Evaluation of anti‐angiogenic,anti‐inflammatory and antinociceptive activity of coenzyme Q10 in experimental animals

Objectives This work aimed to assess some pharmacological activities of coenzyme Q₁₀ (CoQ₁₀) in animal experimental models. Methods The chick chorioallantoic membrane assay was used to evaluate anti‐angiogenic activity of CoQ₁₀. Anti‐inflammatory activity of CoQ₁₀ was confirmed using two animal models of inflammation. These were the vascular permeability and air pouch models, models of acute and sub‐acute inflammation, respectively. Antinociceptive activity was assessed by the acetic acid‐induced abdominal constriction response. Key findings CoQ₁₀ dose‐dependently displayed inhibition of chick chorioallantoic membrane angiogenesis. In the acetic acid‐induced vascular permeability model in mice, CoQ₁₀ at 50, 100 and 200 mg/kg reduced vascular permeability from 0.74 ± 0.01 (A₅₉₀) to 0.67 ± 0.01 (P < 0.01), 0.46 ± 0.02 (P < 0.01) and 0.30 ± 0.01 (P < 0.01), respectively. In the carrageenan‐induced inflammation in the air pouch, CoQ₁₀ was able to diminish exudate volume, the number of polymorphonulcear leucocytes and nitrite content in the air pouches. CoQ₁₀ at 25, 50 and 100 mg/kg significantly reduced acetic acid‐induced abdominal constriction in mice from 27.0 ± 2.00 (number of abdominal constrictions) to 17.7 ± 0.33 (P < 0.01), 9.3 ± 0.67 (P < 0.01) and 1.3 ± 0.33 (P < 0.01), respectively, suggesting a strong antinociceptive activity. Conclusions CoQ₁₀ possessed considerable anti‐angiogenic, anti‐inflammatory and antinociceptive activity, possibly via down‐regulating the level of nitric oxide, which partly supported its use as a dietary supplement and in combination therapy.     

Synthesis of (±)‐6,6‐[2H6]dimethyl‐11‐nor‐Δ9‐tetrahydrocannabivarin‐9‐carboxylic acid

Starting from divarinol ( 4 ) using previously published procedures, (±)‐6,6‐[²H₆]Dimethyl‐11‐nor‐Δ⁹THCV‐9‐carboxylic acid ( 3 ) was synthesized for use as an internal standard in GC/MS analysis of 11‐nor‐Δ⁹THCV‐9‐carboxylic acid ( 2 ). The detection of 2 distinguishes the use of marijuana from the ingestion of Marinol^®. Copyright © 2002 John Wiley & Sons, Ltd.     

Beta2‐adrenergic ligand racemic formoterol exhibits enantioselective disposition in blood and skeletal muscle of humans,and elicits myocellular PKA signaling at therapeutic inhaled doses

While studies have demonstrated substantial differences in beta₂‐adrenergic agonist enantiomer pharmacology, enantioselective disposition of long‐acting beta₂‐adrenergic ligand racemic (rac)‐formoterol in blood is inadequately explored after inhaled therapy given analytical challenges. Furthermore, information on enantioselective disposition and partitioning of beta₂‐adrenergic agonist in skeletal muscle is absent despite its promising data on muscle anabolism in humans. Using a sensitive ultra‐high performance liquid chromatography?mass spectrometry (UPLC?MS/MS) assay, we determined disposition of (R,R)‐formoterol and (S,S)‐formoterol in plasma and skeletal muscle samples from 11 non‐asthmatic men who had inhaled rac‐formoterol at therapeutic doses (2 × 27 μg). Mean (SD) concentrations of (R,R)‐ and (S,S)‐formoterol in plasma and in muscle biopsies of the vastus lateralis 1 hour after inhalation of formoterol were 31 (15) and 45 (18) pg × mL^?1 for (R,R)‐formoterol and (S,S)‐formoterol, respectively, in plasma, and 0.56 (0.32) and 0.51 (0.29) pg × mg_{wet wt}^?1, respectively, in muscle. Formoterol exhibited different enantioselective disposition in plasma and muscle (p < 0.0001). In plasma, mean log (R,R):(S,S)‐formoterol ratio was lower than 0 [?0.17(0.07), p < 0.0001], whereas in muscle, mean log (R,R):(S,S)‐formoterol ratio was slightly higher than 0 [0.04(0.07), p < 0.05]. Log (R,R):(S,S)‐formoterol ratio in muscle was related to muscle fiber‐type composition. Furthermore, formoterol induced an approximately two‐fold increase in muscle p‐PKA^Ser/thr phosphorylation (p < 0.01), indicating a substantial beta₂‐adrenergic response. Collectively, these findings suggest that formoterol exhibits modest enantioselective disposition in plasma after inhaled therapy in humans, which appear related to a greater (R,R)‐enantiomer disposition in skeletal muscle that may be dependent on fiber‐type composition.     

