Zhiqi Yin

Cholesterol-lowering effects and potential mechanisms of different polar extracts from Cyclocarya paliurus leave in hyperlipidemic mice

ETHNOPHARMACOLOGICAL RELEVANCE Cyclocarya paliurus Batal., native only to China, is widely consumed as a Chinese traditional folk medicine for the prevention and treatment of hyperlipidemia, obesity, and diabetes. The aim of the study is to investigate the cholesterol-lowering effect and potential mechanisms of different polar extracts from Cyclocarya paliurus leaves in mice fed with high-fat-diet. MATERIALS AND METHODS Cyclocarya paliurus leaves extracts were orally administered to diet-induced hyperlipidemic mice for 4 weeks. Simvastatin was used as a positive control. Body weight, food intake, histopathology of liver and adipose tissues, hepatic and renal function indices, lipid profiles in the serum and liver were evaluated. Total bile acid concentrations of the liver and feces were also measured. Furthermore, the activities and mRNA expression of cholesterol metabolism-related enzymes including 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, cholesterol 7α-hydroxylase (CYP7A1) and acyl-CoA cholesterol acyltransferase 2 (ACAT2) in the livers of the mice were analyzed. LC-MS detection was performed to identify the components in the active fraction of Cyclocarya paliurus extracts. RESULTS Different Cyclocarya paliurus polar extracts, especially ChE reduced the levels of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and hepatic TC and TG, enhanced the level of serum high-density lipoprotein cholesterol (HDL-C), restored hepatic and renal function indices and histomorphology. HMG-CoA reductase activity and mRNA expression were decreased, while CYP7A1 activity and mRNA expression as well as the level of fecal and hepatic bile acid were increased by ChE. LC-MS analysis of ChE revealed the presence of six main triterpenoids, which might be responsible for its antihyperlipidemic bioactivity. CONCLUSIONS Evidently ChE possesses the best antihyperlipidemic activity, and the cholesterol-lowering effect is at least partly attributed to its role in promoting the conversion of cholesterol into bile acids by upgrading the activity and mRNA expression of CYP7A1 and inhibiting those of HMG-CoA reductase to lower the cholesterol biosynthesis.

Two triterpeniods from Cyclocarya paliurus (Batal) Iljinsk (Juglandaceae) promote glucose uptake in 3T3-L1 adipocytes: The relationship to AMPK activation

PURPOSE The current study investigated the efficacy of Cyclocarya paliurus chloroform extract (CPEC) and its two specific triterpenoids (cyclocaric acid B and cyclocarioside H) on the regulation of glucose disposal and the underlying mechanisms in 3T3-L1 adipocytes. METHODS Mice and adipocytes were stimulated by macrophages-derived conditioned medium (Mac-CM) to induce insulin resistance. CPEC was evaluated in mice for its ability by oral glucose tolerance test (OGTT) and insulin tolerance test (ITT). To investigate the hypoglycemic mechanisms of CPEC and its two triterpenoids, glucose uptake, AMP-activated protein kinase (AMPK) activation, inhibitor of NF-κB kinase β (IKKβ) phosphorylation and insulin signaling transduction were detected in 3T3-L1 adipocytes using 2-NBDG uptake assay and Western blot analysis. RESULTS Mac-CM, an inflammatory stimulus which induced the glucose and insulin intolerance, increased phosphorylation of IKKβ, reduced glucose uptake and impaired insulin sensitivity. CPEC and two triterpenoids improved glucose consumption and increased AMPK phosphorylation under basal and inflammatory conditions. Moreover, CPEC and its two triterpenoids not only enhanced glucose uptake in an insulin-independent manner, but also restored insulin-mediated protein kinase B (Akt) phosphorylation by reducing the activation of IKKβ and regulating insulin receptor substrate-1 (IRS-1) serine/tyrosine phosphorylation. These beneficial effects were attenuated by AMPK inhibitor compound C, implying that the effects may be associated with AMPK activation. CONCLUSIONS CPEC and its two triterpenoids promoted glucose uptake in the absence of insulin, as well as ameliorated IRS-1/PI3K/Akt pathway by inhibiting inflammation. These effects were related to the regulation of AMPK activity.

