Antidepressant polyprenylated acylphloroglucinols from Hypericum ascyron.

Phytochemical investigation on the 90% EtOH extract of the air-dried aerial parts of Hypericum ascyron resulted in the isolation of three new polycyclic polyprenylated derivatives ascyronines A-C (1-3). Structural elucidation of all the compounds was performed by spectral methods such as 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy. All the polycyclic polyprenylated acylphloroglucinols were evaluated for their antidepressant activity by inhibiting the reuptake of tritiated serotonin ([3H]-5-HT) and noradrenalinet ([3H]-NE) in rat brain synaptosomes. Compounds 2 and 3 exhibited weak antidepressant activities in the [3H]-5-HT mode.

A covalent organic framework nanosheet-based electrochemical aptasensor with sensitive detection performance.

The development of covalent organic framework nanosheet (COF NS) is becoming a vitally important research field by reason of its high permeability, ordered structure, high utilization of functional site, favourable dispersability and large aspect ratio, resulting in their widespread applications in separation, catalysis, sensing and optical device. In this work, a Tp-Bpy COF NS was prepared via an interfacial synthesis of 2,4,6-triformylphloroglucinol (Tp) and 5,5'-diamino-2,2'-bipyridine (Bpy), which has film morphology, high surface area, large pore, excellent stability and various functional site. It was utilized as a functional material to immobilize aptamers for constructing a sensitive electrochemical aptasensor. Compared with bulk Tp-Bpy COF, Tp-Bpy COF NS can significantly enhance the biosensing performance toward ultra-trace tobramycin. This work is benefit for the exploration of COF NSs and their electrochemical aptasensors in biosensing applications.

Antimicrobial ent-abietane-type diterpenoids from the roots of Euphorbia wallichii.

Three previously undescribed ent-abietane-type diterpenoids, designated as 11ß-hydroxy-14-oxo-17-al-ent-abieta-8(9),13(15)-dien-16,12ß-olide (1), 11ß,17-dihydroxy-12-methoxy-ent-abieta-8(14),13(15)-dien-16,12ɑ-olide (2), and 14ɑ-hydroxy-17-al-ent-abieta-7(8),11(12),13(15)-trien-16,12-olide (3), were isolated from 95% ethanol extract of the roots of Euphorbia wallichii. The structures of the new compounds were elucidated by spectroscopic analysis (NMR, IR, UV, and MS). The isolated diterpenoids were tested in vitro for antimicrobial potentials against 6 pathogenic microorganisms. As a result, compounds 1-3 exhibited some antimicrobial activity against the tested Gram positive bacteria with minimum inhibitory concentration values less than 60 µg/ml.[Formula: see text].

Functional divergence of flagellar type III secretion system: A case study in a non-flagellated, predatory bacterium.

The lack of functional flagella and the ability to prey upon other microorganisms are well-known traits of Lysobacter enzymogenes, a plant beneficial bacterial species. Here, we report a possible link between these two traits in the model strain L. enzymogenes OH11 (OH11). The genome of OH11 encompasses several homologous genes involved in the flagellum formation but it lacks a functional fliC, encoding the flagellin. Despite the lack of the main component of the flagellum, OH11 genome includes genes involved in the flagellar type III secretion system (FT3SS), which is commonly deployed by flagellated bacteria to transport flagellar subunit proteins. To understand the role played by FT3SS in OH11, we showed that the remaining FT3SS genes were expressed under laboratory conditions. Subsequently, we showed that the identified FT3SS genes involved in the secretion of the hook-capping protein FlgD, suggesting OH11 likely possessed a functional FT3SS system. Blocking FT3SS in OH11 via inactivation of the ATPase FliI impaired the secretion of the proteins Le3970 (protease), Le4493 (ß-1,3-glucanase A) and Le1659 (halo acid dehalogenase family), that showed a toxic activity against the yeast Saccharomyces cerevisiae. The possible link between FT3SS and OH11 antagonism towards S. cerevisiae was also confirmed by loss of toxicity in both mutants of ΔfliI and ΔflhB that lacks the FT3SS structural gene flhB when co-cultured with the yeast strain. The design of synthetic proteins toxic against the Gram-negative bacterium Ralstonia solanacearum further supported the involvement of FT3SS in the ability of OH11 to parasitize other microorganisms. Overall, these results revealed a possible cooption of components of FT3SS system in the competition with other microorganisms in the plant beneficial bacterium OH11 and highlighted a functional divergence of FT3SS between flagellated and non-flagellated bacteria.

