鼠模型中，野百合碱（60 mg/kg；腹腔注射；单剂量）表现出显着的抗肿瘤功效以及剂量依赖性细胞毒性[9]。使用 1 N HCl 溶解野百合碱，然后用无菌盐水稀释，并使用 1 N NaOH 将 pH 调至 7.4 [7]。

本研究利用体外稳定转染的HEK293细胞，系统地研究了山莨菪碱和野百合碱两种生物碱与有机阳离子转运蛋白OCT1、2、3、MATE1和MATE2-K的相互作用。山莨菪碱和野百合碱均抑制OCTs和MATE转运蛋白。对OCT1的最低IC50为12.9µmol·L-1的山莨菪碱，对OCT2的最高IC50为1.8 mmol·L-1野百合碱。Anisodine是OCT2的底物（Km=13.3±2.6µmol·L-1和Vmax=286.8±53.6 pmol/mg蛋白质/min）。Monocrotaline被确定为OCT1（Km=109.1±17.8µmol·L-1，Vmax=576.5±87.5 pmol/mg蛋白质/min）和OCT2（Km=64.7±14.8µmol•L-1，V max=180.7±22.0 pmol/mg蛋白/min）的底物，而不是OCT3和MATE转运蛋白。结果表明，OCT2可能对肾清除山莨菪碱很重要，OCT1负责野百合碱进入肝脏。然而，MATE1和MATE2-K都不能促进山莨菪碱和野百合碱的跨细胞转运。这些药物可能会在高OCT1表达（肝脏）和高OCT2表达（肾脏）的器官中积聚[8]。

细胞活力测定[2]
细胞类型： HepG2 细胞
测试浓度： 25、50、100 和 200 µg/mL
孵育时间：48小时
实验结果：诱导凋亡率呈剂量依赖性。

Astragaloside IV blocks monocrotaline‑induced pulmonary arterial hypertension by improving inflammation and pulmonary artery remodeling[7]
Male Sprague-Dawley rats, 8 weeks old weighing 200-230 g, were obtained from the Animal Center of Qiqihar Medical University. The protocol for the present study was approved by the Qiqihar Medical University Institutional Review Board (no. QMU-AECC-2018-27). The rats were housed in a temperature- and humidity-controlled environment with 12-h light/dark cycles. Food and water were available ad libitum. The experiments conformed to the National Institutes of Health guidelines concerning the care and use of laboratory animals, and all animal procedures were approved by the Animal Care and Use Committee of the Qiqihar Medical University. The rats were randomly assigned to 4 groups (8 rats per group) as follows: The control group, the monocrotaline (MCT) group, the MCT + 10 mg/kg/dahy ASIV (ASIV10) group, and the MCT + 30 mg/kg/day ASIV (ASIV30) group. To establish MCT-induced PAH, the rats were administered a single intraperitoneal injection of MCT (60 mg/kg), while the control group received the same volume of saline. MCT was dissolved in 1 N HCl, diluted in sterile saline and adjusted to pH 7.4 with 1 N NaOH. ASIV was initially dissolved in DMSO as a stock solution and further diluted in saline immediately prior to use; the final DMSO concentration was 0.5%. Within hours of the MCT injection, there were signs of pulmonary vascular endothelial damage, but without an increase in pulmonary artery pressure. By 2 weeks, pulmonary artery pressure began to increase, as previously described. At 2 days following the MCT administration, ASIV or the vehicle (0.5% DMSO in saline) were administered intraperitoneally once a day for 21 days.

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A total of 36 male specific-pathogen free Sprague-Dawley rats (age, 6–8 weeks; weight, 300–350 g) were kept in a conventional room at 22±2°C, a relative humidity of 55±10% and a 12-h light/dark cycle. Rats had access to food and water ad libitum. The rats were divided into the following three equal groups at random: Control group, where rats received no treatment; model group, where rats underwent a left pneumonectomy plus subcutaneous injection of 60 mg/kg monocrotaline (MCT), a natural ligand exhibiting dose-dependent cytotoxicity with potent antineoplastic activity, at 7 days following the procedure; PTX group, where rats underwent the same procedure as those in the model group plus administration of 2 mg/kg PTX via the caudal vein (21) daily for 1 week at 3 weeks following injection of MCT[9].

