Actions of redox-active compound resveratrol under hydrogen peroxide insult in C6 astroglial cells

The mechanisms by which resveratrol (3,5,4′-trihydroxy-stilbene) imparts neural effects is not well understood. We previously demonstrated that, depending upon the concentration of resveratrol and the cell type, this compound exerts anti-or pro-oxidant effects. In the present study, we investigated the effects of resveratrol on H₂O₂-mediated genotoxicity in C6 astroglial cells (I – 1 mM H₂O₂/30 min or II – 0.1 mM H₂O₂/6 h), evaluated by micronucleus assay, lipid peroxidation (TBARS) and membrane integrity. H₂O₂ increased micronuclei to 1.5 (I) and 1.7-fold (II), compared to control cells. This DNA damage was prevented (I) or partially prevented (II) by resveratrol. Oxidative insult also increased TBARS, 52% in I and 38% in II, P < 0.05. These effects were prevented by resveratrol in I and increased in II (70% of increase). Present data contribute to the understanding of resveratrol effects under oxidative stress damage.     

In vitro tests of resveratrol radiomodifying effect on rhabdomyosarcoma cells by comet assay

Cancer is a global public health problem. Resveratrol is a defensive polyphenol that is synthesized by a wide variety of plants in response to exposure to ultraviolet radiation or also due to mechanical stress caused by the action of pathogens and chemical and physical agents. Grape vines have a high capacity to produce resveratrol, so grape juice and wine, mainly red wine, are considered good sources of resveratrol. The protective effects of resveratrol include promotion of antiinflammatory response, antitumor activity and prevention of degenerative diseases, reduced incidence of cardiovascular diseases and inhibition of platelet aggregation, among others. Therefore, resveratrol is considered to be a cell protector. However, at high concentrations, resveratrol promotes contrary effects by sensitizing cells. The aim of this study was to investigate in vitro the radiomodifying effect of resveratrol in culture of human rhabdomyosarcoma cells (RD) by applying the comet assay to evaluate the cell damage and repair capacity. The LD₅₀ (lethal dose) obtained was 499.95 ± 9.83 Gy (Mean ± SD) and the CI₅₀ (cytotoxicity index) was 150 μM in the RD cells. Based on these data, it was defined the gamma radiation doses (50 and 100 Gy) and resveratrol concentrations (15, 30 and 60 μM) to be used in this study. The results indicated that resveratrol acts as a cell protector at a concentration of 15 μM and has a cytotoxic effect at 60 μM. However, with the interaction of the gamma radiation, the concentration of 60 μM did not produce a statistically significant radiosensitizing effect.     

Lasting effect of preceding culture conditions on the susceptibility of C6 cells to peroxide-induced oxidative stress

The aim of the present study was to investigate the influence of the maintenance culture conditions on the competence of C6 rat glioma cells to cope with peroxide-induced oxidative stress. C6 cells were maintained either in Ham’s nutrient mixture F-10 supplemented with 15% horse serum and 2.5% foetal bovine serum (FBS) or in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 5% FBS. The differently cultured cells were exposed under identical conditions to hydrogen peroxide (H₂O₂) and cumene hydroperoxide (CHP) in serum-free DMEM. The cells maintained in high serum Ham’s F-10 medium (1) were less sensitive towards the cytotoxic action of both peroxides (EC₅₀-values: H₂O₂: 193 ± 23 μM; CHP: 94 ± 16 μM) than the cells maintained in low serum DMEM (EC₅₀-values: H₂O₂: 51 ± 10 μM; CHP: 27 ± 11 μM), (2) eliminated the peroxides (initial concentration: 100 μM) with higher rates (H₂O₂: 56 ± 5.5 vs. 32 ± 2.7, CHP: 32 ± 6 vs. 3.4 ± 0.6 nmol/min mg protein), (3) contained more glutathione (30 ± 2.5 vs. 14 ± 1.1 nmol/mg protein) and (4) owned a higher glutathione peroxidase activity (28 ± 3.4 vs. 9.5 ± 0.8 mU/mg protein). Glutathione reductase and catalase activities were not affected. These results demonstrate that the preceding culture conditions have a lasting effect on the susceptibility of cultured cells to oxidative stressors like peroxides. As cause for these differences a dissimilar supply of the cells with serum born antioxidants like selenium and α-tocopherol is discussed.     