Evaluation of hypericin: effect of aggregation on targeting biodistribution.

Hypericin (Hy) has shown great promise as a necrosis-avid agent in cancer imaging and therapy. Given the highly hydrophobic and π-conjugated planarity characteristics, Hy tends to form aggregates. To investigate the effect of aggregation on targeting biodistribution, nonaggregated formulation (Non-Ag), aggregated formulation with overconcentrated Hy in dimethyl sulfoxide (Ag-DMSO) solution, and aggregated formulation in water solution (Ag-water) were selected by fluorescence measurement. They were labeled with ¹³¹I and evaluated for the necrosis affinity in rat model of reperfused hepatic infarction by gamma counting and autoradiography. The radioactivity ratio of necrotic liver/normal liver was 17.1, 7.9, and 6.4 for Non-Ag, Ag-DMSO, and Ag-water, respectively. The accumulation of two aggregated formulations (Ag-DMSO and Ag-water) in organs of mononuclear phagocyte system (MPS) was 2.62 ± 0.22 and 3.96 ± 0.30 %ID/g in the lung, and 1.44 ± 0.29 and 1.51 ± 0.23 %ID/g in the spleen, respectively. The biodistribution detected by autoradiography showed the same trend as by gamma counting. In conclusion, the Non-Ag showed better targeting biodistribution and less accumulation in MPS organs than aggregated formulations of Hy. The two aggregated formulations showed significantly lower and higher accumulation in targeting organ and MPS organs, respectively.

Radiopharmaceutical evaluation of 131I-protohypericin as a necrosis avid compound

Abstract Hypericin is a necrosis avid agent useful for nuclear imaging and tumor therapy. Protohypericin, with a similar structure to hypericin except poorer planarity, is the precursor of hypericin. In this study, we aimed to investigate the impact of this structural difference on self-assembly, and evaluate the necrosis affinity and metabolism in the rat model of reperfused hepatic infarction. Protohypericin appeared less aggregative in solution compared with hypericin by fluorescence analysis. Biodistribution data of 131I-protohypericin showed the percentage of injected dose per gram of tissues (%ID/g) increased with time and reached to the maximum of 7.03 at 24 h in necrotic liver by gamma counting. The maximum ratio of target/non-target tissues was 11.7-fold in necrotic liver at 72 h. Pharmacokinetic parameters revealed that the half-life of 131I-protohypericin was 14.9 h, enabling a long blood circulation and constant retention in necrotic regions. SPECT-CT, autoradiography, and histological staining showed high uptake of 131I-protohypericin in necrotic tissues. These results suggest that 131I-protohypericin is a promising necrosis avid compound with a weaker aggregation tendency compared with hypericin and it may have a broad application in imaging and oncotherapy.

Discovery of radioiodinated monomeric anthraquinones as a novel class of necrosis avid agents for early imaging of necrotic myocardium

Assessment of myocardial viability is deemed necessary to aid in clinical decision making whether to recommend revascularization therapy for patients with myocardial infarction (MI). Dianthraquinones such as hypericin (Hyp) selectively accumulate in necrotic myocardium, but were unsuitable for early imaging after administration to assess myocardial viability. Since dianthraquinones can be composed by coupling two molecules of monomeric anthraquinone and the active center can be found by splitting chemical structure, we propose that monomeric anthraquinones may be effective functional groups for necrosis targetability. In this study, eight radioiodinated monomeric anthraquinones were evaluated as novel necrosis avid agents (NAAs) for imaging of necrotic myocardium. All 131I-anthraquinones showed high affinity to necrotic tissues and 131I-rhein emerged as the most promising compound. Infarcts were visualized on SPECT/CT images at 6 h after injection of 131I-rhein, which was earlier than that with 131I-Hyp. Moreover, 131I-rhein showed satisfactory heart-to-blood, heart-to-liver and heart-to-lung ratios for obtaining images of good diagnostic quality. 131I-rhein was a more promising “hot spot imaging” tracer for earlier visualization of necrotic myocardium than 131I-Hyp, which supported further development of radiopharmaceuticals based on rhein for SPECT/CT (123I and 99mTc) or PET/CT imaging (18F and 124I) of myocardial necrosis.