Absorption, Distribution and Excretion
After sc administration of monocrotaline /in rats/, 50-70% of the dose was found in urine as unchanged monocrotaline... monocrotaline (or metabolite) concentration were highest in the liver, kidney and stomach.
The pyrrolizidine alkaloid monocrotaline has been shown to cause hepatic necrosis and pulmonary hypertension in the rat. To better understand the mechanism of action, tissue distribution and covalent binding studies were conducted at 4 and 24 hr following administration of (14)C monocrotaline (60 mg/kg, 200 microCi/kg, sc). For the 4 hr study, the levels of monocrotaline equivalents were 85, 74, 67, 36, and 8 nmol/g of tissue for RBC, liver, kidney, lung, and plasma, respectively, while the covalent binding levels were 125, 132, 39, 64, 44 pmol/mg of protein for tissues as listed above. The 24 hr tissue distribution levels were 49, 25, 9, 10, 2 nmol/g of tissue for RBC, liver, kidney, lung, and plasma, respectively, while covalent binding was 74, 28, and 55 pmol/mg of protein for liver, kidney, and lung, respectively. We also studied the kinetics of (14)C monocrotaline (60 mg/kg, 10 microCi/kg, iv), which demonstrated rapid elimination of radioactivity with approximately 90% recovery of the injected radioactivity in the urine and bile by 7 hr. The plasma levels of radioactivity dropped from 113 nmol/g of monocrotaline equivalents to 11 nmol/g at 7 hr while RBC levels decreased from 144 to only 81 nmol/g at the same time point. The apparent retention of monocrotaline equivalents in the RBC suggests that this organ may act as the carrier of metabolites from the liver to other organs including the lung and may play a role in the pulmonary toxicity.

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Metabolism / Metabolites
Studies with monocrotaline have confirmed the formation of pyrrolic metabolites by the mixed-function oxidase system of the microsomal fraction of rat liver. Dehydromonocrotaline (monocrotaline pyrrole) is highly cytotoxic, producing pulmonary, cardiac, vascular and hepatic lesions similar to those produced by the parent alkaloid. It is a highly reactive alkylating agent which, on formation within the cell, reacts immediately with cell constituents to give soluble or bound secondary metabolites or hydrolyzes to the dehydroaminoalcohol, dehydroretronecine.
Using microsomes from livers of phenobarbital-pretreated male rats, all 13 alkaloids tested were metabolized to n-oxide and pyrrole formation. The 2 pathways appeared to be independent. Ratio of n-oxide to pyrrolic metabolites varied, depending on type of ester: it was highest for open diester alkaloids and lowest for 12-membered macrocyclic diesters and for monoesters. Monocrotaline was one of those tested.
The comparative metabolism of the pyrrolizidine alkaloid, (14)C monocrotaline, was studied using rat and guinea pig hepatic microsomes. ... Esterase hydrolysis accounted for 92% of the metabolism in the guinea pig; the rat displayed no esterase activity. This result may explain the guinea pig's resistance to pyrrolizidine alkaloid toxicity. Dehydropyrrole was found to be the major pyrrolic metabolite in the guinea pig, although colorimetric analysis indicated multiple pyrrolic moieties in the rat microsomal incubations.
This report demonstrates that an Ehrlich reagent positive metabolite of monocrotaline and senecionine is excreted in the urine of male rats as an N-acetylcysteine conjugate of (+/-)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine ... This finding suggests that reactive metabolites of pyrrolizidine alkaloids generated in the liver can survive the aqueous environment of the circulatory system as glutathione conjugates or mercapturic acids.
For more Metabolism/Metabolites (Complete) data for MONOCROTALINE (7 total), please visit the HSDB record page.

Interactions
Both SKF 525a and metyrapone protected older rats against monocrotaline-induced right heart and lung hypertrophy. Mixed-function oxidase inhibition was more effective than sulfhydryl replacement in attenuating monocrotaline toxicity. Protection was less in younger rats.
Dietary ethoxyquin protected mice against lethality as well as acute hepatotoxicity of monocrotaline as measured by levels of alanine and aspartate aminotransferases in plasma. Dietary cysteine (1%) also protected mice against the lethality but not the acute hepatotoxicity of the alkaloid. With the exception of ethoxyquin, none of the other feed additives increased liver glutathione levels. Glutathione S-transferase activity was significantly increased by either dietary ethoxyquin or cysteine using chlorodinitrobenzene as substrate. Dietary ethoxyquin produced an increase in hepatic cytochrome p-450 content and increases in the in vitro conversion of monocrotaline to pyrrole metabolites by liver microsomes. Since ethoxyquin protected mice against monocrotaline lethality and hepatotoxicity, despite no reduction in the in vivo activation of monocrotaline, the mechanisms involved are most probably a result of increased detoxication processes partly because of increased liver glutathione levels.
Dietary butylated hydroxyanisole (BHA) at levels of 0.25 and 0.75% protected young female mice against the acute toxicity of monocrotaline. Protective effect was associated with reduced levels of pyrrole metabolites in liver, decreased activity of hepatic aminopyrine demethylase, and reduced rate of in vitro microsomal conversion of monocrotaline to pyrrole metabolites. BHA also increased liver sulfhydryl levels and activity of cytosolic glutathione s-transferase. Dietary cysteine (1%) was less protective than BHA against monocrotaline toxicity. LD50 values of monocrotaline in control and cysteine-fed mice were 259 and 335 mg/kg, respectively.