The flavonolignan‐silymarin protects enzymatic,hematological, and immune system against γ‐radiation‐induced toxicity

The main focus of this study is evaluation of radioprotective efficacy of silymarin, a flavonolignan, against γ‐radiation‐induced damage to hematological, vital organs (liver and intestine), and immune system. Survival studies revealed that silymarin (administered orally for 3 days) provided maximum protection (67%) at 70 mg/kg body weight (b.wt.) against lethal 9 Gy γ‐irradiation (dose reduction factor = 1.27). The study revealed significant (p < 0.05) changes in levels of catalase (12.57 ± 2.58 to 30.24 ± 4.89 units), glutathione peroxidase (6.23 ± 2.95 to 13.26 ± 1.36 µg of reduced glutathione consumed/min/mg protein), glutathione reductase (0.25 ± 5.6 to 11.65 ± 2.83 pM NADPH consumed/min/mg protein), and superoxide dismutase (11.74 ± 0.2 to 16.09 ± 3.47 SOD U/mg of protein) activity at 30th day. Silymarin pretreated irradiated group exhibited increased proliferation in erythrocyte count (1.76 ± 0.41 × 10⁶ to 9.25 ± 0.24 × 10⁶), hemoglobin (2.15 ± 0.48g/dL to 14.77 ± 0.25g/dL), hematocrit (4.55 ± 0.24% to 37.22 ± 0.21%), and total leucocyte count (1.4 ± 0.15 × 10⁶ to 8.31 ± 0.47 × 10⁶) as compared with radiation control group on 15th day. An increase in CD4:CD8 ratio was witnessed (0.2–1%) at 30th day time interval using flow cytometry. Silymarin also countered radiation‐induced decrease (p < 0.05) in regulatory T‐cells (T_regs) (11.23% in radiation group at 7th day versus 0.1% in pretreated silymarin irradiated group at 15th day). The results of this study indicate that flavonolignan‐silymarin protects enzymatic, hematological, and immune system against γ‐radiation‐induced toxicity and might prove useful in management of nuclear and radiological emergencies. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 641–654, 2016.     

Concluding the trilogy: The interaction of 2,2′‐dihydroxy‐benzophenones and their carbonyl N‐analogues with human glutathione transferase M1‐1 face to face with the P1‐1 and A1‐1 isoenzymes involved in MDR

A series of 2,2′‐dihydroxybenzophenones and their carbonyl N‐analogues were studied as potential inhibitors against human glutathione transferase M1‐1 (hGSTM1‐1) purified from recombinant E. coli. Their screening revealed an inhibition against hGSTM1‐1 within a range of 0‐42% (25 μM). The IC₅₀ values for the two stronger ones, 16 and 13 , were 53.5 ± 5.6 μΜ and 28.5 ± 2.5 μΜ, respectively. The results were compared with earlier ones for isoenzymes hGSTP1‐1 and hGSTA1‐1 involved in MDR. All but one bind more strongly to A1‐1, than M1‐1 and P1‐1, the latter being a poor binder. An order of potency A1‐1 > > M1‐1 >  P1‐1 meritted 13 , 14 and 16 as the most potent inhibitors with hGSTM1‐1. Enzyme kinetics with hGSTM1‐1 (K_m(CDNB) 213 ± 10 μΜ and K_m(GSH) 303 ± 11 μΜ) revealed a competitive modality for 16 (K_i(16) = 22.3 ± 1.1 μΜ) and a mixed one for 13 versus CDNB (K_i(13) = 33.3 ± 1.6 μM for the free enzyme and K_i(13)′ = 17.7 ± 1.7 μM for the enzyme‐CDNB complex). 5‐ or 5′‐Bromo‐ or phenyl‐substituted (but not in combination) inhibitors, having a H‐bonded oxime weakly acidic group of a small volume, are optimal candidates for binding hGSTM1‐1. The outcome of the isoenzyme trilogy identified good binder leads for the investigated GSTs involved in MDR.     

