Search

Antibiotična rezistenca predstavlja vedno bolj pereč problem v sodobnem svetu, ki ga poskušamo reševati z več različnimi ukrepi. Eden izmed njih je tudi iskanjem novih molekul s potencialnim protibakterijskim učinkovanjem. V našem raziskovalnem delu smo se najprej osredotočili na iskanje spojin s potecialnimi protibakterijskimi lastnostmi, ki smo jih opazili pri spojinah s fenidonsko osnovo. Te spojine smo po analizi na difuzijskih antibiogramih nadalje opredelili še na mikrotitrskih ploščah, kjer nas je zanimala odvisnost rasti bakterijskih vrst od koncentracije dodane spojine, kot tudi stopnja inhibicije. Pri delu smo uporabili štiri bakterijske vrste: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus in Bacillus thuringiensis. Tri od teh vrst, E. coli, P. aeruginosa in S. aureus, so pogosti povzročitelji domačih in bolnišničnih okužb pri ljudeh. Ugotovili smo, da se je inhibicija bakterijske rasti v prisotnosti spojin s fenidonsko osnovo zvišala s koncentracijo dodane spojine v kar 8 od 12 primerih, v 6 od 12 primerih pa je tudi stopnja inhibicije znašala več kot 50 %. Naše in podobna raziskovalna dela predstavljajo le majhen začetek pri visoko potencialni rabi različnih spojin pri zdravljenju okužb z omenjenimi bakterijskimi vrstami. Antibiotic resistance represents an increasingly urgent problem in the modern world, which we try to solve with several different measures. One of which is the search for new molecules with potential antibacterial properties. In our research work, we first focused on the search for substances with potential antibacterial properties, which we observed among compounds with a phenidone base. After analyzing these compounds on diffusion antibiograms, we further defined them on microtiter plates, where we were interested in the dependence of the growth of bacterial strains on the concentration of the added compound, as well as the degree of inhibition. In our work we used four bacterial strains: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus thuringiensis. Three of these strains, E. coli, P. aeruginosa and S. aureus, are common causes of community-acquired and nosocomial infections in humans. We found that the inhibition of bacterial growth in the presence of compounds with a phenidone base increased with the concentration of the added compound in as many as 8 out of 12 cases, and in 6 out of 12 cases the degree of inhibition was more than 50 %. Our and similar research works represent only a small beginning in the high potential use of various compounds in the treatment of infections by the mentioned bacterial strains.

Hexanal belongs to green leaf volatiles that function as signal molecules in plants. However, it remains elusive whether and how hexanal functions in herbal medicines besides imparting unique flavor. In this study, the effects of hexanal and Pantoea agglomerans KSC03 on plant growth and secondary metabolism were investigated in medicinal plant Astragalus membranaceus var. mongholicus by treating the seedlings with hexanal, KSC03, and their combination. Biomass yield and the contents of chlorophyll a and b in mature leaves were used as indexes as well as the contents of bioactive isoflavones in the roots. Meanwhile, lipoxygenase (LOX) inhibitor phenidone was applied 48 h before hexanal treatment to obtain the LOXlow seedlings to understand signal roles of LOX pathway in the accumulations of bioactive isoflavones in the roots under hexanal and KSC03 treatments. The results revealed that hexanal alone and its combination with KSC03 significantly increased the shoot and root yields, and hexanal + KSC03 showed stronger promotion on the shoot yield, which coincided with significantly enhanced accumulations of ononin and calycosin-7-O-β-d-glycoside in hexanal + KSC03 treatment. Hexanal + KSC03 also alleviated the detrimental chlorophylls cycle compared with hexanal alone. Except for the combined treatment, phenidone pretreatment greatly enhanced the concentrations of ononin and calycosin-7-O-β-d-glycoside in the roots of the control and the application of hexanal and KSC03 alone. In conclusion, hexanal + KSC03 treatment was more beneficial on plant growth and accumulations of bioactive isoflavones in the roots of A. membranaceus var. mongholicus, partially due to the attenuated inhibition of LOX signaling.

Many studies have shown that virus infection alters phytohormone signaling and insect vector contact with hosts. Increased vector contact and movement among plants should increase virus survival and host range. In this study we examine the role of virus-induced changes in phytohormone signaling in plant-aphid interactions, using Pea enation mosaic virus (PEMV), pea aphids (Acyrthosiphon pisum), and pea (Pisum sativum) as a model. We observed that feeding by aphids carrying PEMV increases salicylic acid and jasmonic acid accumulation in pea plants compared to feeding by virus-free aphids. To determine if induction of the oxylipin jasmonic acid is critical for aphid settling, attraction, and retention on PEMV-infected plants, we conducted insect bioassays using virus-induced gene silencing (VIGS), an oxylipin signaling inducer, methyl jasmonate (MeJA), and a chemical inhibitor of oxylipin signaling, phenidone. Surprisingly, there was no impact of phenidone treatment on jasmonic acid or salicylic acid levels in virus-infected plants, though aphid attraction and retention were altered. These results suggest that the observed impacts of phenidone on aphid attraction to and retention on PEMV-infected plants are independent of the jasmonic acid and salicylic acid pathway but may be mediated by another component of the oxylipin signaling pathway. These results shed light on the complexity of viral manipulation of phytohormone signaling and vector-plant interactions.

The present study was designed to evaluate the effects of phenidone (Dual inhibitor of COX-2 and 5-LOX, DuCLOX-2/5 inhibitor) on various aspects of cancer chemoprevention. Treatment with the phenidone was inquested to validate the implications of dual inhibition of arachidonic acid (AA) metabolism against MNU induced mammary gland carcinogenesis. MNU treated rat showed altered hemodynamic profile, distorted cellular architecture, upregulated inflammatory enzyme markers (COX, LOX, Nitric oxide and hydrogen sulfide) and distorted oxidative stress markers (thiobarbituric acid reactive substances, protein carbonyl, superoxide dismutase, catalase and glutathione). Phenidone treatment regulated histological architecture in the experimental animals similar to control. The treatment with phenidone favorably regulated the levels of inflammatory markers, and oxidative stress markers against toxic treatment. Our findings emphasize the potential role of phenidone in suppression of mammary gland carcinoma against the deleterious effects of MNU.

