Guoqing Gong

Antifibrotic activity of galangin, a novel function evaluated in animal liver fibrosis model.

This study aimed to investigate the effects of galangin on liver fibrosis in rats induced by subcutaneous injection of carbon tetrachloride (CCl4). The administration of CCl4 to rats for 12 weeks caused significant increase of hyaluronic acid, laminin, alanine transaminase, aspartate transaminase and decrease of total protein, albumin in serum, while the influences could be reversed by galangin. Galangin markedly reduced hepatic malondialdehyde, hydroxyproline concentration, increased activities of liver superoxide dismutase, glutathione peroxidase compared with CCl4-treated rats. Histological results indicated that galangin alleviated liver damage. In addition, treatment with galangin significantly down-regulated expressions of α-smooth muscle actin and transforming growth factor β1. These results suggest galangin can inhibit liver fibrosis induced by CCl4 in rats, which was probably associated with its effect on removing oxygen free radicals, decreasing lipid peroxidation, as well as inhibiting hepatic stellate cells activation and proliferation.

Design, synthesis and antithrombotic evaluation of novel dabigatran prodrugs containing methyl ferulate

A novel series of prodrugs containing dabigatran and methyl (E)-3-(4-hydroxy-2-methoxyphenyl)propenoate (methyl ferulate) were synthesized. All of them reveal the effect of thrombin-induced anti-platelet aggregation in vitro. In addition, in vivo experiment shows that one of the target compounds, X-2 (ED50=3.7 ± 1.0 μmol/kg) possesses a more potent activity for inhibiting venous thrombosis than that of dabigatran etexilate (ED50=7.8 ± 1.5 μmol/kg).

Synthesis and antithrombotic evaluation of novel dabigatran prodrugs containing a cleavable moiety with anti-platelet activity.

A novel series of prodrugs consisting of dabigatran and 2-hydroxymethyl-3,5,6-trimethylpyrazine (HTMP) were synthesized. The pharmacological results show that all of them possess the effect of anti-platelet aggregation induced by thrombin in vitro. Moreover, one of those compounds, Y-2 (ED(50) = 2.1 ± 1.3 mg/kg) shows more potent activity for inhibiting thrombosis in vivo than that of dabigatran etexilate (ED(50) = 4.4 ± 2.2 mg/kg).

Antidepressant-like effect of evodiamine on chronic unpredictable mild stress rats.

Evodiamine is a major alkaloid compound extracted from the dry unripened fruit Evodia fructus (Evodia rutaecarpa Benth., Rutaceae), which has a variety of pharmacological activities. The present study aims to determine the antidepressant-like effect of evodiamine in a rat model of chronic unpredictable mild stress (CUMS). We identified that evodiamine could reverse the following CUMS-induced behavioural deficits and biochemical changes in rats: the decreases of sucrose preference, number of crossings, 5-HT and NA levels, as well as the increase of immobility time. Evodiamine treatments also ameliorated the corticosterone hypersecretion induced by CUMS. Furthermore, we found that evodiamine was able to up-regulate the expression of brain-derived neurotrophic factor (BDNF) and phosphorylated tropomyosin-related kinase B (pTrkB) without altering TrkB. This study suggests potential antidepressant-like effect of evodiamine on CUMS rats, and its underlying mechanisms can be potentially linked to their modulating effects on the monoamine transmitters and BDNF-TrkB signaling in the hippocampus.

Antithrombotic activity of HY023016, a novel Dabigatran prodrug evaluated in animal thrombosis models

INTRODUCTION Thrombin is a multifunctional trypsin-like serine protease that plays key roles in coagulation and thrombogenesis. HY023016, a novel Dabigatran prodrug, is an oral direct thrombin inhibitor. The purpose of this study was to compare the anti-thrombotic activities and haemorrhagic effects of HY023016 with Dabigatran etexilate and tetramethylpyrazine in several animal thrombosis models. METHODS To investigate drug exposure, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to determine the pharmacokinetic profile of HY023016. After single intragastric administrations of HY023016, Dabigatran etexilate or tetramethylpyrazine, the anti-thrombotic activities were evaluated through rabbit jugular vein thrombosis model, rat inferior vena cava thrombosis model, ex vivo rabbit platelet aggregation assay, in vivo rabbit coagulation assay, and direct thrombin binding assay. Meanwhile, we evaluated the effect of HY023016 on expression of tissue factor (TF) by RT-PCR. Rabbit cuticle bleeding assay and mouse tail bleeding assay were applied to evaluate the effects of HY023016 on haemorrhage. RESULTS Pharmacokinetic parameters indicated that HY023016 can convert to Dabigatran and tetramethylpyrazine. Our studies showed that HY023016 was able to significantly inhibit thrombus formation in a dose-dependent manner in rabbit and rat models (P<0.05). Similarly, it was able to dose-dependently inhibit thrombin- or ADP-induced platelet aggregation, prolonging the activated partial thromboplastin time (APTT) and prothrombin time (PT), inhibiting the activity of thrombin and inhibiting thrombin- or ADP-induced expression of TF (P<0.05 or 0.01). Dabigatran etexilate was also able to dose-dependently and significantly inhibit thrombus formation (P<0.01) but was unable to affect ADP-induced platelet aggregation and expression of TF. In contrast, tetramethylpyrazine could only exhibit mild antithrombotic activity compared with HY023016 and Dabigatran etexilate (P<0.05). HY023016 could prolong bleeding time (P<0.001), but the prolongations were significantly less than Dabigatran etexilate (P<0.05). CONCLUSION HY023016 showed thrombosis-inhibition activities comparable to those of Dabigatran etexilate, but better than those of tetramethylpyrazine. The attendant bleeding risk of HY023016 was lower than Dabigatran etexilate in rabbits and mice.