Influence of mefenamic acid on the intestinal absorption and metabolism of three bioactive flavones in Radix Scutellariae and potential pharmacological impact

Context: Mefenamic acid (MEF) and the dried root of Scutellaria baicalensis Georgi (Radix Scutellariae, RS) share a high possibility of combined medication to treat inflammation.

Objective: The present study investigates the impact of MEF on absorption/disposition of three major components in RS (baicalein, B; wogonin, W; oroxylin A, OA) and further pharmacological changes.

Materials and methods: The apparent permeability (P_app) and percentage of metabolism of B, W and OA at 10?μΜ were measured at the absence/presence of MEF (100?μΜ) in the Caco-2 cell monolayer model. A modified whole blood assay was employed to quantify prostaglandin E₂ (PGE₂) 4, 6 and 8?h post-oral administration with water suspension of MEF at 40?mg/kg and RS at 200?mg/kg.

Results: In the presence of MEF, P_app of B, W and OA were increased from 1.69?±?0.89?×?10^?6, 1.57?±?0.10?×?10^?6 and 3.09?±?0.70?×?10^?6?cm/sec to 5.24?±?0.27?×?10^?6, 6.08?±?0.19?×?10^?6 and 4.13?±?0.38?×?10^?6, whereas their percentage of metabolism was decreased from 72.75?±?2.44%, 73.27?±?3.25% and 89.84?±?2.99% to 21.11?±?0.69%, 17.90?±?5.55% and 45.44?±?3.38%. PGE₂ level was much lower in the co-administration group (49.04?±?2.03?pg/ml) than in the MEF group (73.13?±?3.03?pg/ml) or RS group (494.37?±?11.75?pg/ml) 4?h post MEF dosing, suggesting a synergic effect.

Discussion and conclusion: Co-administration of MEF and RS could induce potential alterations in their pharmacokinetic profiles and anti-inflammatory effects.     

Potential excitatory role of nitric oxide on 2‐deoxy‐d‐glucose‐induced gastric motility in rats

Previous studies have shown that 2‐deoxy‐d ‐glucose (2‐DG) increases gastric motility via the vagus nerve, but the underlying mechanism remains elusive. Since nitric oxide (NO) is involved in gastric motility, a possible interplay between 2‐DG and NO can be suggested. In the present study, Wistar rats (250‐350 g) of both sexes were intravenously injected with 2‐DG (200 mg/kg), and the effects of the intravenous injection of the nitric oxide synthase (NOS) inhibitors; nitro‐l ‐arginine methyl ester (l ‐NAME, 10 mg/kg) and N^ω‐nitro‐l ‐arginine (l ‐NNA, 10 mg/kg) were investigated. Animals were anaesthetized and cannulated for intravenous drug injections while the left vagal nerve was electrically stimulated (0.1‐10 Hz, 0.5 ms duration, 12 V, for 60 seconds), and intragastric pressure and gastric motility changes were monitored using a latex gastric balloon. 2‐DG increased the mean intragastric pressure (baseline, 5.0±0.4 cmH₂O; after 2‐DG, 14.4±1.5 cmH₂O; P=.0156) and significantly increased the gastric motility index, while NOS inhibitors significantly attenuated both parameters. However, pretreatment with NOS inhibitors significantly augmented the gastric responses to peripheral electrical vagal stimulation. These results suggest that NO plays an excitatory role in gastric responsiveness to 2‐DG and that this function may be effected in the central nervous system.     

Biopharmaceutics classification and intestinal absorption of chikusetsusaponin IVa