Solid self-emulsifying nitrendipine pellets: Preparation and in vitro/in vivo evaluation

Objective of this study is to develop and evaluate the new solid self-emulsifying (SE) pellets of poorly soluble nitrendipine (NTD). These pellets were prepared via extrusion/spheronization technique, using liquid SEDDS (NTD, Miglyol^® 812, Cremophor^® RH 40, Tween 80, and Transcutol^® P), adsorbents (silicon dioxide and crospovidone), microcrystalline cellulose and lactose. The resulting SE pellets with 30% liquid SEDDS exhibited uniform size (800–1000 μm) and round shape, droplet size distribution following self-emulsification was nearly same to the liquid SEDDS (72 ± 16 nm and 64 ± 12 nm). The in vitro release was similar for the two SE formulations (over 80% within 30 min), both significantly higher than the conventional tablets (only 35% within 30 min). The oral bioavailability was evaluated for the SE pellets, liquid SEDDS and conventional tablets in fasted beagle dogs. AUC of NTD from the SE pellets showed 1.6-fold greater than the conventional tablets and no significant difference compared with the liquid SEDDS. In conclusion, our studies illustrated that extrusion/spheronization technique could be a useful large-scale producing method to prepare the solid SE pellets from liquid SEDDS, which can improve oral absorption of NTD, nearly equivalent to the liquid SEDDS, but better in the formulation stability, drugs leakage and precipitation, etc.     

Genotoxicity and antileishmanial activity evaluation of Physalis angulata concentrated ethanolic extract

Antileishmanial in vitro tests, as well as Ames and micronucleus assays were performed with a concentrated ethanolic extract of Physalis angulata (EEPA)ResultsEEPA did not present mutagenic effect in Salmonella typhimurium strains at concentration reaching 3000 μg/plate and did not induce mutagenic effects after two oral administrations with a 24 h interval at a dose level of 2000 mg/kg. EEPA presented antileishmanial activity and presented an IC₅₀ value of 5.35 ± 2.50 μg/mL and 4.50 ± 1.17 μg/mL against Leishmania amazonensis and Leishmania braziliensis promastigotes, respectively. In the cytotoxicity test against macrophages, the EEPA had a LC₅₀ of 6.14 ± 0.59 μg/mL. Importantly, the IC₅₀ against L. amazonensis intracellular amastigotes was 1.23 ± 0.11 μg/mL.ConclusionEEPA extract is non-mutagenic and presented a promising pharmacological effect against Leishmania parasites.     

Neuroprotective effects of neolignans isolated from Magnoliae Cortex against glutamate-induced apoptotic stimuli in HT22 cells

In the course of screening for neuroprotective natural products, Magnoliae Cortex showed potent inhibition of hippocampal neuronal HT22 cell death. Obovatol, honokiol, and magnolol were isolated from the ethanolic extract of Magnoliae Cortex. Isolated compounds obovatol, honokiol, and magnolol were protective against 5 mM glutamate-induced cell death. When cells were stressed using glutamate, cell viability decreased to 16.98 ± 4.58% over the control (100.00 ± 10.15%). In contrast, 10 μM obovatol, 10 μM honokiol, and 50 μM magnolol increased cell viability to 91.80 ± 1.70%, 93.59 ± 1.93%, and 85.36 ± 7.40%, respectively. The neuroprotective effects of obovatol and honokiol were attributable to the inhibition of intracellular reactive oxygen species production, followed by protection of the mitochondrial membrane potential (ΔΨ_m), recovery of Bcl-2 and Bid levels, inhibition of apoptosis-inducing factor expression, and phosphorylation of mitogen-activated protein kinases such as p38 kinases, extracellular signal-regulated kinases, and c-Jun N-terminal kinases. On the contrary, magnolol did not show any significant effect on the ΔΨ_m and apoptotic factors. Among three compounds, obovatol most strongly scavenged 2,2-diphenyl-1-picrylhydrazyl radicals and inhibited the elevation of intracellular reactive oxygen species levels in glutamate-stressed HT22 cells. These data suggest that obovatol and honokiol may have clinical applications for preventing neurodegenerative disorders.     