Eicosandoids, or icosanoids, are signaling compounds created by the oxidation of 20-carbon fatty acids. They control many complex physiological and immunological functions in vertebrate and invertebrate animals. This study tested the hypothesis that eicosanoids act in insect antioxidant defense. The effects of 3 eicosanoid biosynthesis inhibitors (EBIs) - dexamethasone, esculetin, and phenidone - on the oxidative stress indicator, malondialdehyde (MDA), and the detoxification enzyme, glutathione S-transferase (GST), was examined in the midgut of larvae of the greater wax moth, Galleria mellonella (L). The larvae were reared on artificial diets supplemented with 0.001, 0.01, 0.1 or 1.0% of the EBIs. Esculetin, which is a lipoxygenase inhibitor, significantly increased MDA content; whereas, GST activity was significantly increased at only the highest concentration tested. Dexamethasone, a phospholipase A2 inhibitor, significantly increased MDA content and GST activity at concentrations of 0.01, 0.1, and 1.0%. Phenidone, a dual inhibitor of cyclooxygenase and lipoxygenase, increased MDA content, whereas the 0.01 and 0.1% concentrations of phenidone significantly increased GST activity. Our results indicate that antioxidative responses are, at least in part, controlled by a physiological system that includes eicosanoid biosynthesis.

Mepivacaine is an aminoamide local anesthetic with an intermediate duration that intrinsically produces vasoconstriction both in vivo and in vitro. This study investigated the arachidonic acid metabolic pathways involved in mepivacaine-induced contraction, and elucidated the associated cellular mechanism with a particular focus on extracellular signal-regulated kinase (ERK) in endothelium-denuded rat aorta. Isolated rat thoracic aortic rings were suspended for isometric tension recording. Cumulative mepivacaine concentration–response curves were generated in the presence or absence of the following inhibitors: quinacrine dihydrochloride, nordihydroguaiaretic acid, phenidone, AA-861, indomethacin, NS-398, SC-560, fluconazole, PD 98059, and verapamil. Mepivacaine-induced ERK phosphorylation, 5-lipoxygenase (5-LOX) expression, and cyclooxygenase (COX)-2 expression in rat aortic smooth muscle cells were detected by Western blot analysis in the presence or absence of inhibitors. Mepivacaine produced tonic contraction in isolated endothelium-denuded rat aorta. Quinacrine dihydrochloride, nordihydroguaiaretic acid, phenidone, AA-861, NS-398, PD 98059, and verapamil attenuated mepivacaine-induced contraction in a concentration-dependent manner. However, fluconazole had no effect on mepivacaine-induced contraction. PD 98059, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, and indomethacin attenuated mepivacaine-induced ERK phosphorylation. Mepivacaine upregulated 5-LOX and COX-2 expression. These results suggest that mepivacaine-induced contraction involves ERK activation, which is primarily mediated by the 5-LOX pathway and in part by the COX-2 pathway.

We posed the hypothesis that inhibition of eicosanoid biosynthesis leads to increased lipid peroxidation in insects. Here we report that rearing the greater wax moth, Galleria mellonella, on media supplemented with selected inhibitors of eicosanoid biosynthesis throughout the larval, pupal and adult life led to major alterations in selected oxidative and antioxidative parameters of wax moth and its ectoparasitoid, Bracon hebetor. The highest dietary dexamethasone (Dex), esculetin (Esc) and phenidone (Phe) led to increased malondialdehyde (MDA) levels and to elevated catalase (CAT) and glutathione-S-transferase (GST) activities in all developmental stages of host larvae. Dietary Phe resulted in increased MDA levels, and CAT activity in G. mellonella adults by about 4-fold and about 2-fold, respectively. The Phe effect on GST activity in all stages of the wax moth was expressed in a dose-dependent manner, increased to 140 nmol/mg protein/min in larvae. MDA levels were increased by over 30-fold in adult wasps reared on Dex- and Esc-treated hosts. CAT and GST activities were increased in adult parasitoids reared on Esc-and Phe-treated hosts. GST activity of Dex-treated parasitoid larvae increased from about 4 to over 30 nmol/mg protein/min. Dietary Phe led to increased GST activity, by about 25-fold, in adult wasps. These data indicate that chronic inhibition of eicosanoid biosynthesis leads to increased oxidative stress, strongly supporting our hypothesis. The significance of this work lies in understanding the roles of eicosanoids in insect biology. Aside from other well-known eicosanoids actions, we propose that eicosanoids mediate reductions in oxidative stress. © 2016 Elsevier Inc.

This paper shows that the diffraction efficiency is influenced by superadditivity for the combination of the different developing agent and concentrations in the reversal bleach applied to the Slavich PFG-01 plate to be used for recording transmission holograms. The four developers based on ascorbic acid in combination with metol, phenidone, hydroquinone respectively, were studied. In diffraction efficiency aspect, the superadditivity effect of mixture of two developing agents is lower than one developing agent developer, AAC in the reversal bleach.

One of the strategies that plants employ to defend themselves against herbivore attack is the induced production of carnivore-attracting volatiles. Using elicitors and inhibitors of different steps of the signal-transduction pathways can improve our understanding of the mechanisms underlying induced plant defenses. For instance, we recently showed that application of jasmonic acid, a key hormone in the octadecanoid pathway involved in herbivore-induced defense, to Brassica oleracea affects gene expression, hormone levels, and volatile emission, as well as oviposition by herbivores and host location behavior by parasitoids. Such defense responses vary with the dose of the elicitor and with time since application. This addendum describes how the use of inhibitors, in addition to the use of elicitors like jasmonic acid, can be applied in bio-assays to investigate the role of signal-transduction pathways involved in induced plant defense. We show how inhibition of different steps of the octadecanoid pathway affects host location behavior by parasitoids.