The objective of this study was to investigate the absorption behavior of chikusetsusaponin IVa (CHS‐IVa) in the rat intestine using single‐pass intestinal perfusion (SPIP) and to classify CHS‐IVa into the biopharmaceutics classification system (BCS). The equilibrium solubility of CHS‐IVa was determined by the shaker method. The absorption mechanism of CHS‐IVa in the intestine was studied by comparing the P_eff of different concentrations of CHS‐IVa. The intestinal site dependence of CHS‐IVa absorption was studied by comparing the P_eff of the same concentration of CHS‐IVa in different intestinal segments. The relationship between CHS‐IVa and intestinal efflux protein was studied by perfusion with an efflux protein inhibitor. The permeability of CHS‐IVa was investigated by comparing the P_eff of CHS‐IVa and the reported value. The solubility of CHS‐IVa over the pH range 1.0–7.5 was 14.4 ± 0.29 to 16.9 ± 0.34 mg/ml. The P_eff of CHS‐IVa in the duodenum was 1.76 × 10^?3 to 2.00 × 10^?3 cm/min. The P_eff of CHS‐IVa in the jejunum was 1.26 × 10^?3 to 1.39 × 10^?3 cm/min. The P_eff of CHS‐IVa in the ileum was 1.25 × 10^?3 to 1.31 × 10^?3 cm/min. The P_eff of CHS‐IVa in the colon was 1.02 × 10^?3 to 1.08 × 10^?3 cm/min. There was no statistical difference of the P_eff in the four segments at different CHS‐IVa concentrations. The P_eff of CHS‐IVa (0.07, 0.7 and 7.0 mg/ml) were all notably smaller than the reported P_eff (3.00 × 10^?3 cm/min) in the jejunum. The P_eff of CHS‐IVa was not influenced by verapamil (P‐gp inhibitor), indomethacin (MRP inhibitor) and pantoprazole (BCRP inhibitor). CHS‐IVa was classified as high solubility, low permeability and BCS III. The main absorptive tracts were the upper intestinal tracts and the rank order of intestinal permeability was duodenum > jejunum ≈ ileum > colon. The transport mechanism of CHS‐IVa in all intestinal segments might be primarily passive transport. CHS‐IVa was not a substrate of P‐gp, MRP and BCRP.     

Effects of JTV‐519 on stretch‐induced manifestations of mechanoelectric feedback

JTV‐519 is a 1,4‐benzothiazepine derivative with multichannel effects that inhibits Ca²⁺ release from the sarcoplasmic reticulum and stabilizes the closed state of the ryanodine receptor, preventing myocardial damage and the induction of arrhythmias during Ca²⁺ overload. Mechanical stretch increases cellular Na⁺ inflow, activates the reverse mode of the Na⁺/Ca²⁺ exchanger, and modifies Ca²⁺ handling and myocardial electrophysiology, favoring arrhythmogenesis. This study aims to determine whether JTV‐519 modifies the stretch‐induced manifestations of mechanoelectric feedback. The ventricular fibrillation (VF) modifications induced by acute stretch were studied in Langendorff‐perfused rabbit hearts using epicardial multiple electrodes under control conditions (n=9) or during JTV‐519 perfusion: 0.1 μmol/L (n=9) and 1 μmol/L (n=9). Spectral and mapping techniques were used to establish the baseline, stretch and post‐stretch VF characteristics. JTV‐519 slowed baseline VF and decreased activation complexity. These effects were dose‐dependent (baseline VF dominant frequency: control=13.9±2.2 Hz; JTV 0.1 μmol/L=11.1±1.1 Hz, P<.01; JTV 1 μmol/L=6.6±1.1 Hz, P<.0001). The stretch‐induced acceleration of VF (control=38.8%) was significantly reduced by JTV‐519 0.1 μmol/L (19.8%) and abolished by JTV 1 μmol/L (−1.5%). During stretch, the VF activation complexity index was reduced in both JTV‐519 series (control=1.60±0.15; JTV 0.1 μmol/L=1.13±0.3, P<.0001; JTV 1 μmol/L=0.57±0.21, P<.0001), and was independently related to VF dominant frequency (R=.82; P<.0001). The fifth percentile of the VF activation intervals, conduction velocity and wavelength entered the multiple linear regression model using dominant frequency as the dependent variable (R=−.84; P<.0001). In conclusion, JTV‐519 slowed and simplified the baseline VF activation patterns and abolished the stretch‐induced manifestations of mechanoelectric feedback.     

Rapid synthesis of maleimide functionalized fluorine‐18 labeled prosthetic group using “radio‐fluorination on the Sep‐Pak” method