Cyclocarya paliurus prevents high fat diet induced hyperlipidemia and obesity in Sprague–Dawley rats

Cyclocarya paliurus (CP; qing qian liu), which is used as an herbal tea in China, has been confirmed to have therapeutic effects on hyperlipidemia and obesity, and therefore it is widely consumed to prevent metabolic diseases such as hyperlipidemia and diabetes. In this study, we investigated the preventive effects of CP on obesity and hyperlipidemia, as well as the underlying mechanisms involved in intestinal secretion of apolipoprotein (apo) B48. Sprague-Dawley rats were fed a high-fat diet (HFD) and with or without various concentrations of an ethanol extract of CP (CPE; 2, 4, or 8 g·(kg body mass)(-1)) administered by gavage for 8 weeks. From the results we see that CPE dose-dependently blocked increases in body mass, and decreased food utilization as well as visceral fat mass. Decreased serum levels of total cholesterol, triglycerides, and low density lipoprotein cholesterol, and elevated levels of high density lipoprotein cholesterol, as well as lowered levels of total cholesterol and triglycerides in the liver were also noticed in CPE-treated rats. Magnetic resonance images indicated that the abnormal fat storage induced by the HFD was obviously suppressed by CPE. In addition, ELISA analysis showed reduced fasting serum apoB48 in the CPE treatment groups. Based on the above results, CPE shows a promising preventive effect on obesity and hyperlipidemia, partially through suppressing intestinal apoB48 overproduction.

Chemical Fingerprint and Multicomponent Quantitative Analysis for the Quality Evaluation of Cyclocarya paliurus Leaves by HPLC–Q–TOF–MS

Cyclocarya paliurus is an edible and medicinal plant containing various bioactive components with significant health benefits. A combinative method using high-performance liquid chromatography (HPLC) fingerprint and quantitative analysis was developed and successfully applied for characterization and quality evaluation of C. paliurus leaves collected from 18 geographical locations of China. For the fingerprint analysis, 21 common peaks were observed among the 18 samples, and these peaks were identified by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC–Q–TOF–MS), while a simultaneous quantification of 16 markers was conducted to interpret the variations of contents of these bioactive compounds among the C. paliurus leaves from different geographical locations. Quantification results showed that the contents of these sixteen investigated compounds varied greatly among the leaves from different locations. The developed new method would be a valuable reference for further study and development of this bioactive plant.

Synthesis and preclinical evaluation of radioiodinated hypericin dicarboxylic acid as a necrosis avid agent in rat models of induced hepatic, muscular and myocardial necroses

