Bioassay‐guided Evaluation of Antioxidant and Antinociceptive Activities of Carvacrol

Abstract: We examined the antioxidant properties in vitro and the antinociceptive effect of carvacrol (CARV) in several models of pain in mice. CARV presented a strong antioxidant potential according to the TRAP/TAR evaluation; it also presented scavenger activity against nitric oxide and prevented lipid peroxidation in vitro. In mice, when evaluated against acetic acid‐induced abdominal writhing, CARV (25, 50 and 100 mg/kg, i.p.) reduced (p < 0.001) the number of writhing compared to the control group, without opioid participation. In the formalin test, CARV also significantly inhibited both the early (neurogenic pain) and the late (inflammatory pain) phases of formalin‐induced licking, with inhibition percentage values of 56.8% (100 mg/kg) for the neurogenic phase and 41.2% (25 mg/kg), 73.8% (50 mg/kg) and 99.7% (100 mg/kg) for the inflammatory phase. CARV also produced a significant inhibition of the pain caused by capsaicin (63.1, 67.1 and 95.8%, p < 0.001) and glutamate (46.4, 61.4 and 97.9%, p < 0.01). When assessed in a thermal model of pain, CARV (100 mg/kg, i.p.) caused a significant increase (p < 0.05) in the latency response on the hot‐plate test. Such results were unlikely to be provoked by motor abnormality. Together, these results indicate that the properties of CARV should be more thoroughly examined in order to achieve newer tools for management and/or treatment of painful conditions, including those related to pro‐oxidant states.     

Anti-inflammatory and antinociceptive properties of blueberry extract (Vaccinium corymbosum)

Blueberries are among the edible fruits that are recognized best for their potential health benefits. The crude extract from Vaccinium corymbosum was assessed in anti-inflammatory and antinociceptive models. The crude hydroalcoholic extract was administered orally at doses of 100, 200 or 300 mg kg (-1) for all the assays. In the carrageenan test, the crude extract reduced rat paw oedema by 9.8, 28.5 and 65.9%, respectively. For the histamine assay, the reductions of oedema were 70.1, 71.7 and 81.9%, respectively. In the myeloperoxidase (MPO) assay, 300 mg kg (-1) crude extract produced a significant inhibition of the MPO activity, at 6 h and 24 h after injection of carrageenan, by 42.8 and 46.2%, respectively. With the granulomatous tissue assay dexamethasone displayed significant activity, whereas the blueberry extract was inactive. For the abdominal constriction test, inhibitions of 49.0, 54.5, 53.5%, respectively, were observed for the crude extract, and 61.4% for indometacin. In the formalin test, the crude extract (200 and 300 mg kg (-1)) and indometacin inhibited only the second phase by 36.2, 35.3 and 45.8%, respectively. Considering that the crude extract of blueberry displayed antinociceptive and anti-inflammatory activity, its consumption may be helpful for the treatment of inflammatory disorders.     

蔓越莓抗菌作用研究进展

蔓越莓(Vaccinium macrocarpon Ait.)是北美三大水果之一。一直以来,蔓越莓因其预防泌尿道感染的功能而受到广泛关注。大量的研究表明蔓越莓具有抑菌、抗细菌黏附等作用。本综述主要涉及其化学成分、抑菌作用、抗黏附作用及其机制。     

Bioassay‐Guided Isolation and Structural Modification of the Anti‐TB Resorcinols from Ardisia gigantifolia