Following our recently published fluorine‐18 labeling method, “Radio‐fluorination on the Sep‐Pak”, we have successfully synthesized 6‐[¹⁸F]fluoronicotinaldehyde by passing a solution (1:4 acetonitrile: t‐butanol) of its quaternary ammonium salt precursor, 6‐(N,N,N‐trimethylamino)nicotinaldehyde trifluoromethanesulfonate ( 2 ), through a fluorine‐18 containing anion exchange cartridge (PS‐HCO₃). Over 80% radiochemical conversion was observed using 10 mg of precursor within 1 minute. The [¹⁸F]fluoronicotinaldehyde ([¹⁸F] 5 ) was then conjugated with 1‐(6‐(aminooxy)hexyl)‐1H‐pyrrole‐2,5‐dione to prepare the fluorine‐18 labeled maleimide functionalized prosthetic group, 6‐[¹⁸F]fluoronicotinaldehyde O‐(6‐(2,5‐dioxo‐2,5‐dihydro‐1H‐pyrrol‐1‐yl)hexyl) oxime, 6‐[¹⁸F]FPyMHO ([¹⁸F] 6 ). The current Sep‐Pak method not only improves the overall radiochemical yield (50 ± 9%, decay‐corrected, n = 9) but also significantly reduces the synthesis time (from 60‐90 minutes to 30 minutes) when compared with literature methods for the synthesis of similar prosthetic groups.     

Synthesis and evaluation of an 18F‐labeled trifluoroborate derivative of 2‐nitroimidazole for imaging tumor hypoxia with positron emission tomography

2‐Nitroimidazole‐based hypoxia imaging tracers such as ¹⁸F‐FMISO are normally imaged at late time points (several hours post‐injection) due to their slow clearance from background tissues. Here, we investigated if a hydrophilic zwitterion‐based ammoniomethyl‐trifluoroborate derivative of 2‐nitroimidazole, ¹⁸F‐AmBF₃‐Bu‐2NI, could have the potential to image tumor hypoxia at earlier time points. AmBF₃‐Bu‐2NI was prepared in 4 steps. ¹⁸F labeling was conducted via ¹⁸F‐¹⁹F isotope exchange reaction, and ¹⁸F‐AmBF₃‐Bu‐2NI was obtained in 14.8 ± 0.4% (n = 3) decay‐corrected radiochemical yield with 24.5 ± 5.2 GBq/μmol specific activity and >99% radiochemical purity. Imaging and biodistribution studies in HT‐29 tumor‐bearing mice showed that ¹⁸F‐AmBF₃‐Bu‐2NI cleared quickly from blood and was excreted via the hepatobiliary and renal pathways. However, the tumor was not visualized in PET images until 3 hours post‐injection due to low tumor uptake (0.54 ± 0.13 and 0.19 ± 0.04%ID/g at 1 and 3 hours post‐injection, respectively). The low tumor uptake is likely due to the highly hydrophilic motif of ammoniomethyl‐trifluoroborate that prevents free diffusion of ¹⁸F‐AmBF₃‐Bu‐2NI across the cell membrane. Our results suggest that highly hydrophilic ¹⁸F‐labeled ammoniomethyl‐trifluoroborate derivatives might not be suitable for imaging intracellular targets including nitroreductase, a common tumor hypoxia imaging target.     

Effects of selective serotonin reuptake inhibitors on motility of isolated fallopian tube

Selective serotonin reuptake inhibitors (SSRIs) affect the smooth muscle cells acting on voltage‐dependent channels for Na⁺, K⁺ and Ca²⁺, but their action is tissue and species specific. The aim of our study was to investigate effects of selective serotonin reuptake inhibitors on motility of the isolated fallopian tubes. Isolated preparations of isthmus and ampoule were taken from fallopian tubes of 20 women during hysterectomy due to uterine fibroids and then tested for reactivity on increasing concentrations of selective serotonin reuptake inhibitors. Escitalopram (from 0.9 × 10^?9 M/L to 1.4 × 10^?6 M/L) produced concentration‐dependent increase of spontaneous contractions of the isolated ampulla (EC50 = 1.20 ± 1.06 × 10^?8 M/L, r = 0.580, P < 0.05) (F = 2.980, df₁ = 6, df₂ = 28, P < 0.05). Paroxetine (from 1.2 × 10^?9 M/L to 5.1 × 10^?5 M/L) produced concentration‐dependent increase of spontaneous contractions of the isolated isthmus (EC50 = 7.01 ± 3.50 × 10^?8 M/L, r = 0.500, P < 0.05) (F = 2.350, df₁ = 9, df₂ = 40, P < 0.05). The SSRIs differ among themselves in regard to their potential to affect motility of the fallopian tubes. Escitalopram and paroxetine have clear stimulating effect which may interfere with functioning of the fallopian tubes, and potentially impair fertility if taken by women in reproductive period of life. The other SSRIs tested in the study did not produce significant effect throughout the concentration range used in the experiments.     