Discovery and SAR study of 2-(1-propylpiperidin-4-yl)-3H-imidazo[4,5-c]pyridine-7-carboxamide: A potent inhibitor of poly(ADP-ribose) polymerase-1 (PARP-1) for the treatment of cancer.

A series of imidazo[4,5-c]pyridine-7-carboxamide derivatives as poly(ADP-ribose) polymerase (PARP) inhibitors have been developed. All target compounds were evaluated for their PARP-1 inhibitory activity and some were further assessed for cellular potency. These efforts led to identification of a novel PARP-1 inhibitor 2-(1-propylpiperidin-4-yl)-3H-imidazo[4,5-c]pyridine-7-carboxamide 11a (XZ-120312). 11a displayed strong inhibition against the PARP-1 enzyme with an IC50 of 8.6±0.6 nM and excellent potentiation of temozolomide cytotoxicity in cancer cell lines SW-620, MDA-MB-468 and A549 by 4.0, 3.0 and 7.7 times, respectively.

Synthesis and pharmacological evaluation of novel limonin derivatives as anti-inflammatory and analgesic agents with high water solubility

A novel series of water-soluble derivatives of limonin were synthesized by introducing various tertiary amines onto the C (7)-position of limonin. Ten target compounds were characterized and screened for their anti-inflammatory and analgesic activity in vivo. Compound 3c exhibited the strongest analgesic and anti-inflammatory activity among the limonin and its derivatives tested; its analgesic activity is more potent than that of aspirin and its anti-inflammatory activity is stronger than that of naproxen.

Design, synthesis and antithrombotic evaluation of novel dabigatran etexilate analogs, a new series of non-peptides thrombin inhibitors.

Thrombin is a serine protease that plays a key role in blood clotting, which makes it a promising target for the treatment of thrombotic diseases. Dabigatran is direct potent thrombin inhibitor. Based on bioisosteric and scaffold hopping principle, two dabigatran mimics (I-1 and II-1) in which the benzamidine moiety of dabigatran was replaced by a tricyclic fused scaffold were designed, synthesized and evaluated for their in vitro activities for inhibiting thrombin. The results reveal that compounds I-1 (IC50=9.20nM) and II-1 (IC50=7.48nM) are potent direct thrombin inhibitors and the activity is in the range of reference drug. On this basis, twenty-two ester and carbamate derivatives of I-1 or II-1 were prepared and evaluated for their anticoagulant activity. Prodrugs I-4a (IC50=0.73μM), I-4b (IC50=0.75μM), II-2a (IC50=1.44μM) and II-2b (IC50=0.91μM) display excellent effects of inhibiting thrombin induced-platelet aggregation. Moreover, compounds I-9 and II-4, which contain a cleavable moiety with anti-platelet activity, show the best anticoagulant efficacy among the tested compounds in the rat venous thrombosis model. The compounds which have better in vitro and in vivo activity were subjected to rat tail bleeding test, and the result demonstrates that compound I-9 is less likely to have bleeding risk than dabigatran etexilate.

Design, Synthesis, and Biological Evaluation of Dabigatran Etexilate Mimics, a Novel Class of Thrombin Inhibitors.

Human α‐thrombin is a particularly promising target for anticoagulant therapy, and identification of oral small‐molecular inhibitors of thrombin remains a research focus. On the basis of the X‐ray crystal structure of human α‐thrombin and its inhibitor dabigatran, we designed and synthesized a series of dabigatran etexilate mimics containing a novel tricyclic fused scaffold. The biological evaluations reveal that all of the compounds possess moderate activity of antiplatelet aggregation induced by thrombin in vitro. Moreover, compound I‐8, which contains 2‐hydroxymethyl‐3,5,6‐trimethylpyrazine (HTMP), a cleavable moiety with antiplatelet activity, shows the best anticoagulant effect among the tested compounds in vivo. Those synthesized compounds that have better in vitro activity were subjected to bleeding complication tests, and the results demonstrate that the novel compounds are less likely to have bleeding risk than dabigatran etexilate.

The cardioprotective effect of TG-6, a newly synthesized compound, on ischemia-reperfusion injury in rats.

We tested 3-nitro-4-((4-(2,3,4-trimethoxybenzyl)piperazin-1-yl)methyl) benzoylguanidine tartrate (TG-6) which is combinated of two known cardioprotective agents cariporide and trimetazidine, whether additively to reduce ischemia-reperfusion injury in rats. Using models of in vitro perfusion (Langendorff system) and in vivo open chest left anterior descending coronary artery ligation causing ischemia-reperfusion injury. We also used Fura-2 to measure the cytosolic Ca²⁺ concentrations ([Ca²⁺]i) in cardiomyocytes, western blot analysis the protein expression of Kv1.4, Kv4.2, Kv4.3 in myocardial ischemia-reperfusion rats. TG-6 improved the cardiac function in both in vivo and in vitro models, lowered Lactate Dehydrogenase (LDH), Creatine Kinase (CK), Malodialdehyed (MDA) activity while enhanced Superoxide Dismutase (SOD) activity. High dose of TG-6 improved the hypoxia injury of cardiomyocytes induced by sodium dithionite (Na₂S₂O₄), enhanced the viability and decreased the [Ca²⁺]i. It also down-regulated the expression of Kv1.4 and increased the expression of Kv4.2 and Kv4.3, so it might through regulating the expression of the transient outward potassium current (Ito) to improve the cardiac function.