Nodulation is the predominant cellular defense reaction to bacterial challenges in insects. In this study, third instar larvae of Chrysomya megacephala were injected with bacteria, Escherichia coli K 12 (106 CFU/mL, 2 μL), immediately prior to injection of inhibitors of eicosanoid biosynthesis, which sharply reduced nodulation response. Test larvae were treated with specific inhibitors of phospholipase A2 (dexamethasone), cyclo-oxygenase (indomethacin, ibuprofen and piroxicam), dual cyclo-oxygenase/lipoxygenase (phenidone) and lipoxygenase (esculetin) and these reduced nodulation except esculetin. The influence of bacteria was obvious within 2 h of injection (5 nodules/larva), and increased to a maximum after 8 h (with 15 nodules/larva), and then significantly reduced over 24 h (9 nodules/larva). The inhibitory influence of dexamethasone was apparent within 2 h of injection (4 vs. 5 nodules/larva), and nodulation was significantly reduced, compared to control, over 24 h (5 vs. 8 nodules/larva). Increased dosages of ibuprofen, indomethacin, piroxicam and phenidone led to decreased numbers of nodules. Nodules continued to exist during the pupal stage. However, the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid. These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. megacephala.

Nodulation is the temporally and quantitatively most important cellular defense response to bacterial, fungal and some viral infections in insects. We tested the hypothesis that prostaglandins and other eicosanoids are responsible for mediating nodulation reactions to bacterial infection in larvae of the blowfly Chrysomya megacephala. Third-instar larvae treated with Ureaplasma urealyticum formed nodules in a challenge dose-dependent manner. Nodulation was evoked shortly after injection and reached a maximum of approximately 25 nodules/larva within 8 h. Larvae treated with the glucocorticoid, dexamethasone and the cyclooxygenase inhibitors, indomethacin and piroxicam were impaired in their ability to form nodules following U. urealyticum infection. The number of nodules decreased with increasing doses of piroxicam. Contrarily, treating larvae with the lipooxygenase inhibitor, esculetin, and the dual cyclooxygenase/lipooxygenase inhibitor, phenidone did not influence nodulation reactions to infection. Supplying dexamethasone-treated larvae with the eicosanoid precursor, arachidonic acid, reversed the inhibitory effect of dexamethasone on nodulation. We infer from these results that eicosanoids mediate nodulation reactions to infection of a bacterial species that lacks cell walls in larvae of the blowfly, C. megacephala.

The effects of developing agents and activators in the reversal bleach upon the diffraction efficiencies of a Slavich PFG-01 plate to be used for recording transmission holograms were studied. The plates were developed using four different developers: MSC, AAC, PSC, and HSC. The four developers were derived from different developing agents of metol, l-ascorbic acid, phenidone, and hydroquinone, respectively. Sodium carbonate was added to the developer as an activator that accelerates the development by keeping the developer alkaline. A maximum diffraction efficiency of 89.0% was obtained when the AAC developer was used.

Antioxidant activities of pure chemicals and food additives were compared with that of herb extracts using a method based on the Fenton reaction for screening natural antioxidants. This method detects antioxidants classified as free radical terminators, that may compete with linoleic acid for scavenging OH radicals. Of the 39 products investigated, 19 were commercial products and 20 were aqueous and ethylic herb infusions. Commercial phenolic and flavonoid products, both hydrophilic and lipophilic, showed strong antioxidant activities, while indole, alkaloid and fs-cyclic products showed no antioxidant activity, as determined by this method. Aqueous infusions of all herbs showed antioxidant properties. Mild oregano, strong oregano, rosemary, sage and mint showed as strong antioxidant properties as pure commercial chemical and food additives, such as hydroquinone, rutin, phenidone, catechol, epicatechin, morin and BHA, in both aqueous and ethylic infusions. Also, the results suggest that, under the experimental conditions, the aqueous extractions of short duration yielded larger quantities of active compounds by reducing the degradation of their antioxidant properties.

Previously unknown 2-methoxy(or ethoxy)-4-(11-oxo-9-phenyl-7,8,9,10,11,12-hexahydrobenzo[b][4,7]phenanthrolin-12-yl)phenyl esters of carboxylic acids were prepared by ternary condensation of vanillin or vanillal alkanoates with 6-quinolylamine and Phenidone. According to the 1H NMR spectra, the target products are formed as mixtures of diastereomers.

This paper shows that the diffraction efficiency is influenced by superadditivity for the combination of the different developing agent and concentrations in the reversal bleach applied to the Slavich PFG-01 plate to be used for recording transmission holograms. The four developers based on ascorbic acid in combination with metol, phenidone, hydroquinone respectively, were studied. In diffraction efficiency aspect, the superadditivity effect of mixture of two developing agents is lower than one developing agent developer, AAC in the reversal bleach.

The role of lipoxygenase (LOX) in the elicitor-induced taxol production of Taxus chinensis cell cultures was studied. Fungal elicitor F 5 treatment effectively increased LOX activity and taxol production. The LOX activity inhibitor phenidone could inhibit induced LOX activity and taxol production, suggesting that LOX pathway might be involved in elicitor-induced taxol production. Methyl jasmonate (MJ) also activated LOX activity and taxol production. Phenidone could inhibit LOX activity and taxol production challenged by MJ, suggesting that exogenous MJ may induce taxol production via activating the intracellular LOX pathway. For better understanding the role of LOX in T. chinensis , some biochemical features of LOX were also investigated. Results showed that at least 49.18% LOX was associated with membrane and the molecular weight of LOX was 93 kDa.

A simple and fast micellar electrokinetic chromatographic (MEKC) method for the determination of five main compounds (hydroquinone, metol, phenidone, 2-hydroxy-5-methylaminobenzenesulphonate and 2,5-dihydroxybenzenesulphonate) in X-ray film developing solutions was developed. The optimal conditions for the separation were established by varying the concentration of sodium dodecyl sulfate (SDS), the electrolyte pH and the temperature. Successful results were obtained with a 25 mmol L−1 Tris-phosphate buffer at pH 9.0 in the presence of 50 mmol L−1 SDS using direct UV detection at 214 nm. Under these conditions, baseline separation of the five compounds was achieved in less than 8 min. The method was validated in terms of precision, linearity, accuracy, and successfully applied to the analysis of X-ray film developing baths.