The effects of Ficus carica on the activity of enzymes related to metabolic syndrome

The present study aimed to investigate the effects of the various parts of Ficus carica L. (figs) on antioxidant, antidiabetic, and antiobesogenic effects in vitro. Fruit, leaves, and stembark of the F. carica plant were sequentially extracted using organic and inorganic solvents and their total polyphenol and flavonoid contents were estimated. The effects of the extracts on antioxidative, antidiabetic (inhibition of α-amylase and α-glucosidase enzymes), and antiobesogenic (antilipase) activities were measured using several experimental models. The fruit ethanolic extract contained a high quantity of polyphenols and flavonoids (104.67 ± 5.51 μg/mL and 81.67 ± 4.00 μg/mL) compared with all other extracts. The activity of the ethanolic extract of F. carica fruit was significantly (p < 0.05) higher than all other extracts and parts of the plant in terms of antioxidative, antidiabetic, and antiobesogenic effects. The IC₅₀ values of the fruit ethanolic extract in terms of antioxidative (134.44 ± 18.43 μg/mL), and inhibition of α-glucosidase (255.57 ± 36.46 μg/mL), α-amylase (315.89 ± 3.83 μg/mL), and pancreatic lipase (230.475 ± 9.65 μg/mL) activity indicate that the activity of fruit ethanolic extract is better than all other extracts of the plant. The gas chromatography–mass spectroscopy analysis of the fruit ethanolic extract showed the presence of a number of bioactive compounds such as butyl butyrate, 5-hydroxymethyl furfural, 1-butoxy-1-isobutoxy butane, malic acid, tetradecanoic acid, phytol acetate, trans phytol, n-hexadecanoic acid, 9Z,12Z-octadecadienoic acid, stearic acid, sitosterol, 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one, and 2,4,5-trimethyl-2,4-dihydro-3H-pyrazol-3-one. The results of this study suggest that the ethanolic extract of the fruit of F. carica may have potential antidiabetic and antiobesogenic agents.     

Levosimendan and its metabolite OR-1896 elicit KATP channel-dependent dilation in resistance arteries in vivo

BackgroundLevosimendan and its long-lived metabolite OR-1896 produce vasodilation in different types of vessels by activating ATP-sensitive (K_ATP) and other potassium channels.MethodsIn the present study we applied intravital videomicroscopy to investigate the in situ effects of levosimendan and OR-1896 on the diameters of real resistance arterioles (rat cremaster muscle arterioles with diameters of ~ 20 μm).ResultsLevosimendan and OR-1896 induced concentration-dependent (1 nM – 100 μM) dilations to similar extents in these arterioles (maximal dilation from 23 ± 2 to 33 ± 2 μm and from 22 ± 1 to 32 ± 1 μm, respectively). The arteriolar dilations induced by the selective K_ATP channel opener pinacidil (1 nM – 10 μM) (maximal dilation from 22 ± 4 μm to 35 ± 3 μm) were diminished in the presence of the selective K_ATP channel blocker – glibenclamide (5 μM) (maximal diameter attained: 22 ± 1 μm). Glibenclamide also counteracted the maximal dilations in response to levosimendan or OR-1896 (to 23 ± 3 μm or 22 ± 5 μm, respectively).ConclusionsIn conclusion, this is the first demonstration that levosimendan and OR-1896 elicit arteriolar dilation in vivo, via activation of K_ATP channels in real resistance vessels in the rat.     

Chemical composition,antiproliferative and antioxidant properties of lipid classes in ordinary and dark muscles from chub mackerel (Scomber japonicus)

This study investigated to compare lipid profiles in ordinary and dark muscles from chub mackerel and to examine antiproliferative and antioxidative properties of lipid classes. The average levels of neutral lipids (NL), glycolipids (GL), and phospholipids (PL) in ordinary muscle were 92.32 ± 0.19%, 5.10 ± 0.48%, and 2.58 ± 0.46%; in dark muscle were 96.88 ± 0.15%, 2.59 ± 0.36%, and 0.54 ± 0.29%, respectively. The fatty acid composition indicated that PL had a higher percentage of PUFA (especially 22:6n?3) with lower percentages of SFA and MUFA compared to NL and GL (p < 0.05). The main ion peaks of GL in ordinary and dark muscles showed that monocharged and bischarged molecular ion were presented at m/z 876.9 and 438.8, respectively. In MTT assay, inhibition of AGS and HT-29 cell proliferation was greatest with the 0.5 and 1.0 mg mL^?1 GL treatments. The GL of ordinary muscle with 0.05 mg mL^?1 concentrations markedly decreased the levels of reactive oxygen species (ROS) induced by H₂O₂ compared to the control (p < 0.05). From our results, GL might have antiproliferative and antioxidant properties based on protective effect against the production of intracellular ROS.     

