Introduction: Engeletin is the main active component in the engelhardia leaf that promotes circulation and removes stasis, and has hypoglycemic, hypolipidemic, and anti-inflammatory actions. The aim of this study was to develop an ultra-performance liquid chromatography- tandem mass spectrometry method to detect engeletin in plasma and tissues and investigate its absorption, distribution, and mechanism in mice, which could provide very useful information for its pharmacological effect in vivo.

Materials and Methods: Twenty-five mice were intraperitoneally injected with 20 mg/kg engeletin, and five mice were sacrificed using 4% chloral hydrate 0.25, 0.5, 2, 4, and 6 h later. The tissues (brain, kidney, heart, liver, spleen, and lung) and blood were collected. Acetonitrile precipitation was applied to remove protein and further process the mouse plasma and tissue homogenate samples. Multiple reactions monitoring mode in negative mode was used to quantify the engeletin.

Results and Conclusion: Linearity of engeletin in plasma and tissues was good (R2 > 0.995), within the range of 2-2,000 ng/mL in plasma and 2-2,000 ng/g in tissues, and the lower limit of quantitation was 2 ng/mL in plasma and 2 ng/g in tissues. Inter-day precision of engeletin in plasma or tissues (brain, kidney, heart, liver, spleen, and lung) was < 14%, and intra-day precision was < 15%. After the mice were intraperitoneally injected with engeletin (20 mg/kg), the distribution in kidney and liver was the highest, followed by blood, spleen, lung, heart, and brain. Engeletin concentration in the brain was low, suggesting that engeletin can penetrate through the blood brain barrier, which could also help with engeletin investigations of the brain.

简介：Engeletin是Engelhardia叶片中的主要活性成分，可促进血液循环并消除瘀滞，并具有降血糖，降血脂和抗炎作用。这项研究的目的是开发一种超高效液相色谱-串联质谱法来检测血浆和组织中的恩格列汀，并研究其在小鼠中的吸收，分布和机制，这可为其在体内的药理作用提供非常有用的信息。 。

材料与方法：25只小鼠腹膜内注射20 mg / kg恩格列汀，并在0.25、0.5、2、4和6小时后用4％水合氯醛杀死5只小鼠。收集组织（脑，肾，心脏，肝，脾和肺）和血液。应用乙腈沉淀去除蛋白质，并进一步处理小鼠血浆和组织匀浆样品。阴性模式下的多反应监测模式用于定量恩格列汀。

结果与结论：恩格列汀在血浆和组织中的线性良好（R2> 0.995），在血浆中2-2,000 ng / mL和组织中2-2,000 ng / g的范围内，定量下限为2 ng / mL在血浆中和2 ng / g在组织中。血浆或组织（脑，肾，心脏，肝脏，脾脏和肺脏）中恩格列汀的日间精确度小于14％，日间精确度小于15％。小鼠腹腔注射恩格列汀（20 mg / kg）后，在肾脏和肝脏中的分布最高，其次是血液，脾脏，肺，心脏和脑。大脑中的Engeletin浓度较低，表明engeengein可以穿透血脑屏障，这也可能有助于恩格列汀对大脑的研究。