Deciphering molecular mechanism underlying hypolipidemic activity of echinocystic Acid

Synthesis, biological activity, molecular docking studies of a novel series of 3-Aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives as the acetylcholinesterase inhibitors

The acetylcholinesterase inhibitors play a critical role in the drug therapy for Alzheimer's disease. In this study, twenty-nine novel 3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were synthesized and assayed for their human acetylcholinesterase (hAChE) inhibitory activities. Inhibitory ratio values of seventeen compounds were above 55% with 4c having the highest value as 77.19%. The compounds with the halogen atoms in the aromatic ring, and N,N-diethylamino or N,N-dimethylamino groups in the side chains at C-3 positions exhibited good inhibitory activity. SAR study was carried out by means of molecular docking technique. According to molecular docking results, the common interacting site for all compounds were found to be peripheral anionic site whereas highly active compounds were interacting with the catalytic active site too. HIGHLIGHTSA novel series of 3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives were synthesized and assayed for their human acetylcholinesterase (hAChE) inhibitory activities.The SAR study of the target 3-aryl-7H-thiazolo[3,2-b]-1,2,4-triazin-7-one derivatives was summarized.The active sites in the acetylcholinesterase were analyzed by molecular docking technique.Communicated by Ramaswamy H. Sarma.

Echinocystic acid provides a neuroprotective effect via the PI3K/AKT pathway in intracerebral haemorrhage mice

Background

Echinocystic acid (EA), a natural extract from plants of Gleditsia sinensis Lam, exhibits anti-inflammatory, antioxidant and analgesic activities in different diseases. In this study, we explored the pharmacological effects of EA on intracerebral haemorrhage (ICH) in a collagenase-induced ICH mouse model.

Methods

EA (50 mg/kg, i.p. q.d) was injected after the establishment of ICH, and we measured the amount of degraded neurons in brain tissue with Fluoro-Jade C staining and the haemorrhagic injury volume with Luxol fast blue staining on day 3 after ICH. We also assessed animal behaviour by rotarod test, claw force test and modified neurological severity score (mNSS) score. The expression of apoptosis-related proteins such as Bcl-2, Bax and cleaved caspase-3 was analysed by Western blot.

Results

EA reduced both the death of neurons and the volume of haemorrhagic injury after ICH. The haemorrhage infarct volume of the ICH+EA group was 9.84%±3.32% lower than that in the ICH group of mice (P<0.01). The mNSS score of the ICH+EA treated group was 4.75±0.55 lower than that in the ICH group (P<0.01). With the administration of EA after ICH, the expression of Bcl-2 was upregulated while the Bax level was downregulated. The cleaved caspase-3 level was also significantly decreased. We further investigated the neuroprotective mechanism of EA. Western blot results showed that the expression of P-AKT increased after EA treatment and decreased after LY294002, an inhibitor of the PI3K/AKT pathway, treatment.

Conclusions

EA may provide neuroprotection via activation of the PI3K/AKT pathway. Given the safety of EA has been proven, further studies are required to investigate whether EA is a potential agent for the treatment of ICH.

Triterpenic acids-enriched fraction from Cyclocarya paliurus attenuates insulin resistance and hepatic steatosis via PI3K/Akt/GSK3β pathway

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver diseases. Cyclocarya paliurus (C. paliurus), an edible and medicinal plant in Chinese folk, has been demonstrated to ameliorate diabetes, obesity and lipid metabolism disorders. However, its effects on NAFLD and its potential molecular mechanism have not been clearly expounded.

PURPOSE

The present study was designed to explore the therapeutic potential of triterpenic acids-enriched fraction from C. paliurus (CPT), as well as its underlying mechanism in vivo and in vitro models of NAFLD.

METHODS

The metabolic effects and possible molecular mechanism of CPT were examined using HepG2 cells and primary hepatocytes (isolated from C57BL/6 J mice) models of fatty liver induced by palmitic acid (PA) and a high fat diet mouse model.

RESULTS

In high fat diet-induced C57BL/6 J mice, CPT significantly reduced liver weight index, serum alanine transaminase (ALT), aspartate transaminase (AST), triacylglycerol (TG), total cholesterol (TC) and hepatic TG, TC levels. Moreover, CPT dramatically decreased the contents of blood glucose, insulin, and insulin resistance (HOMA-IR) index. Meanwhile, CPT significantly increased the tyrosine phosphorylation level of IRS and the uptake of 2-deoxyglucose (2DG) in PA-induced HepG2 cells and primary hepatocytes fatty liver models. Furthermore, in PA-induced HepG2 cells and primary hepatocytes, CPT significantly decreased the number of lipid droplets and intracellular TG content. In addition, mechanism investigation showed that CPT increased the phosphorylation of phosphoinositide 3-kinase (PI3K), protein kinase B (Akt) and glycogen synthase-3β (GSK3β) in vivo and in vitro models, which were abrogated by PI3K inhibitor LY294002 in vitro models.

CONCLUSION

These findings indicate that CPT may exert the therapeutic effects on NAFLD via regulating PI3K/Akt/GSK3β pathway.