Impact of iron oxide nanoparticles on brain,heart, lung,liver and kidneys mitochondrial respiratory chain complexes activities and coupling

The present study evaluates the effects of iron oxide nanoparticles (ION) on mitochondrial respiratory chain complexes activities in five organs characterized by different oxidative capacities and strongly involved in body detoxification. Isolated mitochondria were extracted from brain, heart, lung, liver and kidneys in twelve Wistar rats (8 weeks) using differential centrifugations. Maximal oxidative capacities (Vmax), mitochondrial respiratory chain complexes activity using succinate (Vsucc, complexes II, III, and IV activities) or N, N, N′, N′-tetramethyl-p-phenylenediaminedihydrochloride (tmpd)/ascorbate (Vtmpd, complex IV activity) and, mitochondrial coupling (Vmax/Vo) were determined in controls and after exposure to 100, 200, 300 and 500 μg/ml Fe₃O₄. Data showed that baseline maximal oxidative capacities were 26.3 ± 4.7, 48.9 ± 4.6, 11.3 ± 1.3, 27.0 ± 2.5 and 13.4 ± 1.7 μmol O₂/min/g protein in brain, heart, lung, liver, and kidneys mitochondria, respectively. Complexes II, III, and IV activities also significantly differed between the five organs. Interestingly, as compared to baseline values and in all tissues examined, exposure to ION did not alter mitochondrial respiratory chain complexes activities whatever the nanoparticles (NPs) concentration used. Thus, ION did not show any toxicity on mitochondrial coupling and respiratory chain complexes I, II, III, and IV activities in these five major organs.     

Protective effects of dehydrocostus lactone against hydrogen peroxide-induced dysfunction and oxidative stress in osteoblastic MC3T3-E1 cells

Oxidative stress regulates cellular functions in multiple pathological conditions, including bone formation by osteoblasic cells. To elucidate the protective effects of dehydrocostus lactone on the response of osteoblast to oxidative stress, osteoblastic MC3T3-E1 cells were incubated with 0.3 mM hydrogen peroxide (H₂O₂) and/or dehydrocostus lactone (0.1–10 μg/ml), and markers of osteoblast function and oxidative damage were examined. Dehydrocostus lactone (0.1–10 μg/ml) significantly increased osteoblast growth compared with control (P < 0.05). H₂O₂-induced reduction of differentiation markers such as alkaline phosphatase (ALP), collagen content, and calcium deposition was recovered in the presence of dehydrocostus lactone (0.4–2 μg/ml). Treatment with dehydrocostus lactone (10 μg/ml) decreased the production of osteoclast differentiation-inducing factors such as interleukin (IL)-6 and receptor activator of nuclear factor-kB ligand (RANKL) in the presence of H₂O₂. Moreover, dehydrocostus lactone (0.4–2 μg/ml) decreased the formation of protein carbonyl (PCO) and malondialdehyde (MDA) induced by H₂O₂ in osteoblasts. Taken together, these results demonstrate that dehydrocostus lactone can protect osteoblasts against H₂O₂-induced cellular dysfunction. These results also suggest that dehydrocostus lactone may be valuable as a protective agent against oxidative damage in osteoblasts.     