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Non-Human Toxicity Values
LD50 Rat iv 92 mg/kg
LD50 Mouse ip 259 mg/kg
LD50 Rat oral 66 mg/kg
LD50 Mouse iv 261 mg/kg

[1]. The monocrotaline model of pulmonary hypertension in perspective. Am J Physiol Lung Cell Mol Physiol. 2012 Feb 15;302(4):L363-9.
[2]. Antineoplastic activity of monocrotaline against hepatocellular carcinoma. Anticancer Agents Med Chem. 2014;14(9):1237-48.
[3]. Mechanisms and pathology of monocrotaline pulmonary toxicity. Crit Rev Toxicol. 1992;22(5-6):307-25.
[4]. Exploring the monocrotaline animal model for the study of pulmonary arterial hypertension: A network approach. Pulm Pharmacol Ther. 2015 Dec;35:8-16.
[5]. Metabolic Changes Precede the Development of Pulmonary Hypertension in the Monocrotaline Exposed RatLung. PLoS One. 2016 Mar 3;11(3):e0150480.
[6]. Experimental animal models of pulmonary hypertension: Development and challenges. Animal Model Exp Med. 2022 Sep; 5(3):207-216.
[7]. Astragaloside IV blocks monocrotaline‑induced pulmonary arterial hypertension by improving inflammation and pulmonary artery remodeling. Int J Mol Med. 2021 Feb;47(2):595-606.
[8]. An in vitro study on interaction of anisodine and monocrotaline with organic cation transporters of the SLC22 and SLC47 families. Chin J Nat Med. 2019 Jul;17(7):490-497.
[9]. Effects of paclitaxel intervention on pulmonary vascular remodeling in rats with pulmonary hypertension. Exp Ther Med. 2019 Feb;17(2):1163-1170.

Monocrotaline can cause cancer according to an independent committee of scientific and health experts.
Monocrotaline is a pyrrolizidine alkaloid.
Monocrotaline has been reported in Crotalaria sessiliflora, Crotalaria retusa, and other organisms with data available.
A pyrrolizidine alkaloid and a toxic plant constituent that poisons livestock and humans through the ingestion of contaminated grains and other foods. The alkaloid causes pulmonary artery hypertension, right ventricular hypertrophy, and pathological changes in the pulmonary vasculature. Significant attenuation of the cardiopulmonary changes are noted after oral magnesium treatment.

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Mechanism of Action
The toxicology of monocrotaline is complex, and the mechanisms by which it causes lung injury, pulmonary hypertension, and right heart enlargement have remained elusive. ... Monocrotaline is bioactivated by the liver to a reactive, electrophilic pyrrole that travels via the circulation to the lung, where injury results. When low, iv doses of monocrotaline pyrrole are given to rats, a delay of several days occurs before lung injury and pulmonary hypertension become apparent. Moderate depletion of blood platelets around the time of the onset of lung injury lessens the subsequent development of right ventricular enlargement, suggesting a reduction in the pulmonary hypertensive response to monocrotaline pyrrole. This observation prompted a study of the role of platelet-derived mediators in the cardiopulmonary response to monocrotaline pyrrole. A stable analog of thromboxane A2(TxA2) caused a greater increase in right ventricular pressure in monocrotaline pyrrole treated rats compared to controls, and lungs isolated from monocrotaline pyrrole treated rats produced more TxB2 than those of controls. However, administration of drugs that either inhibited thromboxane synthesis or antagonized the effects of thromboxane did not afford protection from monocrotaline pyrrole in vivo. Serotonin, another vasoactive mediator released by platelets, caused an exaggerated vasoconstrictor response in isolated lungs from rats treated with monocrotaline pyrrole. Moreover, removal and inactivation of circulating serotonin by the pulmonary vasculature was impaired by treatment of rats with monocrotaline pyrrole. However, administration of serotonin receptor antagonists did not attenuate the cardiopulmonary effects of monocrotaline pyrrole in vivo. These results suggest that neither TxA2 nor serotonin is the sole mediator of the pneumotoxicity due to monocrotaline pyrrole. Thus, the mechanism by which platelets are involved in the pathogenesis of the pneumotoxic response to monocrotaline pyrrole remains an unsolved puzzle.
Monocrotaline propagates changes in the contractile response of arterial smooth muscle, changes in smooth muscle Na/K-ATPase activity, release of platelet factors, and decreased serotonin transport by vascular endothelial cells.
Effect of ip administration of monocrotaline on activities of hepatic epoxide hydrolase, and arylhydrocarbon hydroxylase was investigated in young, male long-evans rats. Monocrotaline failed to stimulate epoxide hydrolase while diminishing the activity of glutathione s-transferase, aminopyrine demethylase and AHH. There was no effect in vitro on hepatic drug-metabolizing enzymes studied except for slight stimulation of epoxide hydrolase activity and small reduction of aminopyrine demethylase activity.
... An active metabolite of monocrotaline, dehydromonocrotaline (DHM), alkylates guanines at the N7 position of DNA with a preference for 5'-GG and 5'-GA sequences. In addition, it generates piperidine- and heat-resistant multiple DNA crosslinks, as confirmed by electrophoresis and electron microscopy. On the basis of these findings, we propose that DHM undergoes rapid polymerization to a structure which is able to crosslink several fragments of DNA.