Technetium‐99m radiolabeling and biological study of epirubicin for in vivo imaging of multi‐drug‐resistant Staphylococcus aureus infections via single photon emission computed tomography

The development of functional imaging is a promising strategy for diagnosis and treatment of infectious and cancerous diseases. In this study, epirubicin was developed as a [^99mTc]‐labeled radiopharmaceutical for the imaging of multi‐drug‐resistant Staphylococcus aureus infections. The labeling was carried out using sodium pertechnetate (Na^99mTcO₄; ~370 MBq). The other parameters such as amount of ligand, reducing agent (SnCl₂.2H₂O), and pH were optimized. The highest labeling yield ≥96.98% was achieved when 0.3 mg epirubicin, 13 μg SnCl₂.2H₂O, and ~370 MBq Na^99mTcO₄ were incubated at pH 7 for 15 min in the presence of ascorbic acid at room temperature. Radiochemical purity, stability, charge, and glomerular filtration rate were studied to evaluate the biological compatibility for in vivo administration. Biodistribution investigations showed radiotracer uptake (13.89 ± 1.56% ID/gm organ) by liver and 7.79 ± 0.38% ID/gm organ by kidneys at 30 min post‐injection which promisingly wash out at 24 hr post‐injection. Scintigraphy study showed selective uptake in S. aureus‐infected tissues in contrast to turpentine oil‐induced inflamed tissues. Target‐to‐non‐target ratio (6.7 ± 0.05) was calculated at 1 hr post‐injection using SPECT gamma camera. The results of this study reveal that the [^99mTc]‐epirubicin can be a choice of imaging and monitoring the treatment process of multi‐drug resistant S. aureus bacterial infections.     

A report of the automated radiosynthesis of the tau positron emission tomography radiopharmaceutical, [18F]‐THK‐5351

The radiotracer, [¹⁸F]‐THK‐5351, is a highly selective and high‐binding affinity PET imaging agent for aggregates of hyper‐phosphorylated tau protein. Our report is a simplified 1‐pot, 2‐step radiosynthesis of [¹⁸F]‐THK‐5351. This report is broadly applicable for routine clinical production and multi‐center trials on account of favorable half‐life of flourine‐18 and the use of a commercially available radiosynthesis module, the GE TRACERlab™ FX_FN. First, the O‐THP protected tosyl precursor underwent nucleophilic fluorinating reaction with potassium cryptand fluoride ([¹⁸F] fluoride (K[¹⁸F]/K₂₂₂)) in Dimethyl sulfoxide at 110°C for 10 minutes followed by O‐THP removal by using diluted hydrochloric acid (HCl) at same temperature. [¹⁸F]‐THK‐5351 was purified via semi‐preparative high‐performance liquid chromatography and formulated by using 10% EtOH, United States Pharmacopeia (USP) in 0.9% sodium chloride for injection, USP and an uncorrected radiochemical yield of 21 ± 3.5%, with a specific activity of 153.11 ± 25.9 GBq/μmol (4138 ± 700 mCi/μmol) at the end of synthesis (63 minutes; n  = 3).     

Apoptotic and antiproliferative properties of 3β‐hydroxy‐Δ5‐steroidal congeners from a partially purified column fraction of Dendronephthya gigantea against HL‐60 and MCF‐7 cancer cells

Organisms belonging to the genus Dendronephthya are among a group of marine invertebrates that produce a variety of terpenoids with biofunctional properties. Many of these terpenoids have been proven effective as anticancer drugs. Here, we report the antiproliferative effect of 3β‐hydroxy‐Δ5‐steroidal congeners against the proliferation of HL‐60 human leukemia cells and MCF‐7 human breast cancer cells. The sterol‐rich fraction (DGEHF2‐1) inhibited the growth of HL‐60 and MCF‐7 cells with IC₅₀ values of 13.59 ± 1.40 and 29.41 ± 0.87 μg ml^–1 respectively. Treatment with DGEHF2‐1 caused a dose‐dependent increase in apoptotic body formation, DNA damage and the sub‐G₁ apoptotic cell population. Moreover, DGEHF2‐1 downregulated the expression of Bcl‐xL while upregulating Bax, caspase‐9, and PARP cleavage in both HL‐60 and MCF‐7 cells. The steroid fraction was found to act via the mitochondria‐mediated apoptosis pathway. Identification of the sterols was performed via gas chromatography–tandem mass spectrometry analysis. Studying the mechanism of the anticancer effect caused by these sterol derivatives could lead to the identification of other natural products with anticancer properties.     