Baroreflex deficiency aggravates atherosclerosis via α7 nicotinic acetylcholine receptor in mice.

OBJECTIVE: Inflammation and oxidative stress play a key role in the initiation, propagation, and development of atherosclerosis. Arterial baroreflex (ABR) dysfunction induced by sinoaortic denervation (SAD) promoted the development of atherosclerosis in ApoE-/- mice. The present work was designed to examine whether ABR deficiency affected inflammation and oxidative stress via α7 nicotinic acetylcholine receptor (α7nAChR) leading to the aggravation of atherosclerosis in mice. METHODS AND RESULTS: ApoE-/- mice were fed with a high-cholesterol diet for 6weeks and half of the mice received sinoaortic denervation that destroyed ABR. We studied the expression of vesicular acetylcholine transporter (VAChT), α7nAChR and levels of inflammatory response and oxidative stress. The results showed that baroreflex dysfunction could promote atherosclerosis, meanwhile, decrease the expression of VAChT and α7nAChR and significantly increase the levels of oxidative stress and inflammation in SAD mice. After treated with PNU-282987 (a selective α7nAChR agonist, 0.53mg/kg/day) for 6weeks in SAD and Sham mice, we found that PNU-282987 could attenuate atherosclerosis and significantly decreased oxidative stress and inflammation after SAD. In addition, α7nAChR+/+ and α7nAChR-/- mice fed with a high-cholesterol diet for 8weeks were co-treated with ketanserin (0.6mg/kg/day), a drug that can enhance baroreflex sensitivity (BRS). Ketanserin could alleviate atherosclerosis and markedly decrease oxidative stress and inflammation in α7nAChR+/+ mice. But there were no effects in α7nAChR knockout mice. CONCLUSIONS: Our results demonstrate that ABR dysfunction aggravates atherosclerosis in mice via the vagus-ACh-α7nAChR-inflammation and oxidative stress pathway.

Diurnal Variation of the Peripheral Cholinergic Antiinflammatory Function in Mice.

AIMS: Cholinergic antiinflammatory (CAI) pathway functions importantly in inflammation via α7 nicotinic acetylcholine receptors (α7nAChR). The present work tested circadian rhythm in peripheral CAI activity and validities of CAI activity and glucocorticoids in chronotherapy for lipopolysaccharide (LPS)-induced shock. METHODS: Vesicular acetylcholine transporter (VAChT) expressed in liver and kidney was examined every 3 h in C57BL/6 mice. Proinflammatory cytokines in serum and survival time in shock were monitored after LPS injection every 3 h. Mifepristone, antagonist of glucocorticoid receptors, and methyllycaconitine (MLA), antagonist of α7nAChR, were administrated before LPS to block antiinflammatory function of endogenous glucocorticoids and acetylcholine. RESULTS: Both levels of tumor necrosis factor α, interleukin 1ß, and interleukin 6 and mortality exhibited diurnal variations with prominent peaks when LPS was given at 15:00, and the minimum mortality occurred at 00:00. Expression of VAChT increased during resting period. MLA increased serum proinflammatory cytokines slightly, but not affected survival rate. Both differences in cytokines and in survival times between LPS injection at 15:00 and 00:00 were eliminated by mifepristone, but not by MLA. CONCLUSION: Peripheral CAI pathway exerts more powerful antiinflammatory effect during resting period. Glucocorticoids appear to be efficient in chronotherapy for septic shock.

Activation of α7 Nicotinic Acetylcholine Receptor Decreases On-site Mortality in Crush Syndrome through Insulin Signaling-Na/K-ATPase Pathway.