Phase holograms processed with a reversal bleaching is considered to have lower diffraction efficiency than those processed with other bleaching methods. The high diffraction efficiency could also be obtained in the reversal bleach under the adjustment of developer component. This paper shows that must have been optimized the type and the concentration of developer component in order to obtain the high diffraction efficiency. Experiments were carried out with Slavich PFG-01 plates on the processing of transmission holograms and the four types developer used with reversal bleach. The developer is composed of 1-ascorbic acid, metol, phenidone, and sodium carbonate contained with different amounts. The maximum diffraction efficiency of 89% was obtained.

This study aimed to investigate the anti-inflammatory activity of (E)-1-(3,4-dimethoxyphenyl) butadiene (DMPBD), isolated from Zingiber cassumunar Roxb., using in vivo and in vitro models. The results show that DMPBD dose-dependently inhibited the rat ear edema induced by ethyl phenylpropiolate (EPP), arachidonic acid (AA) and 12-O-tetradecanoylphorbol 13-acetate (TPA) and it was more potent than any other standard drugs being used. In EPP-induced edema IC(50) of DMPBD and oxyphenbutazone were 21 and 136nmol per ear, respectively. The IC(50) of DMPBD and phenidone were 60 and 2520nmol per ear, respectively, in AA-induced edema whereas DMPBD was 11 times more potent than diclofenac in TPA-induced edema (IC(50)=660 and 7200pmol per ear, respectively). DMPBD and diclofenac inhibited the rat paw edema induced by carrageenan but not by platelet activating factor (PAF). In in vitro study DMPBD, aspirin and phenidone inhibited collagen-induced platelet aggregation with IC(50) of 0.35, 0.43 and 0.03mM, respectively. Whereas IC(50) of these agents in ADP, AA and PAF inductions were 4.85, 3.98 and 1.30mM; 0.94, 0.13 and 0.04mM; and 1.14, 6.96 and 2.40mM, respectively. These results indicate that DMPBD possesses a potent anti-inflammatory activity through the inhibition of CO and LO pathways and seems to have more prominent effects on the LO pathway.

12-Lipoxygenase (12-LO) has been shown to be a factor in acute ischemic preconditioning (IPC) in the isolated rat heart; however, no studies have been reported in delayed PC. We characterized the role of 12-LO in an intact rat model of delayed PC induced by a δ-opioid agonist SNC-121 (SNC). Rats were pretreated with SNC and allowed to recover for 24 hours. They were then treated with either baicalein or phenidone, 2 selective 12-LO inhibitors. In addition, SNC-pretreated rats had plasma samples isolated at different times after ischemia-reperfusion for liquid chromatographic–mass spectrometric analysis of the major metabolic product of 12-LO, 12-HETE. Similar studies were conducted with inhibitors. Gene array data showed a significant induction of 12-LO message ( P P

Metarhizium anisopliae conidia (spores) reduced weight gain and caused death when injected into Manduca sexta larvae. When the fungus was co-injected with the eicosanoid biosynthesis inhibitor dexamethasone, larval weight gain was further reduced and mortality increased. These effects were reversed when dexamethasone was given together with the eicosanoid precursor arachidonic acid (AA). Similarly, treatment with other eicosanoid biosynthesis inhibitors (esculetin, phenidone, ibuprofen, and indomethacin) with differing modes of action enhanced the reduction in weight gain caused by mycosis. Injection of M. anisopliae conidia induced nodule formation in vivo; nodule numbers were reduced by dexamethasone, and restored by AA. Incubation of hemocytes with conidia caused microaggregation of hemocytes (indicative of nodule formation) in vitro and this was inhibited by dexamethasone, suggesting that dexamethasone acts directly on hemocytes, although inhibition was only partially reversed by AA. We suggest that the M. sexta immune response to fungal pathogens is normally modulated by physiological systems that include eicosanoid biosynthesis. This is the first demonstration that the virulence of a fungal entomopathogen can be enhanced by compromising the insect host's immune system.

Photoinitiated chemical reduction of AgBr nanocrystals (synthesized in water pools of reverse micelles of Aerosol OT and sodium dodecyl sulfate) with phenidone was shown to yield 1-phenyl-3-hydroxypyrazole along with reduced silver. This becomes possible because of irreversible oxidation of phenidone (1-phenyl-3-pyrazolidone) used as a reducing agent, and the rate of 1-phenyl-3-hydroxypyrazole accumulation significantly increases in the presence of a silver halogenide. The formation of the dissociated form of 1-phenyl-3-hydroxypyrazole becomes more probable with decreasing diameter of the water pool of reverse micelles formed by both surfactants.

Effluents from X-ray film developing processes feature high contaminant load (COD about 200 g/l). Identification of the main organics present in these wastewaters was performed by using liquid chromatography-mass spectrometry in electron impact mode, LC-(EI)MS. Both, unconsumed ingredients and sulphonated/hydroxylated derivatives and dimers yielded from the developing agents hydroquinone and phenidone were found to be the main organics contributing to the contaminant load of these effluents. Their potential degradation by oxidation with both photo- and thermal-Fenton reactions was investigated and the optimal degradation conditions were determined. Under these conditions the initial COD was reduced by about 97% within 6 h of treatment. The intermediates detected by LC-(EI)MS in the oxidation of hydroquinone and phenidone during the treatment were essentially hydroxylated derivatives and dimers and the residual organic matter was mainly made up of carboxylic acids. Reaction pathways for the oxidation of the developing agents hydroquinone and phenidone were proposed. The presence of many organic and inorganic components in the wastewaters did not affected the favoured oxidation route of these developers. The results obtained allow to assess the reduction of costs permitted in the treatment of X-ray effluents with the photo- and thermal-Fenton reaction without affecting the degradation degree and quality of the discharge.