Clinical Pharmacokinetics of Paclitaxel Liposome with a New Route of Administration in Human Based on the Analysis with Ultra Performance Liquid Chromatography

We investigated the clinical pharmacokinetics of paclitaxel liposome with a new route of administration, which was intrapleural infusion, in nine advanced nonsmall-cell lung cancer (NSCLC) patients with malignant pleural effusions after a single administration. Paclitaxel concentrations were measured in pleural fluid and plasma using a simple and rapid ultra performance liquid chromatography (UPLC) method following intra-and inter-day validations. In subjects, AUC_0–96h values in pleural fluid and plasma were 17831 ± 6439 μgh/mL and 778 ± 328 μgh/mL, respectively, and T_max values were initial time and 6.67 h after administration and the corresponding C_max values were 558 ± 44 μg/mL and 12.89 ± 6.86 μg/mL, respectively. The T_{1/2 IP}, CL_IP and Vd_IP values in pleural fluid were 76 ± 48 h, 0.005 ± 0.002 L/hm² and 0.53 ± 0.23 L/m², respectively. The T_1/2,_pla, CL_pla, and Vd_pla values in plasma were 68.34 ± 56.74 h, 0.184 ± 0.080 L/hm², and 17.53 ± 16.57 L/m², respectively. However, some paclitaxel concentrations from several patients in plasma could not be detected at some designed time-points. Our results might offer new opportunities to design and determine individually appropriate therapeutic dosage regimens based on a pharmacokinetic profile.     

Phenolic constituents of Pulicaria undulata (L.) C.A. Mey. sub sp. undulata (Asteraceae): Antioxidant protective effects and chemosystematic significances

One new naturally isoflavone compound, 5,7,2′,3′,4′ penta hydroxyl isoflavone-4′-O-β-glucopyranoside (1) was isolated from the aqueous methanol extract (AME) of Pulicaria undulata subsp. undulata, together with seven known compounds: kaempferol (2), kaempferol 3-O-β-glucoside (3), quercetin (4), quercetin 3-O-β-glucoside (5), quercetin 3-O-β-galactoside (6), quercetin 3,7-di OCH₃ (7), and caffeic acid (8). Their structures were established through chemical (acid hydrolysis) and spectral analysis (UV, NMR, and ESIM). The AME and some isolated compounds were evaluated as protective agents. Free radical scavenging using a microscaled 2,2-diphenyl-1-picrylhydrazyl assay was used to assess the direct antioxidant properties that were evaluated by the ability to protect murine Hepa1c1c7 liver cells against damage induced by the organic peroxide tert-butyl hydroperoxide. The neutral red uptake assay (NRU) was used to record the activity. Results of the 2,2-diphenyl-1-picrylhydrazyl assay recorded differential scavenging properties in ascending order: 5,7,2′,3′,4′ penta hydroxyl isoflavone-4′-O-β-glucopyranoside > quercetin > quercetin 3-O-galactoside > caffeic acid > quercetin 3,7-di-OCH₃ > kaempferol with 50% inhibitory concentrations of 3.9 μM, 7.5 μM, 11.4 μM, 12.2 μM, 78.1 μM, and 252.3 μM, respectively. The antioxidative potential reveals the potency of AME, quercetin, and quercetin 3,7-di-OCH₃. The latter compound showed full protection at 100 μM (33 μg/mL) against the induced toxicant effect where the 50% effective concentration was calculated as 33.6 ± 1.7 μM (11.1 μg/mL). In addition to quercetin, which was extensively shown previously as a cytoprotective agent, AME was less potent; it was capable of protecting 75% at 100 μg/mL with 50% effective concentration of 92.3 ± 4 μg/mL. Moreover, the isolated flavonoids were found to be significantly chemosystematic markers.     

Penetration of doripenem into prostatic tissue following intravenous administration in prostatectomy patients

This study examined the prostatic penetration of doripenem in prostatectomy patients. Doripenem 500 mg was administered by a 0.5-h infusion and venous blood and prostatic tissue samples were obtained up to 5 h afterwards. Drug concentrations in plasma and prostatic tissue were measured chromatographically. The observed maximum concentration (C_max) (mean ± standard deviation; n = 9) was 27.5 ± 5.1 μg/mL in plasma and 5.09 ± 1.94 μg/g in prostate tissue and the prostate/plasma C_max ratio was 0.189 ± 0.078. The area under the drug concentration–time curve (AUC) was 49.7 ± 6.9 μg h/mL in plasma and 3.93 ± 1.89 μg h/g in prostate tissue and the prostate/plasma AUC ratio was 0.081 ± 0.047. Based on a three-compartment pharmacokinetic analysis, average drug exposure times above 0.25 μg/mL (the minimum inhibitory concentration for isolates of common pathogens) in the prostate were 23.2% for 500 mg once daily, 46.2% for 500 mg twice daily and 69.9% for 500 mg three times daily. The 500-mg regimens all achieved the drug exposure time target (bacteriostatic 20% or bactericidal 40%) in the prostate, despite the relatively low penetrability of doripenem.     