Contribution of a significant first‐pass effect of dimethyl‐4,4′‐dimethoxy‐5,6,5′,6′‐dimethylene dioxybiphenyl‐2,2′‐dicarboxylate in the liver to its poor bioavailability in rats

Objectives The objective of this study was to investigate the mechanism responsible for the poor oral bioavailability of dimethyl-4′,4′-dimethoxy-5,6,5′,6′-dimethylene dioxy-biphenyl-2,2′-dicarboxylate (DDB), a hepatoprotective agent, in rats. Methods DDB was intravenously administered to rats at doses of 0.2-1 mg/kg. To determine the hepatic first-pass effect in rats, DDB (1 mg/kg) was administered via the pyloric vein and the femoral vein. Direct measurement of intestinal permeability was attempted using Caco-2 cell monolayers and rat intestinal epithelium. Key findings A moment analysis indicated that the volume of distribution and clearance remained unchanged with the magnitude of the dose, indicating that DDB exhibited linear pharmacokinetics. When the area under the curve for DDB after administration to the pyloric vein was compared with that after femoral vein administration, the ratio (F_H) was found to be 0.294, indicating a significant first-pass effect for DDB. The permeability of DDB was high in the rat intestine (1.78 ± 0.229 × 10⁻⁵ cm/s) and in Caco-2 cell monolayers (6.8 ± 0.70 × 10⁻⁵ cm/s), suggesting that DDB, in soluble form, was readily permeable across the intestinal epithelium. Conclusions These observations indicated that despite the fact that DDB was readily permeable to the intestinal epithelium, a significant first-pass metabolism was associated with its pharmacokinetics in rats.     

Depotentiation of intact rat cardiac muscle unmasks an Epac‐dependent increase in myofilament Ca2+ sensitivity

Recently, a family of guanine nucleotide exchange factors have been identified in many cell types as important effectors of cyclic adenosine 3′,5′‐monophospahte (cAMP) signalling that is independent of protein kinase A (PKA). In the heart, investigation of exchange protein directly activated by cAMP (Epac) has yielded conflicting results. Since cAMP is an important regulator of cardiac contractility, this study aimed to examine whether Epac activation modulates excitation–contraction coupling in ventricular preparations from rat hearts. The study used 8‐(4‐chlorophenylthio)‐2′‐O‐methyladenosine‐3′, 5′‐cyclic monophosphate (cpTOME), an analogue of cAMP that activates Epac, but not PKA. In isolated myocytes, cpTOME increased Ca²⁺ spark frequency from about 7 to 32/100 μm³/s (n = 10), P = 0.05 with a reduction in the peak amplitude of the sparks. Simultaneous measurements of intracellular Ca²⁺ and isometric force in multicellular trabeculae (n = 7, 1.5 mmol/L [Ca²⁺]_o) revealed no effect of Epac activation on either the amplitude of Ca²⁺ transients (Control 0.7 ± 0.1 vs cpTOME 0.7 ± 0.1; 340/380 fura‐2 ratio, P = 0.35) or on peak stress (Control 24 ± 5 mN/mm² vs cpTOME 23 ± 5 mN/mm², P = 0.20). However, an effect of Epac in trabeculae was unmasked by lowering extracellular [Ca²⁺]_o. In these depotentiated trabeculae, activation of the Epac pathway increased myofilament Ca²⁺ sensitivity, an effect that was blocked by addition of KN‐93, a Ca²⁺/calmodulin‐dependent protein kinase II (CaMK‐II) inhibitor. This study suggests that Epac activation may be a useful therapeutic target to increase the strength of contraction during low inotropic states.     

Characterization of hallucinogenic phenethylamines using high‐resolution mass spectrometry for non‐targeted screening purposes