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Therapeutic Uses
/Exptl Ther/ Antitumor effects of 22 pyrrolizidine alkaloids and derivatives were studied in mice with adenocarcinomas 755, l-1210 leukemia or sarcoma 180, rats with im or sc walker 256 carcinomasarcoma and in kb carcinoma cell cultures; 1 compound each was also tested in mice with ascites ehrlich carcinoma and hamsters with plasmacytoma number 1. Significant activity against the solid tumors, by CCNSC standards (58% or more decrease in tumor size), was seen with monocrotaline (NSC-28693) in 3 of the above tumors and in p-1. Monocrotaline n-oxide was without significant activity in any of the systems tested.
/Exptl Ther/ Monocrotaline from crotalaria sessiliflora has been shown to be effective against human skin cancer and cancer of uterine cervix.

C16H23NO6

325.36

325.152

C, 59.07; H, 7.13; N, 4.31; O, 29.50

315-22-0

9415

Prisms from absolute alcohol
Colorless

1.4±0.1 g/cm3

537.3±50.0 °C at 760 mmHg

204ºC (dec.)(lit.)

278.7±30.1 °C

0.0±3.2 mmHg at 25°C

1.586

-0.37

96.3

2

7

0

23

575

5

O=C(O[C@]1([H])CCN2[C@]1([H])C(CO3)=CC2)[C@H](C)[C@@](C)(O)[C@@](C)(O)C3=O

QVCMHGGNRFRMAD-XFGHUUIASA-N

InChI=1S/C16H23NO6/c1-9-13(18)23-11-5-7-17-6-4-10(12(11)17)8-22-14(19)16(3,21)15(9,2)20/h4,9,11-12,20-21H,5-8H2,1-3H3/t9-,11+,12+,15+,16-/m0/s1

20-Norcrotalanan-11,15-dione, 14,19-dihydro-12,13-dihydroxy-, (13-alpha,14-alpha)- (9CI)

NSC 28693; NSC-28693; monocrotaline; Crotaline; 315-22-0; Monocrotalin; (-)-Monocrotaline; CHEBI:6980; Retronecine cyclic 2,3-dihydroxy-2,3,4-trimethylglutarate; (13-alpha,14-alpha)-14,19-Dihydro-12,13-dihydroxy-20-norcrotalanan-11,15-dione; NSC28693

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

注意： 请将本产品存放在密封且受保护的环境中（例如氮气保护），避免吸湿/受潮和光照。

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

1M HCl : 200 mg/mL (~614.70 mM)
DMSO : ~25 mg/mL (~76.84 mM)
H2O : ~2 mg/mL (~6.15 mM)

配方 1 中的溶解度: ≥ 2.5 mg/mL (7.68 mM) (饱和度未知) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: ≥ 2.5 mg/mL (7.68 mM) (饱和度未知) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 悬浮液。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: ≥ 2.08 mg/mL (6.39 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 20.8 mg/mL澄清的DMSO储备液加入到400 μL PEG300中，混匀；再向上述溶液中加入50 μL Tween-80，混匀；然后加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 4 中的溶解度: ≥ 2.08 mg/mL (6.39 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100μL 20.8mg/mL澄清的DMSO储备液加入到900μL 20％SBE-β-CD生理盐水中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 5 中的溶解度: ≥ 2.08 mg/mL (6.39 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100 μL 20.8 mg/mL 澄清 DMSO 储备液加入900 μL 玉米油中，混合均匀。

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配方 6 中的溶解度: ≥ 0.5 mg/mL (1.54 mM)(饱和度未知) in 1% DMSO 99% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。

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配方 7 中的溶解度: 4.17 mg/mL (12.82 mM) in PBS (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液; 超声助溶 (<60°C).

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配方 8 中的溶解度: 21 mg/mL (64.54 mM) in 20% HP-β-CD in Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液; 需要超声波和加温并加热至 53°C。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
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7、 以上所有助溶剂都可在 Invivochem.cn网站购买。