Nodulation is the first, and qualitatively predominant, cellular defense reaction to bacterial infections in insects. We tested the hypothesis that eicosanoids also mediate nodulation reactions to bacterial challenge in adults of a social insect, the honey bee, Apis mellifera. Treating newly-emerged experimental bees with the eicosanoid biosynthesis inhibitor, dexamethasone, impaired nodulation reactions to bacterial infections, and the influence of dexamethasone was reversed by treating infected insects with arachidonic acid, an eicosanoid precursor. Several other eicosanoid biosynthesis inhibitors, including the cyclooxygenase inhibitor, indomethacin, and the dual cyclooxygenase/lipoxygenase inhibitor, phenidone, also impaired the ability of experimental honeybees to form nodules in reaction to bacterial challenge. The influence of phenidone on nodulation was expressed in a dose-dependent manner. However, in experiments with older honey bees foragers, similar bacterial challenge did not evoke nodulation reactions. We infer from our results that while eicosanoids mediate cellular immune responses to bacterial infections in newly emerged honey bees, and more broadly, in most insect species, nodulation reactions to bacterial challenge probably do not occur in all phases of insect life cycles.

N-Aminoindoline derivatives were prepared and their 5-lipoxygenase inhibitory activities were evaluated in vitro and compared with those of phenidone and NDGA. Compound 4 presents the most effective 5-LO inhibition.

The effects of the second-generation leukotriene B 4 receptor (LTB 4 receptor) antagonist, 2-[2-propyl-3-{3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxy-phenoxy]-propoxy}phenoxy]benzoic acid sodium salt (LY293111Na), on leukotriene B 4 -induced leukocyte infiltration and interleukin-1-accelerated collagen-induced arthritis in mice were studied. Neutrophil infiltration induced into an air pouch by leukotriene B 4 was dose-dependently inhibited by LY293111Na and strongly so by another LTB 4 receptor antagonist, 4-[5-{4-(aminoiminomethyl)phenoxy}pentoxy]-3-methoxy- N , N -bis(1-methylethyl) ( Z )-2butenedioate (1:1) (CGS25019C). Both compounds significantly inhibited the increase of the arthritis index and the ankle bone destruction in interleukin-1-accelerated collagen-induced arthritis. Phenidone, a 5-lipoxygenase inhibitor, also inhibited interleukin-1-accelerated collagen-induced arthritis, while indomethacin and tenidap, cyclooxygenase inhibitors, had slight inhibitory effects. Injection of interleukin-1 elicited a marked increase of the leukotriene B 4 level in arthritic paws, while the prostaglandin E 2 level was slightly increased. These findings indicate clearly that leukotriene B 4 is an important mediator of interleukin-1-accelerated collagen-induced arthritis in mice. If this can be extrapolated to man, LTB 4 receptor antagonists might be useful for treatment of the acute progressive phase of human arthritis.

Acculmulating evidence indicates that a marked generation of oxygen free radicals derived from the metabolism of arachidonic acid causes neurodegeneration. Recently, we have demonstrated that the novel antioxidant actions mediated by phenidone, a dual inhibitor of cyclooxygenase/lipoxygenase pathways, may play a crucial role in preventing neuroexcitotoxicity in vitro [Neurosci. Lett. 272 (1999) 91], and that phenidone significantly attenuates kainic acid (KA)-induced seizures via inhibiting the synthesis of Fos-related antigen protein [Brain Res. 782 (1998) 337]. In order to extend our understanding of the pharmacological intervention of phenidone, we evaluated the antioxidant activity of this compound in vivo in the present study. In order to better understand the significance of a blockade of both the cyclooxygenase and lipoxygenase pathways, we studied the effects of aspirin (ASP; a non-selective inhibitor of cyclooxygenase), NS-398 (a selective inhibitor of cyclooxygenase-2), esculetin (an inhibitor of lipoxygenase) and phenidone on lipid peroxidation, protein oxidation, and glutathione (GSH) status in the rat hippocampus after KA administration. ASP (7.5 or 15 mg/kg), NS-398 (10 or 20 mg/kg), esculetin (5 or 10 mg/kg) or phenidone (25, 50 or 100 mg/kg) was administered orally five times every 12 h before the injection of KA (10 mg/kg, i.p.). The KA-induced toxic behavioral signs, oxidative stress (lipid peroxidation and protein oxidation), impairment of GSH status, and the loss of hippocampal neurons were dose-dependently attenuated by the phenidone, NS-398+esculetin, and ASP+esculetin. However, ASP, NS-398 and esculetin alone failed to protect against the neurotoxicities induced by KA. Therefore, the results suggest that protection by blockade of both cyclooxygenase and lipoxygenase pathways against KA-induced neuroexcitotoxicity is via antioxidant actions. However, a novel anticonvulsant/neuroprotective effect mediated by phenidone remains to be further characterized.

Prostaglandin levels were determined by fluorometric HPLC analysis of hemolymph collected from larvae of the true armyworm, Pseudaletia unipuncta, that had been injected with bacteria. Prostaglandins were extracted and derivatized with the fluorogenic compound 9-anthryldiazomethane and detected by fluorescence-HPLC. One of the prostaglandins produced was identified as prostaglandin F2a based on HPLC retention time. The chemical identity of prostaglandin F2a was confirmed by isolation and derivatization followed by gas chromatography mass spectrometry analysis. Larvae injected with heat-killed bacteria, Serratia marcescens, produced about 4 times as much prostaglandin F2a as larvae injected with saline. In a separate experiment, larvae injected with bacteria and the prostaglandin precursor arachidonic acid produced still higher levels of prostaglandin F2a. The production of prostaglandin was inhibited with phenidone, a dual cyclooxygenase and lipoxygenase inhibitor. These data indicate that bacterial injections stimulate increased eicosanoid biosynthesis in true armyworms, particularly biosynthesis of prostaglandin F2a. Our findings add considerable support to the hypothesis that eicosanoids mediate insect cellular immune reactions to bacterial infections. Arch. Insect Biochem. Physiol. 41:225‐232, 1999. © 1999 Wiley-Liss, Inc.