Hallucinogenic phenethylamines such as 2,5‐dimethoxyphenethylamines (2C–X) and their N ‐(2‐methoxybenzyl) derivatives (25X–NBOMe) have seen an increase in novel analogues in recent years. These rapidly changing analogues make it difficult for laboratories to rely on traditional targeted screening methods to detect unknown new psychoactive substances (NPS). In this study, twelve 2C–X, six 2,5‐dimethoxyamphetamines (DOX), and fourteen 25X–NBOMe derivatives, including two deuterated derivatives (2C–B‐d ₆ and 25I–NBOMe‐d ₉), were analyzed using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry (UPLC‐QTOF‐MS). Collision‐induced dissociation (CID) experiments were performed using collision energies set at 10, 20, and 40 eV. For 2C–X and DOX derivatives, common losses were observed including neutral and radical losses such as NH₃ (17.0265 Da), •CH₆N (32.0500 Da), C₂H₇N (45.0578 Da) and C₂H₉N (47.0735 Da). 2C–X derivatives displayed common product ions at m/z 164.0837 ([C₁₀H₁₂O₂]^+•), 149.0603 ([C₉H₉O₂]⁺), and 134.0732 ([C₉H₁₀O]^+•) while DOX derivatives had common product ions at m/z 178.0994 ([C₁₁H₁₄O₂]^+•), 163.0754 ([C₁₀H₁₁O₂]⁺), 147.0804 ([C₁₀H₁₁O]⁺), and 135.0810 ([C₉H₁₁O]⁺). 25X–NBOMe had characteristic product ions at m/z 121.0654 ([C₈H₉O]⁺) and 91.0548 ([C₇H₇]⁺) with minor common losses corresponding to 2‐methylanisole (C₈H₁₀O, 122.0732 Da), 2‐methoxybenzylamine (C₈H₁₁NO, 137.0847 Da), and •C₉H₁₄NO (152.1074 Da). Novel analogues of the selected classes can be detected by applying neutral loss filters (NLFs) and extracting the common product ions. Copyright © 2017 John Wiley & Sons, Ltd.     

Design,synthesis and in vitro antiplasmodial activity of some bisquinolines against chloroquine‐resistant strain

A series of novel bisquinoline compounds comprising N¹‐(7‐chloroquinolin‐4‐yl) ethane‐1,2‐diamine and 7‐chloro‐N‐(2‐(piperazin‐1‐yl)ethyl)quinolin‐4‐amine connected with 7‐chloro‐4‐aminoquinoline containing various amino acids is described. We have bio‐evaluated the compounds against both chloroquine‐sensitive (3D7) and chloroquine‐resistant (K1) strains of Plasmodium falciparum in vitro. Among the series, compounds 4 and 7 exhibited 1.8‐ and 10.6‐fold superior activity as compared to chloroquine (CQ; IC₅₀ = 0.255 ± 0.049 μm ) against the K1 strain with IC₅₀ values 0.137 ± 0.014 and 0.026 ± 0.007 μm , respectively. Furthermore, compound 7 also displayed promising activity against the 3D7 strain (IC₅₀ = 0.024 ± 0.003 μm ) of P. falciparum when compared to CQ. All the compounds in the series displayed resistance factor between 0.57 and 4.71 as against 51 for CQ. These results suggest that bisquinolines can be explored for further development as new antimalarial agents active against chloroquine‐resistant P. falciparum.     

Synthesis of (R)‐ and (S)‐[O‐methyl‐11C]N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐(4‐methoxy‐phenyl)‐urea as candidate high affinity β1‐adrenoceptor PET radioligands

Molecular imaging and quantification of myocardial β₁‐adrenoceptor (AR) rather than total β‐AR density is of great clinical interest since cardiac biopsy studies suggest that myocardial β₁‐AR density is reduced in patients with chronic heart failure whereas cardiac β₂‐AR density may vary. Positron emission tomography (PET), with appropriate radioligands, offers the possibility to assess β‐AR density non‐invasively in humans. However, no PET radioligand for the selective imaging of cardiac β₁‐ARs is clinically available. Here some derivatives of the well characterized β₁‐AR selective antagonist, ICI 89,406, namely the enantiomers of N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐(4‐hydroxy‐phenyl)‐urea ( 5a and 5b ) were synthesized and evaluated in vitro. The (R)‐isomer 5a was more β₁‐selective but has lower affinity than its (S)‐enantiomer 5b (β₁‐AR selectivity: 6100 vs 1240; β₁‐affinity: K₁ = 0.288 nM vs K₁ = 0.067 nM). Etherification of the analogous desmethyl precursors, 5e and 5f , respectively, with [¹¹C]iodomethane gave ¹¹C‐labelled versions of 5a and 5b , namely 5g and 5h , in 44 ± 5% radiochemical yield (decay‐corrected) and 97.4 ± 1.3% radiochemical purity with specific radioactivities of 26.4 ± 9.4 GBq/µmol within 41.2 ± 3.4 min from the end of bombardment (n = 14). 5g and 5h are now being evaluated as candidate radioligands for myocardial β₁‐ARs. Copyright © 2005 John Wiley & Sons, Ltd.