On-site mortality in crush syndrome remains high due to lack of effective drugs based on definite diagnosis. Anisodamine (Ani) is widely used in China for treatment of shock, and activation of α7 nicotinic acetylcholine receptor (α7nAChR) mediates such antishock effect. The present work was designed to test whether activation of α7nAChR with Ani decreased mortality in crush syndrome shortly after decompression. Sprague-Dawley rats and C57BL/6 mice with crush syndrome were injected with Ani (20 mg/kg and 28 mg/kg respectively, i.p.) 30 min before decompression. Survival time, serum potassium, insulin, and glucose levels were observed shortly after decompression. Involvement of α7nAChR was verified with methyllycaconitine (selective α7nAChR antagonist) and PNU282987 (selective α7nAChR agonist), or in α7nAChR knockout mice. Effect of Ani was also appraised in C2C12 myotubes. Ani reduced mortality and serum potassium and enhanced insulin sensitivity shortly after decompression in animals with crush syndrome, and PNU282987 exerted similar effects. Such effects were counteracted by methyllycaconitine or in α7nAChR knockout mice. Mortality and serum potassium in rats with hyperkalemia were also reduced by Ani. Phosphorylation of Na/K-ATPase was enhanced by Ani in C2C12 myotubes. Inhibition of tyrosine kinase on insulin receptor, phosphoinositide 3-kinase, mammalian target of rapamycin, signal transducer and activator of transcription 3, and Na/K-ATPase counteracted the effect of Ani on extracellular potassium. These findings demonstrated that activation of α7nAChR could decrease on-site mortality in crush syndrome, at least in part based on the decline of serum potassium through insulin signaling-Na/K-ATPase pathway.

[Cloning and tissue expression of mevalonate disphosphate decarboxylase genes from Andrographis paniculata].

Andrographolide is a main bioactive substance in Andrographis paniculata, and extensively used in anti-inflammatory drugs. In order to increase andrographolide production in plant, three 1260 bp ORFs encoding mevalonate disphosphate decarboxylases with 419 amino acids were cloned from A. paniculata by RACE method and analyzed by bioinformatic software. Their tissue expression patterns were predicted by real time PCR. Eleven conserved amino acid residues determining specificity and activity of these MVDs were predicted in these amino acid sequences, but no plastid targeted signal peptides were detected. These MVDs have high similarities with the MVD protein (GenBank number: AEZ55675.1) from Salvia miltiorrhiza. In stems and leaves, expression levels of these MVD genes were constant, and reached the highest level at bud stage and the beginning of flowering. The MVD genes we have cloned from A. paniculata could be used in genetic engineering of andrographolide biosynthsis pathway in future.

Ketanserin improves cardiac performance after myocardial infarction in spontaneously hypertensive rats partially through restoration of baroreflex function.

AIM: Baroreflex dysfunction is associated with a higher rate of sudden death after myocardial infarction (MI). Ketanserin enhances baroreflex function in rats. The present work was designed to examine whether ketanserin improves the post-MI cardiac function and to explore the possible mechanism involved. METHODS: Spontaneously hypertensive rats (SHR) were treated with ketanserin (0.3 mg·kg(-1)·d(-1)). Two weeks later, blood pressure and baroreflex function were measured, followed by a ligation of the left coronary artery. The expressions of vesicular acetylcholine transporter (VAChT) and α7 nicotinic acetylcholine receptor (α7-nAChR) in ischemic myocardium, angiogenesis, cardiac function, and left ventricular (LV) remodeling were evaluated subsequently. RESULTS: Ketanserin significantly improved baroreflex sensitivity (0.62±0.21 vs 0.34±0.12 ms/mmHg, P<0.01) and vagal tonic activity (heart rate changes in response to atropine, 54.8±16.2 vs 37.6±13.4 bpm, P<0.01) without affecting the blood pressure or basic heart rate in SHR. Treatment of SHR with ketanserin prominently improved cardiac function and alleviated LV remodeling, as reflected by increases in the ejection fraction, fractional shortening, and LV systolic pressure as well as decreases in LV internal diameter and LV relative weight. The capillary density, vascular endothelial growth factor expression, and blood flow in the ischemic myocardium were significantly higher in the ketanserin-treated group. In addition, ketanserin markedly increased the expression of VAChT and α7-nAChR in ischemic myocardium. CONCLUSION: Ketanserin improved post-MI cardiac function and angiogenesis in ischemic myocardium. The findings provide a mechanistic basis for restoring baroreflex function using ketanserin in the treatment of MI.

An update on antitumor activity of naturally occurring chalcones.

Chalcones, which have characteristic 1,3-diaryl-2-propen-1-one skeleton, are mainly produced in roots, rhizomes, heartwood, leaves, and seeds of genera Angelica, Sophora, Glycyrrhiza, Humulus, Scutellaria, Parartocarpus, Ficus, Dorstenia, Morus, Artocarpus, and so forth. They have become of interest in the research and development of natural antitumor agents over the past decades due to their broad range of mechanisms including anti-initiation, induction of apoptosis, antiproliferation, antimetastasis, antiangiogenesis, and so forth. This review summarizes the studies on the antitumor activity of naturally occurring chalcones and their underlying mechanisms in detail during the past decades.