This study investigates the effect and some of the mechanisms involved following systemic treatment of mice with Mycobacterium bovis bacillus Calmette-Guerin (BCG) (1 dose per animal containing 6.4 x 10(4) colony-forming units (CFu) 20-60 days beforehand) on modulation of the kinin B1 receptor agonist-induced nociception and oedema formation in the formalin test. Intraplantar (i.p.l.) co-injection of des-Arg9-bradykinin (4-32 nmol/paw) or des-Arg10-kallidin (1-15 nmol/paw), together with sub-maximal concentrations of formalin (0.01 or 0.5%), potentiated (P < 0.01) both pain phases and the paw oedema caused by formalin in animals pre-treated with saline. However, when animals were pre-treated with BCG, the dose-response curves for both B1 agonists were shifted 2 to 8-fold to the left. These B1-mediated effects peaked at 30-45 days after BCG treatment and were still elevated at 60 days after BCG injection. The pain response and oedema formation caused by i.p.l. co-injection of des-Arg9-bradykinin, together with formalin in BCG-pre-treated animals, were dose-dependently antagonised by i.p.l. co-injection of the B1 antagonist des-Arg9[Leu8]bradykinin (1-15 nmol/paw), but were not affected by the B2 antagonist Hoe 140 (10 nmol/paw). The i.p.l. co-injection of tyrosine8-bradykinin (a B2 agonist, 3-15 nmol/paw) with formalin (0.01 or 0.5%) potentiated the pain response and paw oedema in BCG and saline-pre-treated animals to the same extent (P < 0.01). The actions caused by tyrosine8-bradykinin were antagonised by Hoe 140, while des- Arg9[Leu8]bradykinin (10 nmol/paw) had no effect. Dexamethasone (0.5 mg/kg, s.c.), given every 24 h, from day 0 to 30-45, inhibited significantly the potentiation of nociceptive response and oedema formation caused by i.p.l. co-injection of formalin plus des-Arg9-bradykinin, while indomethacin (2 mg/kg, i.p.) or phenidone (30 mg/kg, i.p.), given 1 h prior, caused less inhibition. These data show that the long-term systemic treatment of mice with BCG produced dose-related potentiation of B1 receptor agonist-mediated nociception and oedema formation, without affecting similar responses caused by the B2 receptor agonist tyrosine8-bradykinin. Thus, systemic treatment of mice with BCG induces upregulation of B1 receptors, without affecting B2-mediated responses, by a mechanism that seems to be secondary to cytokine release.

Several studies have described metabolism of pesticidal chemicals in plants and animals by the NADPH-dependent cytochrome P-450 monooxygenases while relatively little is known regarding the role played by the peroxidative oxidation pathway. Here we describe, for the first time, hydrogen peroxide-supported N-demethylation of aminocarb by the highly purified preparations of soybean lipoxygenase. Formaldehyde generated in the reaction was estimated by the Nash reaction. N-demethylation of aminocarb was found to depend on the incubation time, concentration of the enzyme, aminocarb, and hydrogen peroxide. Under optimal conditions,Vmaxvalues of 18 nmol of formaldehyde/min/nmol of lipoxygenase or 170 nmol of formaldehyde/min/mg protein were observed. The reaction exhibitedKmvalues of 3.4 mM for aminocarb and 235 μM for hydrogen peroxide. A strong inhibition of the reaction by nordihydroguaiaretic acid, gossypol, and phenidone clearly implicates the lipoxygenase involvement as the protein catalyst. A significant decline in the formaldehyde accumulation in the presence of either reduced glutathione or dithiothreitol suggests generation of a free radical species as an initial oxidation intermediate during the demethylation of aminocarb by the lipoxygenase. The inhibition of formaldehyde generation by BHT and BHA further supports this contention. In addition to aminocarb, seven other pesticides were also found to undergo N-demethylation, albeit at relatively low rates. Collectively, the evidence presented suggests, for the first time, that certain pesticides may oxidatively undergo dealkylation via the lipoxygenase pathway in plants.

Whole-cell patch-clamp recordings were used to investigate the effects of arachidonic acid (AA) on K+ and Ca2+ channels in isolated rat type I carotid body cells. AA (2-20 microM) produced a concentration-dependent inhibition of both K+ currents and Ca2+ channel currents. The effects of AA on K+ currents were unaffected by indomethacin (5 microM), phenidone (5 microM) or 1-aminobenzotriazole (3 mM), suggesting that AA did not exert its effects via cyclo-oxygenase, lipoxygenase or cytochrome P-450 (cP-450) metabolism. Our results suggest that AA directly and non-selectively inhibits ionic currents in rat type I carotid body cells.

Vasoconstriction induced by dexmedetomidine, a highly selective alpha-2 adrenoceptor agonist, mainly involves c-Jun NH2 -terminal kinase (JNK) phosphorylation in the isolated endothelium-denuded aorta. We carried out an in vitro study to determine the main arachidonic acid metabolic pathway that is involved in dexmedetomidine-induced JNK activation. Cumulative dexmedetomidine concentration-contractile response curves were generated in the endothelium-denuded rat aorta in the presence or absence of the following inhibitors: the JNK inhibitor SP600125, the phospholipase A2 inhibitor quinacrine dihydrochloride, the non-specific lipoxygenase (LOX) inhibitor nordihydroguaiaretic acid, the 5-LOX inhibitor AA-861, the dual 5-LOX and cyclooxygenase (COX) inhibitor phenidone, the non-specific COX inhibitor indomethacin, the cytochrome p450 epoxygenase inhibitor fluconazole, the COX-1 inhibitor SC-560, and the COX-2 inhibitor NS-398. The effect of the alpha-2 adrenoceptor inhibitor rauwolscine and other inhibitors, such as quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, indomethacin and the protein kinase C inhibitor GF 109203X, on dexmedetomidine-induced JNK phosphorylation was investigated in rat aortic vascular smooth muscle cells with western blotting. The effect of dexmedetomidine on 5-LOX and COX-2 expression was investigated in vascular smooth muscle cells. SP600125, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, rauwolscine and chelerythrine attenuated dexmedetomidine-induced contraction. Indomethacin slightly attenuated dexmedetomidine-induced contraction. Fluconazole and SC-560 had no effect on dexmedetomidine-induced contraction, whereas NS-398 attenuated contraction. SP600125, rauwolscine, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone and GF 109203X attenuated dexmedetomidine-induced JNK phosphorylation. 5-LOX and COX-2 were upregulated by dexmedetomidine. Thus, dexmedetomidine-induced alpha-2 adrenoceptor-mediated contraction is mediated mainly by 5-LOX and partially by COX-2, which leads to JNK phosphorylation.