Rabbit erythrocytes release ATP and dilate skeletal muscle arterioles in the presence of reduced oxygen tension

In skeletal muscle, oxygen (O₂) delivery to appropriately meet metabolic need requires mechanisms for detection of the magnitude of O₂ demand and the regulation of O₂ delivery. Erythrocytes, when exposed to a decrease in O₂ tension, release both O₂ and the vasodilator adenosine triphosphate (ATP). The aims of this study were to establish that erythrocytes release ATP in response to reduced O₂ tension and determine if erythrocytes are necessary for the dilation of isolated skeletal muscle arterioles exposed to reduced extraluminal O₂ tension. Rabbit erythrocytes exposed to reduced O₂ tension in a tonometer (n = 5, pO₂ = 27 ± 3, p < 0.01) released ATP in response to reduced O₂ tension. ATP release increased in proportion to the decrease in O₂ tension. The contribution of erythrocytes to the response of skeletal muscle arterioles to reduced extraluminal O₂ tension was determined using isolated hamster cheek pouch retractor muscle arterioles perfused with buffer (n = 11, mean diameter 52 ± 3 μm) in the absence and presence of rabbit erythrocytes. Without erythrocytes, arterioles did not dilate when exposed to reduced extraluminal O₂ tension (pO₂ = 32 ± 4 mmHg). In contrast, when rabbit erythrocytes were present in the perfusate (hematocrit 15%), the same decrease in O₂ tension resulted in a 20 ± 4% dilation (p < 0.01). These results provide support for the hypothesis that erythrocytes, via their ability to release O₂ along with ATP in response to exposure to reduced O₂ tension, can participate in the matching of O₂ delivery with metabolic need in skeletal muscle.     

Continuous versus intermittent infusion of cefepime in neurosurgical patients with post-operative intracranial infections

Cefepime is administered as an intermittent infusion (II); however, continuous infusion (CI) may be advantageous because β-lactam antibiotics exhibit time-dependent antibacterial activity. This retrospective, non-randomised, comparative study included 68 neurosurgical patients with post-operative intracranial infections treated with 4 g/day cefepime over 24 h as a CI (n = 34) or 2 g every 12 h as II (n = 34). CI controlled the intracranial infection more rapidly and effectively than II (6.6 ± 1.9 days vs. 7.8 ± 2.6 days; P = 0.036). By considering the minimum inhibitory concentrations (MICs) to be 4 μg/mL and 8 μg/mL, the percentage of time when the cefepime plasma or CSF concentrations were higher than the MIC (%T_>MIC) was calculated for each patient. For plasma cefepime concentrations, the %T_>MIC in the CI group was higher than in the II group (for MICs of 8 μg/mL, 100% vs. 75%, respectively). The mean calculated area under the curve (AUC) in the CI group was similar to the II group (1197.99 ± 72.15 μg h/mL vs. 890.84 ± 140.78 μg h/mL; P = 0.655). For CSF cefepime concentrations, the %T_>MIC in the CI group was higher than in the II group (for MICs of 4 μg/mL and 8 μg/mL, 83.3% and 75% vs. 25% and 0%, respectively). The mean calculated AUC for the CI group was higher than the II group (220.56 ± 13.59 μg h/mL vs. 86.34 ± 5.69 μg h/mL; P = 0.003). Therefore, CI of cefepime significantly enhanced the antibacterial effect and reduced the treatment duration in neurosurgical patients with post-operative intracranial infections.     