Tuberculosis (TB) is a highly contagious disease mainly caused by Mycobacterium tuberculosis H₃₇R_V. Antitubercular (anti‐TB) bioassay‐guided isolation of the CHCl₃ extract of the leaves and stems of the medicinal plant Ardisia gigantifolia led to the isolation of two anti‐TB 5‐alkylresorcinols, 5‐(8Z‐heptadecenyl) resorcinol ( 1 ) and 5‐(8Z‐pentadecenyl) resorcinol ( 2 ). We further synthesized 15 derivatives based on these two natural products. These compounds (natural and synthetic) were evaluated for their anti‐TB activity against Mycobacterium tuberculosis H₃₇R_V. Resorcinols 1 and 2 exhibited anti‐TB activity with MIC values at 34.4 and 79.2 μm in MABA assay, respectively, and 91.7 and 168.3 μm in LORA assay, respectively. Among these derivatives, compound 8 was found to show improved anti‐TB activity than its synthetic precursor ( 2 ) with MIC values at 42.0 μm in MABA assay and 100.2 μm in LORA assay. The active compounds should be regarded as new hits for further study as a novel class of anti‐TB agents. The distinct structure–activity correlations of the parent compound were elucidated based on these derivatives.     

Curcumin‐loaded poly(ε‐caprolactone) nanofibres: Diabetic wound dressing with anti‐oxidant and anti‐inflammatory properties

• 1 Curcumin is a naturally occurring poly‐phenolic compound with a broad range of favourable biological functions, including anti‐cancer, anti‐oxidant and anti‐inflammatory activities. The low bioavailability and in vivo stability of curcumin require the development of suitable carrier vehicles to deliver the molecule in a sustained manner at therapeutic levels.
• 2 In the present study, we investigated the feasibility and potential of poly(caprolactone) (PCL) nanofibres as a delivery vehicle for curcumin for wound healing applications. By optimizing the electrospinning parameters, bead‐free curcumin‐loaded PCL nanofibres were developed.
• 3 The fibres showed sustained release of curcumin for 72 h and could be made to deliver a dose much lower than the reported cytotoxic concentration while remaining bioactive. Human foreskin fibroblast cells (HFF‐1) showed more than 70% viability on curcumin‐loaded nanofibres.
• 4 The anti‐oxidant activity of curcumin‐loaded nanofibres was demonstrated using an oxygen radical absorbance capacity (ORAC) assay and by the ability of the fibres to maintain the viability of HFF‐1 cells under conditions of oxidative stress.
• 5 The curcumin‐loaded nanofibres also reduced inflammatory induction, as evidenced by low levels of interleukin‐6 release from mouse monocyte–macrophages seeded onto the fibres following stimulation by Escherichia coli‐derived lipopolysaccharide.
• 6 The in vivo wound healing capability of the curcumin loaded PCL nanofibres was demonstrated by an increased rate of wound closure in a streptozotocin‐induced diabetic mice model.
• 7 These results demonstrate that the curcumin‐loaded PCL nanofibre matrix is bioactive and has potential as a wound dressing with anti‐oxidant and anti‐inflammatory properties.

     

Effect of nanoencapsulation of blueberry (Vaccinium myrtillus): A green source of flavonoids with antioxidant and photoprotective properties

The effect of nanoencapsulation on the in vitro photoprotection and antioxidant properties of blueberry (Vaccinium myrtillus) extract, before and after their dispersion into an oil-in-water emulsion and its final stability under stress conditions. Besides its skin healing activity, chitosan was chosen as wall material due to its natural origin, and possibility of obtention from shrimp residues. Chitosan/tripolyphosphate (TPP) nanoparticles loaded with blueberry extract were produced and characterized. Three different semi-solid oil-in-water emulsions, using Ecocert certified materials, were developed containing, respectively, (i) 5% (wt/wt) of extract-free nanoparticles, (ii) 5% (wt/wt) of extract-loaded nanoparticles, (iii) 2% (wt/wt) of free extract. Sun protection factor (SPF), antioxidant activity and stability under stress conditions were evaluated. The concentration of rutin was determined by High Performance Liquid Chromatography (HPLC). The loading of blueberry extract into nanoparticles kept their physicochemical properties, as well as SPF and antioxidant activity, over the course of the stability study. Extract-loaded nanoparticles were dispersed in a semi-solid oil-in-water emulsion and were shown to protect the extract from oxidation, suggesting that formulation containing 5% (wt/wt) of extract-free nanoparticles could presented lower difference between initial and final SPF and antioxidant activity values after 90 days of analysis. The developed formulation is proposed as a greener potential formulation to be used as photoprotector, especially if associated with physical sun filters. The role of blueberry flavonoids and the synergistic effect of nanoparticles against skin aging are here discussed.     