The electron paramagnetic resonance (EPR) spectra of gamma-irradiated single crystals of phenidone (fenidon C9H10N2O) have been studied for different orientations of crystals in a magnetic field. Phenidone single crystals have been irradiated with Co-60-gamma rays at room temperature. The EPR spectra have been investigated at temperatures between 125 and 450 K. The spectra have been found to be temperature independent. The spin-Hamiltonian parameters have been obtained from the single-crystal EPR analysis. The principal values of the hyperfine coupling tensor of the unpaired electron and the principal values of the g-tensor have been determined.

The electron paramagnetic resonance (EPR) spectra of gamma-irradiated single crystals of phenidone (fenidon C9H10N2O) have been studied for different orientations of crystals in a magnetic field. Phenidone single crystals have been irradiated with 60Co-γ rays at room temperature. The EPR spectra have been investigated at temperatures between 125 and 450 K. The spectra have been found to be temperature independent. The spin-Hamiltonian parameters have been obtained from the single-crystal EPR analysis. The principal values of the hyperfine coupling tensor of the unpaired electron and the principal values of the g-tensor have been determined. © 2013 Taylor & Francis.

1. The effects of the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA) on the ionic currents of rat carotid body type I cells were investigated by use of whole-cell and outside-out patch clamp techniques. 2. NDGA (5-50 microM) produced a concentration-dependent inhibition of whole-cell K+ currents at all activating test potentials (holding potential -70 mV). The time-course of the inhibition was also concentration-dependent and the effects of NDGA were only reversible following brief periods of exposure (

The contribution of several vasoactive mediators such as histamine, serotonin, bradykinin, arachidonic acid metabolites and PAF to vascular permeability changes was determined in a rat model of acute endotoxemia. Lipopolysaccharide (10–40 mg/kg, i.v.) from E. coli 0127:138 (LPS) elicited an increase in Evans blue extravasation in trachea, thymus, seminal vesicle and stomach, whereas other organs remained unaffected. LPS (25 mg/kg)-induced extravasation was not inhibited by intravenous pretreatment with histamine (H1) antagonist mepyramine (5 mg/kg) or bradykinin (B2) antagonist HOE-140 (0.1 mg/kg), whereas other standard drugs selectively inhibited leakage in particular tissues, e.g. the cyclooxygenase inhibitor indomethacin (5 mg/kg) in trachea (78%) and seminal vesicle (64%), the serotonin and H1 antagonist cyproheptadine (2 mg/kg) in trachea (88%) and stomach (56%) and the dual cyclooxygenase/lipoxygenase inhibitor phenidone (10 mg/kg) in seminal vesicle (87%). PAF antagonists lexipafant and UR-12460 (10 mg/kg), but not apafant, potently inhibited extravasation in trachea (59, 84%) and seminal vesicle (81, 78%) and in stomach only UR-12460 (52%), whereas all of them were ineffective in thymus. When extravasation was induced by PAF (4 μg/kg) a low dose (0.1 mg/kg) of the three PAF antagonists strongly reduced extravasation in thymus and seminal vesicle, whereas lexipafant and UR-12460 did so in trachea (82, 100%) and only lexipafant in stomach (100%). Mepyramine, cyproheptadine, HOE-140 and indomethacin did not inhibit the effect of PAF, whereas phenidone inhibited it by 58% in trachea. These results suggest that most of the LPS-induced increase in vascular permeability is mediated by secondary vasoactive mediators among which PAF plays a pivotal role, although their relative contribution may vary from tissue to tissue.

In this study, lipoxygenase from potato tuber has been purified by a method involving hydrophobic chromatography and the purified enzyme immobilized by covalent coupling to oxirane acrylic beads. The immobilized lipoxygenase exhibited increased long-term stability without a significant modification of the kinetic parameters. The comparative study on the effects of inhibitors such as dithizone, NDGA, phenidone, and beta-mercaptoethanol on the free and immobilized enzyme highlighted the importance of the lipoxygenase--support interaction, concluding that the immobilization process could cause the protection of the iron atom in the enzyme. The enzymatic specificity was maintained for the immobilized lipoxygenase, and their stability increased as compared to the free enzyme, making if feasible to use the enzyme in a multistep reaction to produce large quantities of leukotriene A4 or other related compounds of interest in the chemical industry and medicine.