Echinocystic acid, a natural plant extract, alleviates cerebral ischemia/reperfusion injury via inhibiting the JNK signaling pathway

Echinocystic acid (EA) was found to possess antiviral, anti-inflammatory and antioxidation activities. A recent study showed the antiapoptotic effects of EA on acute myocardial infarction. In this study, we demonstrated the potential neuroprotective effects of EA on cerebral ischemia/reperfusion (I/R) injury in mice. Intraperitoneal injection of EA 1 h before ischemia significantly reduced the cerebral infarct volume and neurological deficit after 60 min of ischemia and 24 h of reperfusion. The neuroprotective effects of EA occurred in a dose-dependent manner. Then, we explored the mechanisms of neuroprotection by EA. This compound exerted antiapoptotic activity by upregulating the level of Bcl-2 and simultaneously downregulating the levels of cleaved caspase-3 and Bax. Furthermore, EA also possessed anti-inflammatory activity and prevented the excessive phosphorylation of NF-κB (p-P65) and the increase in IL-1β and IL-6 levels. Finally, our data indicated that EA treatment decreased the level of phosphorylated JNK in vivo, and the JNK activator anisomycin (AN) reversed the neuroprotective effects of EA, indicating that the JNK pathway is involved in the antiapoptotic and anti-inflammatory mechanisms of EA. In summary, our findings suggest that EA provides neuroprotective effects through its antiapoptotic and anti-inflammatory activities by inhibiting the JNK signaling pathway in cerebral I/R injury. Due to its safety and lack of toxicity, EA is a potential candidate for the treatment of ischemic stroke in future clinical trials.

Antihyperlipidaemic effect of triterpenic acid-enriched fraction from Cyclocarya paliurus leaves in hyperlipidaemic rats

CONTEXT

Cyclocarya paliurus (Batal) Iljinskaja (Juglandaceae) is an edible and medicinal plant; the leaves are used in Chinese folkloric medicine to treat dyslipidaemia and diabetes.

OBJECTIVE

This study evaluates the antihyperlipidaemic potential of the triterpenic acid-enriched fraction (TAE) from C. paliurus and the underlying mechanism.

MATERIALS AND METHODS

The hyperlipidaemic rats were induced by high fat diet for 6 weeks. After oral administration of TAE (200 and 400 mg/kg), the neutral fraction (150 and 300 mg/kg) and statin (4 mg/kg) to the hyperlipidaemic rats for 4 weeks, lipid profile and apolipoprotein (apoB48) level in plasma, and the expression levels of apoB48, microsomal triglyceride transfer protein (MTP), phosphorylation of mitogen-activated protein kinase (MAPK) and tumour necrosis factor α (TNF-α) in intestine were examined. The main constituents in the TAE were identified by HPLC-MS.

RESULTS

TAE administration (400 mg/kg) decreased the levels of atherogenic lipids in serum and liver (p < 0.05) and increased serum high-density lipoprotein cholesterol by 19.7%. Furthermore, TAE treatment (200 and 400 mg/kg) decreased plasma apoB48 level by 15.3 and 19.5%, downregulated intestinal apoB48 and MTP expression levels (p < 0.05), and inhibited TNF-α expression by 36.2 and 56.2% and the phosphorylation level of MAPK by 8.8 and 13.2%, respectively. HPLC analysis revealed the presence of pentacyclic- and tetracyclic-triterpene acids in TAE.

CONCLUSION AND DISCUSSION

These findings suggested that TAE possessed antihyperlipidaemic activity partially involved in the inhibitory effect on apoB48 overproduction, which may provide evidence about its potential role in ameliorating dyslipidaemia.

Inhibitory effects on the HMG-CoA Reductase in the chemical constituents of the Cassia mimosoides Linn

Cassia mimosoides Linn has been used from ancient times and used for treating hepatitis for its supposedly medically beneficial properties. In this study, different constituents of the Cassia mimosoides Linn (β-Sitosterol, Oleanolic Acid, Emodin, Carotene, Resorcinol, Luteolin, and α-L-Rhamnose) were evaluated for potential anti-HMG-CoA reductase effect. The inhibitory effects of HMG-CoA reductase of Cassia mimosoides Linn extracts and Pravastatin inhibitor at different concentrations (at doses of 1, 5, 25 or 125 μg/mL, respectively) in reaction system (70 mmol/L phosphate buffer, 200mmol/L NADPH, 5 μg HMG-CoA reductase, 2 mmol/L EDTA, 2 mmol/L cysteamine, 0.06% BSA) into 37°C preheat HMG-CoA for initiating this reaction, and then determined the change of HMG-CoA reductase activity (ΔAΔt) at 340 nm, the inhibition ratio of HMG-CoA reductase activity and its dynamic change of inhibitory effect within 15 min and the descent rate of NADPH. Emodin, Luteolin, β-Sitosterol, Oleanolic Acid, α-L-Rhamnose and Carotene showed good inhibition of HMG-CoA reductase activity. Among them, only the Emodin (1 and 5 μg/mL) groups showed a significant decrease of HMG-CoA reductase activity compared to the Pravastatin (1 and 5 μg/mL) groups respectively. In addition, the HMG-CoA reductase activity in the Emodin and Luteolin (25 and 125 μg/mL) groups was clearly lower than the Pravastatin (25 and 125 μg/mL) groups respectively. And the Emodin and Luteolin (1, 5, 25 or 125 μg/mL) groups exhibited a stable effect on inhibiting the HMG-CoA reductase within 15 min. These findings further support the exploration of Cassia mimosoides Linn as a potential agent for the treatment of hepatitis in future studies.