Synthesis and anti‐Helicobacter pylori properties of NO‐donor/metronidazole hybrids and related compounds

Two series (A, B) of 2‐(2‐methyl‐5‐nitro‐1H‐imidazolyl)ethyl derivatives ( 6–9, 18–23 ) conjugated through an oxygen or an aminomethyl bridge with either a furoxan NO‐donor moiety or a furazan substructure, devoid of NO‐donor properties, were synthesised. A third group (C) of 2‐(2‐methyl‐5‐nitro‐1H‐imidazolyl)ethyl derivatives conjugated with nitrooxy and dinitrooxy NO‐donor functions ( 35, 38 ) as well as the corresponding analogue without these functions ( 40 ) were prepared. All the compounds were evaluated in vitro for their activity against a number of Helicobacter pylori strains. Metronidazole ( 1 ) and its amino analogue ( 11 ) were taken as reference compounds. All the synthesised hybrids and their analogues exhibited good anti‐H. pylori activity with MIC₅₀ in the range less than 0.0039–1, resulting in compounds more active than metronidazole. Derivatives 6–9 displayed good potency also against metronidazole‐resistant strains. Compounds lacking the 5‐nitroimidazole moiety ( 24–29, 30–33 ) proved to be inactive against H. pylori with the exception of 33 . The lack of significant differences in the antibacterial potency between furoxan and furazan hybrids in both series (A, B) suggest that the role of the N‐oxide moiety of the furoxan system either as an inductor of oxidative stress or as a promoter of NO‐donor properties is marginal. The substitution of the furoxan substructures with nitrooxy moieties ( 35, 38 ) afforded active compounds. In view of their NO‐donor properties, NO‐metronidazole hybrids could represent potential therapeutic tools both in the treatment of gastric ulcer and in a number of extragastrointestinal disorders such as ischaemic heart diseases and atherosclerosis‐related to some H. pylori strains. Drug Dev. Res. 60:225–239, 2003. © 2003 Wiley‐Liss, Inc.     

Identification,isolation, and synthesis of seven novel impurities of anti‐diabetic drug Repaglinide

Seven unknown impurities in Repaglinide bulk drug batches at below 0.1% (ranging from 0.05 to 0.10%) were detected by an ultra‐performance liquid chromatographic (UPLC) method. These impurities were isolated from the crude sample of Repaglinide using preparative high performance liquid chromatography (prep‐HPLC). Based on liquid chromatography‐electrospray ionization‐mass spectrometry (LC‐ESI/MS) study, the chemical structures of seven new impurities ( 8 , 9 , 10 , 11 , 13 , 14, and 16 ) were presumed and characterized as 4‐(cyanomethyl)‐2‐ethoxybenzoic acid ( 8) , 4‐(cyanomethyl)‐2‐ethoxy‐N‐(3‐methyl‐1‐(2‐(piperidin‐1‐yl)phenyl)butyl)benzamide ( 9 ), 4‐(2‐amino‐2‐oxoethyl)‐2‐ethoxy‐N‐(3‐methyl‐1‐(2‐(piperidin‐1‐yl)phenyl)butyl) benzamide ( 10 ) and 2‐(3‐ethoxy‐4‐((3‐methyl‐1‐(2‐(piperidin‐1‐yl)phenyl)butyl) carbamoyl) phenyl) acetic acid ( 11) and 4‐(cyanomethyl)‐N‐cyclohexyl‐2‐ethoxybenzamide ( 13) , 2‐(4‐(cyclohexylcarbamoyl)‐3‐ethoxyphenyl) acetic acid ( 14) and N‐cyclohexyl‐4‐(2‐(cyclohexylamino)‐2‐oxoethyl)‐2‐ethoxybenzamide ( 16) . The complete spectral analysis, proton nuclear magnetic resonance (¹H NMR), ¹³C NMR, MS, and infrared (IR) confirmed the proposed chemical structures of impurities. Identification, structural characterization, formation, and their synthesis was first reported in this study. The impurity 11 was crystallized and structure was solved by single crystal X‐ray diffraction. Copyright © 2017 John Wiley & Sons, Ltd.     