We have reported that bradykinin induces graded contraction in guinea-pig gallbladder in vitro through activation of bradykinin B2 receptors and prostanoid release, while des-Arg9-bradykinin, a selective bradykinin B1 receptor agonist, causes only a weak contraction, suggesting the presence of badykinin B1 receptors in this tissue. In the present study, we attempted to characterise the receptor subtype and the possible mechanism by which des-Arg9-bradykinin induces contraction in this preparation. Contractions induced by des-Arg9-bradykinin in guinea-pig gallbladder (1 pM to 1 microM) increased significantly as a function of time elapsed after setting up of the preparation, reaching the maximum after 6 h of equilibration (EC50 16.4 pM and Emax 0.6 +/- 0.08 g). Des-Arg9-bradykinin-induced contraction in guinea-pig gallbladder was totally prevented by cycloheximide (70 microM, an inhibitor of protein synthesis), indomethacin (3 microM), ibuprofen (30 microM), phenidone (30 microM) or Ca2+-free medium plus EGTA, and was partially antagonised by MK 571 ((3-(3-(2-(7-chloro-2-quinolinyl) ethenyl) phenyl ((3-dimethyl amino-3-oxo-propyl) thio) methyl) propanoic acid, 0.1 microM) or by nicardipine (1 microM), but was not affected by dazoxiben (30 microM), staurosporine (100 nM) or L 655,240 (240 (3-[1-(4-clorobenzil)-5-fluoro-3-metilhyindol-2il] 2,2-dimetilpropanoic acid, 1 microM). Unexpectedly, des-Arg9-bradykinin-induced contraction was unaffected by the selective bradykinin B1 receptor antagonists, des-Arg9-[Leu8]-bradykinin and des-Arg9-NPC 17761 (des-Arg0-D-Arg [Hip3, D-HipE (transtiofenil)7, Oic8]-des-Arg9-bradykinin). However, the selective bradykinin B2 receptor antagonists, HOE 140 (D-Arg0-[Hyp3, Thi5, D-Tic7, Oic8]-bradykinin) and NPC 17731 (D-Arg0 [Hyp3, DHypE (transpropyl)7, Oic8]-bradykinin), completely blocked des-Arg9-bradykinin-mediated contraction. Pre-treatment of the animals with Escherichia coli endotoxin (lipopolysaccharide, 30 microg/animal, i.v., 24 h) did not significantly change the response to des-Arg9-bradykinin induction. It is concluded that des-Arg9-bradykinin-induced contractions in guinea-pig gallbladder are mediated primarily by the release of proinflammatory eicosanoid(s) derived from the cyclo-oxygenase pathway. These effects are unrelated to thromboxane A2 and do not seem to be coupled to activation of a protein kinase C-dependent mechanism. Response to des-Arg9-bradykinin increases as a function of the equilibration period of the preparation by a mechanism dependent on protein synthesis and seems to be mediated by activation of bradykinin B2 (but not B1) receptors. Finally, in contrast to that observed for bradykinin, the contraction induced by des-Arg9-bradykinin in guinea-pig gallbladder is fully dependent on the influx of extracellular Ca2+, partially through L-type Ca2+ channels.

It was attempted to obtain the standard rate constant (k0)for the anodic oxidation of Phenidone (P) in pliysical developers using a spectroelectrochemical measurement in which P was oxidized to Phenidone radical (P•) on a reflective silver electrode and in which the absorbance change owing to the formation and disappearance of P• was monitored spectrophotometrically. The k0 obtained in a silver thiocyanate developer loas nearly equal to that in the absence of the silver complex (k0*) and remained almost constant with time after addition of P, while that obtained in the silver thiosulphate developer was much smaller than k0* and increased with time. These results suggested an inhibition of the charge transfer by the adsorption of thiosulphate at the silver surface and a displacement of the inhibiting thiosulphate by a species produced from the P oxidation, for which the inhibiting effect is smaller than that of thiosulphate.

Topical cyclosporin A (CsA) was compared with dexamethasone, indomethacin and phenidone in edema, increases in vascular permeability, eicosanoids and cell-influx induced by arachidonic acid (AA) and tetradecanoylphorbol acetate (TPA) in mouse ears. CsA ED(50) on AA-edema (7.7 micrograms/ear) was similar to dexamethasone and lower than indomethacin and phenidone. CsA ED(50) in TPA edema (21 micrograms/ear) was higher than dexamethasone and lower than indomethacin or phenidone. All drugs equally reduce the AA-induced increase in vascular permeability, but CsA and dexamethasone had more activity on TPA. AA-increase in vascular 6-keto-PGF1 alpha was reduced by dexamethasone, indomethacin and phenidone but not by CsA; only phenidone reduced LTB4. TPA-increase in 6-keto-PGF1 alpha was reduced by CsA and indomethacin while CsA, dexamethasone and phenidone decreased LTB4. CsA, indomethacin and phenidone, but not dexamethasone, suppressed AA-neutrophil influx. In TPA-ears all drugs produced similar reduction in neutrophil influx. CsA was shown to be a good topical anti-inflammatory drug.

Objectives Lipoxygenases (LOX) are the key enzymes involved in the biosynthesis of leukotrienes and reactive oxygen species, which are implicated in pathophysiology of inflammatory disorders. This study was conducted to evaluate the inhibitory effect of water-soluble antioxidant ascorbic acid and its lipophilic derivative, ascorbic acid 6-palmitate (Vcpal) on polymorphonuclear lymphocyte 5-LOX and soybean 15-LOX (sLOX) in vitro. Methods LOX activity was determined by measuring the end products, 5-hydroperoxy eicosatetraenoic acid (5-HETE) and lipid hydroperoxides, by spectrophotometric and high performance liquid chromatography methods. The substrate-dependent enzyme kinetics and docking studies were carried out to understand the nature of inhibition. Key findings Vcpal potently inhibited 5-LOX when compared with its inhibitory effect on sLOX (IC50; 2.5 and 10.3 μm respectively, P = 0.003). Further, Vcpal inhibited 5-LOX more strongly than the known synthetic drugs: phenidone and nordihydroguaiaretic acid (P = 0.0007). Enzyme kinetic studies demonstrated Vcpal as a non-competitive reversible inhibitor of 5-LOX. In-silico molecular docking revealed high MolDock and Rerank score for Vcpal than ascorbic acid, complementing in-vitro results. Conclusion Both in-vitro and docking studies demonstrated Vcpal but not ascorbic acid as a non-competitive inhibitor of 5-LOX- and sLOX-induced lipid peroxidation, suggesting a key role for lipophilic nature in bringing about inhibition.

The mechanism of the silver complex dependence of superadditivity in physical development was studied by physical development on an evaporated gold layer and current measurement using a comparable model cell to the development. The development rate of the thiocyanate developer including Phenidone/hydroquinone or Phenidone/ascorbic acid agreed with that calculated from the theoretical equation for the catalytic current, while the development rate of the thiosulphate developer was much smaller than the theoretical value. The current flowing through the external circuit of the cell is governed by the silver complex used in the anodic bath. It was concluded that thiocyanate has no influence upon the anodic process of Phenidone, while thiosulphate inhibits it.