Therapeutic efficacy of infused molecular hydrogen in saline on rheumatoid arthritis: A randomized,double-blind,placebo-controlled pilot study

The aim of this study was to demonstrate the safety and efficacy of H₂-saline infusion for treatment of rheumatoid arthritis (RA). We conducted a randomized, double-blind, placebo-controlled investigation of the infusion of 1 ppm H₂-dissolved saline (H₂-saline) in 24 RA patients. Patients were randomized 1:1 to receive 500 ml of either H₂-saline or placebo-saline, which was drop infused intravenously (DIV) daily for 5 days. The disease activity score in 28 joints (DAS28) was measured at baseline, immediately post infusion, and after 4 weeks. Therapeutic effects of H₂-saline on joint inflammation were estimated by measuring serum biomarkers for RA, tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), matrix metalloproteinase-3 (MMP-3), and urinary 8-hydroxydeoxyguanosine (8-OHdG). In the H₂-infused group, average DAS28 decreased from 5.18 ± 1.16 to 4.02 ± 1.25 immediately post infusion and reached 3.74 ± 1.22 after 4 weeks. No significant decrease in DAS28 was observed in the placebo group throughout the study. IL-6 levels in the H₂ group significantly decreased in 4 weeks by 37.3 ± 62.0% compared to baseline, whereas it increased by 33.6 ± 34.4% in the placebo group. TNFα levels did not change remarkably in the H₂ or placebo groups in 4 weeks post-infusion compared to baseline. The relative ratio of 8-OHdG in the H₂ group also significantly decreased by 4.7%. After 4 weeks, MMP3 was significantly reduced by 19.2% ± 24.6% in the H₂ group, and increased by 16.9% ± 50.2% in the placebo group. Drop infusion of H₂ safely and effectively reduced RA disease activity.     

Hydrogen peroxide increases nerve-evoked contractions in mouse tail artery by an endothelium-dependent mechanism

Reactive oxygen species contribute to regulating the excitability of vascular smooth muscle. This study investigated the actions of the relatively stable reactive oxygen species, H₂O₂, on nerve-evoked contractions of mouse distal tail artery. H₂O₂ (10–100 μM) increased nerve-evoked contractions of isometrically mounted segments of tail artery. Endothelium denudation increased nerve-evoked contractions and abolished the facilitatory effect of H₂O₂. Inhibition of nitric oxide synthase with l-nitroarginine methyl ester (0.1 mM) also increased nerve-evoked contractions and reduced the late phase of H₂O₂-induced facilitation. H₂O₂-induced facilitation of nerve-evoked contractions depended, in part, on synthesis of prostanoids and was reduced by the cyclooxygenase inhibitor indomethacin (1 μM) and the thromboxane A₂ receptor antagonist SQ 29548 (1 μM). H₂O₂ increased sensitivity of nerve-evoked contractions to the α₂-adrenoceptor antagonist idazoxan (0.1 μM) but not to the α₁-adrenoceptor antagonist prazosin (10 nM). Idazoxan and the α_2C-adrenoceptor antagonist JP 1302 (0.5–1 μM) reduced H₂O₂-induced facilitation. H₂O₂ induced facilitation of nerve-evoked contractions was abolished by the non-selective cation channel blocker SKF-96365 (10 μM), suggesting it depends on Ca²⁺ influx. In conclusion, H₂O₂-induced increases in nerve-evoked contractions depended on an intact endothelium and were mediated by activating thromboxane A₂ receptors and by increasing the contribution of α₂-adrenoceptors to these responses.     

Characterization and structure-activity relationship of natural flavonoids as hERG K+ channel modulators

ObjectivesFlavonoids are present in varying concentrations in plant foods and have been reported to have numerous pharmacological activities, such as anti-cancer, antioxidant, anti-inflammatory, hepatoprotective, and vasodilator effects. We found that quercetin, fisetin, and some related flavonoid derivatives could inhibit human ether-à-go-go-related gene (hERG) K⁺ channels.Key findingsIn this study, we tested the effects of a series of flavonoids on the hERG K⁺ channel expressed in HEK293 cells. For the first time, we demonstrate that quercetin and fisetin (Fise) are potent hERG current blockers. The 50% inhibiting concentration (IC₅₀) and maximum efficacy (E_max) of quercetin were 11.8 ± 0.9 μM and 82 ± 2%, while those of fisetin were 38.4 ± 6 μM and 100 ± 6%, respectively. Luteolin (Lute) was a less potent inhibitor of hERG current (48 ± 1% at 100 μM). Galangin, kaempferol, and isorhamnetin (100 μM) showed weaker activity on the hERG currents.ConclusionThese results suggest that quercetin, fisetin, and luteolin are potent hERG K⁺ channel inhibitors and reveal the structure-activity relationship of natural flavonoids.