MKP‐1 promotes anti‐inflammatory M(IL‐4/IL‐13) macrophage phenotype and mediates the anti‐inflammatory effects of glucocorticoids

Macrophage polarization refers to the ability of these cells to adopt different functional phenotypes according to their environment. Mitogen‐activated protein kinase phosphatase‐1 (MKP‐1) is known to regulate the classical lipopolysaccharide (LPS)‐induced pro‐inflammatory macrophage activation and the inflammatory response. Here, we investigated the effects of MKP‐1 on the anti‐inflammatory and healing‐promoting macrophage phenotype induced by cytokines IL‐4 and IL‐13 and examined the potential mediator role of MKP‐1 in glucocorticoid effects on the two macrophage phenotypes. In MKP‐1‐deficient macrophages treated with IL‐4 and IL‐13 to induce the anti‐inflammatory phenotype, the expression of phenotypic markers arginase 1, Ym‐1 and FGF2 was reduced as compared to wild‐type cells. In contrast, LPS‐induced expression of the pro‐inflammatory factors IL‐6 and iNOS was significantly higher in MKP‐1‐deficient macrophages. Dexamethasone suppressed the pro‐inflammatory phenotype and enhanced the anti‐inflammatory phenotype. Interestingly, both of these glucocorticoid effects were attenuated in macrophages from MKP‐1‐deficient mice. Accordingly, dexamethasone increased MKP‐1 expression in both LPS‐ and IL4+13‐treated wild‐type cells. In conclusion, the findings support MKP‐1 as an endogenous mechanism able to shift macrophage activation from the classical pro‐inflammatory state towards the anti‐inflammatory and healing‐promoting phenotype. In addition, MKP‐1 was found to mediate the anti‐inflammatory effects of dexamethasone in a dualistic manner: by suppressing the pro‐inflammatory macrophage activation and by enhancing the healing‐promoting macrophage phenotype.     

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 and pharmacological evaluation of novel derivatives of anti‐inflammatory drugs with increased antioxidant and anti‐inflammatory activities

The role of reactive oxygen species in inflammatory processes has been well documented, while several antioxidant compounds have been shown to exhibit anti‐inflammatory activity. We designed novel compounds as potential agents that combine enhanced antioxidant and anti‐inflammatory activities. Derivatives of indomethacin, diclofenac, tolfenamic acid, and ibuprofen, four widely used nonsteroidal anti‐inflammatory drugs, with cysteamine, a polar antioxidant molecule, were synthesized. The compounds were evaluated for their effect on free radical processes (protection against rat hepatic microsomal lipid‐peroxidation and interaction with the stable free radical 1,1‐diphenyl‐2‐picrylhydrazyl), as well as on carrageenan‐induced inflammation (mouse paw edema inhibition). Furthermore, ulcerogenicity tests in rats were performed in order to evaluate the gastrointestinal irritation of the novel indomentacin derivative. It was found that all compounds were very potent antioxidants in vitro; they could inhibit lipid peroxidation very significantly, having IC₅₀ values ranging from 55 to 510 μM, while they could also interact ∼90% with DPPH at equimolar concentrations. We attribute these activities to their sulfhydryl group, as well as to their increased lipophilicity compared to cysteamine. Furthermore, the derivatives demonstrated significant anti‐inflammatory activity, comparable to that of the parent molecules, while they showed significantly reduced ulcerogenic potency. Our results indicate that the combined pharmacological properties of these new derivatives may prove useful for the design and development of novel cytoprotective/anti‐inflammatory molecules with potentially important therapeutic applications. Drug Dev. Res. 47:9–16, 1999. © 1999 Wiley‐Liss, Inc.