Myocardial infarction (MI) leads to substantial morbidity and mortality around the world. Accurate assessment of myocardial viability is essential to assist therapies and improve patient outcomes. (131)I-hypericin dicarboxylic acid ((131)I-HDA) was synthesized and evaluated as a potential diagnostic agent for earlier assessment of myocardium viability compared to its preceding counterpart (131)I-hypericin ((131)I-Hyp) with strong hydrophobic property, long plasma half-life, and high uptake in mononuclear phagocyte system (MPS). Herein, HDA was synthesized and characterized, and self-aggregation constant Kα was analyzed by spectrophotometry. Plasma half-life was determined in healthy rats by γ-counting. (131)I-HDA and (131)I-Hyp were prepared with iodogen as oxidant. In vitro necrosis avidity of (131)I-HDA and (131)I-Hyp was evaluated in necrotic cells induced by hyperthermia. Biodistribution was determined in rat models of induced necrosis using γ-counting, autoradiography, and histopathology. Earlier imaging of necrotic myocardium to assess myocardial viability was performed in rat models of reperfused myocardium infarction using single photon emission computed tomography/computed tomography (SPECT/CT). As a result, the self-aggregation constant Kα of HDA was lower than that of Hyp (105602 vs 194644, p < 0.01). (131)I-HDA displayed a shorter blood half-life compared with (131)I-Hyp (9.21 vs 31.20 h, p < 0.01). The necrotic-viable ratio in cells was higher with (131)I-HDA relative to that with (131)I-Hyp (5.48 vs 4.63, p < 0.05). (131)I-HDA showed a higher necrotic-viable myocardium ratio (7.32 vs 3.20, p < 0.01), necrotic myocardium-blood ratio (3.34 vs 1.74, p < 0.05), and necrotic myocardium-lung ratio (3.09 vs 0.61, p < 0.01) compared with (131)I-Hyp. (131)I-HDA achieved imaging of necrotic myocardium at 6 h postinjection (p.i.) with SPECT/CT, earlier than what (131)I-Hyp did. Therefore, (131)I-HDA may serve as a promising necrosis-avid diagnostic agent for earlier imaging of necrotic myocardium compared with (131)I-Hyp. This may support further development of radiopharmaceuticals ((123)I and (99m)Tc) based on HDA for SPECT/CT of necrotic myocardium.

Effects of skeleton structure on necrosis targeting and clearance properties of radioiodinated dianthrones

Abstract Necrosis avid agents (NAAs) can be used for diagnose of necrosis-related diseases, evaluation of therapeutic responses and targeted therapeutics of tumor. In order to probe into the effects of molecular skeleton structure on necrosis targeting and clearance properties of radioiodinated dianthrones, four dianthrone compounds with the same substituents but different skeletal structures, namely Hypericin (Hyp), protohypericin (ProHyp), emodin dianthrone mesomer (ED-1) and emodin dianthrone raceme (ED-2) were synthesized and radioiodinated. Then radioiodinated dianthrones were evaluated in vitro for their necrosis avidity in A549 lung cancer cells untreated and treated with H2O2. Their biodistribution and pharmacokinetic properties were determined in rat models of induced necrosis. In vitro cell assay revealed that destruction of rigid skeleton structure dramatically reduced their necrosis targeting ability. Animal studies demonstrated that destruction of rigid skeleton structure dramatically reduced the necrotic tissue uptake and speed up the clearance from the most normal tissues for the studied compounds. Among these 131I-dianthrones, 131I-Hyp exhibited the highest uptake and persistent retention in necrotic tissues. Hepatic infarction could be clearly visualized by SPECT/CT using 131I-Hyp as an imaging probe. The results suggest that the skeleton structure of Hyp is the lead structure for further structure optimization of this class of NAAs.

Experimental evaluation of radioiodinated sennoside B as a necrosis-avid tracer agent.

Abstract Necrosis-avid agents are a class of compounds that selectively accumulate in the necrotic tissues after systemic administration, which can be used for in vivo necrosis imaging and targeted therapies. In order to search for a necrosis-avid tracer agent with improved drugability, we labelled iodine-131 on sennoside B (SB) as a naturally occurring median dianthrone compound. The necrosis targetability and clearance properties of 131I-SB were evaluated in model rats with liver and muscle necrosis. On SPECT/CT images, a “hot spot” in the infarcted liver lobe and necrotic muscle was persistently observed at 24 h and 72 h post-injection (p.i.). Gamma counting of the tissues of interest revealed a radioactivity ratio of necrotic to viable liver at 4.6 and 3.4 and of necrotic to viable muscle at 7.0 and 8.8 at 24 h and 72 h p.i., respectively. The good match of autoradiographs and fluoromicroscopic images with corresponding histochemical staining suggested preferential uptake of 131I-SB in necrotic tissue. Pharmacokinetic study revealed that 131I-SB has an elimination half-life of 8.6 h. This study indicates that 131I-SB shows not only prominent necrosis avidity but also favourable pharmacokinetics, which may serve as a potential necrosis-avid diagnostic agent for assessment of tissue viability.