Arachidonic Acid-induced Mouse Ear Research Articles

P-MD013. Importance of bioactive flavonoids “pectolinarin” in inflammation and pain: Validation through in-vivo, in-vitro and molecular study

Introduction . Inflammation is part of the non-specific immune response that occurs in reaction to any type of bodily injury which further generates chronic inflammatory diseases such as rheumatoid arthritis, peripheral nerve disorders, asthma, cardiovascular diseases, diabetes, cancer etc. Flavonoids represent a huge family of polyphenolic compounds and more referred as “nutraceuticals” because of their vide range of pharmacological activities in the mammalian cell. Pectolinarin is one of the main phytoconstituents of Cirsium japonicum which is an important herb of Korea, China and Japan. Methods . Pharmacological data have been collected and analyzed for analgesic and anti- inflammatory activity through various in-vivo and in-silico model. Moreover molecular study was also performed through scientific data analysis to know their interaction with various inflammatory markers to confirm their pharmacological activity. Present work also summarized the scientific data analysis of various molecular studies of pectolinarin with inflammatory receptor targets such as COX-2, TNFα, IL-1β and IL-6. Results . Scientific data analysis showed that pectolinarin reduces tissue damage and alleviates the oxidative and inflammatory events through direct influence on COX-2, TNFα, IL-1β and IL-6. Molecular study against inflammatory receptor targets showed their effectiveness in the inflammatory disorders. Further data analysis also suggested that pectolinarin significantly inhibited cell viability in rheumatoid arthritis and have inhibitory activities against carrageenan-induced mouse paw edema and arachidonic acid-induced mouse ear edema in some other study. However pectolinarin also exert significant analgesic and anti-inflammatory activities in mice and rats which also support the molecular study. Owing to the importance of pectolinarin in the medicine, a better understanding of their biological activities indicates their potentials as anti-inflammatory agents. Conclusion . Present study data analysis indicated and proven the anti-inflammatory potential of pectolinarin which can be exploited for commercial designing of novel anti-inflammatory drug in the future to treat various inflammatory disorders.

Anti‐inflammatory, Anti‐proliferative Activities from the Skin of the Catfish Arius Bilineatus, Valenciennes

The catfish secretes a gelatinous substance composed of biochemically active lipids and proteins from its skin upon stress or injury. Preparations from the skin have previously been shown to affect blood clotting and accelerates healing of non‐healing diabetic foot ulcers in man. Here catfish skin preparation (CSP) and its lipid fraction were investigated with the focus on its ability to alter key inflammatory mediators and to inhibit the proliferation of human non‐small cell lung cancer (NSCLC) A549 cells and human hepatocellular carcinoma Hep3B cells. The anti‐inflammatory activity was determined by its effect on arachidonate metabolism in cells in vitro or in mouse ear tissues by LC/MS/MS method, and on the inflammatory genes analyzed by inflammation array kits (PCR based). The antiproliferative activity of CSP was evaluated by MTT assay. When A549 cells were treated with CSP or different lipid fraction of CSP (200 μg/ml), total lipid fraction noticeably reduced the cellular level of PGE2 by 64.2%, whereas the petroleum either fraction of CSP decreased the production of PGI2, TEXB2, PGF2α, PGE2 and PGE1 by 42%, 24%, 76%, 55% and 68%, respectively compared to that of control vehicle treated cells. Similarly, chloroform fraction of CSP also reduced the cellular level of PGI2 and PGF2α by 67% and 74%, respectively in A549 cells. To further identify the anti‐inflammatory properties of CSP, we then tested the anti‐inflammatory effect of CSP in arachidonic acid induced mouse ear model. Intriguingly, the cream prepared from the total lipid CSP (10 mg) reduced the redness of ears caused by arachidonic acid, and significantly reduced mouse ear weight (p < 0.05) suggesting anti‐inflammatory activity of the CSP. Analyzing mouse ear eicosanoid levels revealed that PGE2 was reduced by 28% as well as 5‐lipoxygenase metabolite 5‐HETE by 30% in the CSP cream treated group compared to that of control group. The inflammatory genes were further tested in the control and CSP cream treated mouse ear tissues. Intriguingly, the LTA4 hydrolase gene which is downstream of 5‐LOX and responsible for formation of pro‐inflammatory mediator LTB4 was reduced by 50%. Given inflammation is one of the key factors associated with tumor development, we then tested the anti‐proliferative activities of the total lipid extract and its lipid fractions in A549 cells and Hep3B cells. The growth of both A549 and Hep3B cells was significantly inhibited by chloroform fraction of CSP with IC50 around 25 mg/ml. Together, these data suggest that CSP and its lipid soluble fraction have both anti‐inflammatory and anti‐proliferative activities which may be mediated through alteration of arachidonate metabolism and warrants further investigation.Support or Funding InformationThis study was support by a grant from Kuwait Foundation for the Advancement of Science No. KFAS 201320701A‐D, and Kuwait University Research Grant No. SL03/14.

Inhibitory effect of glycyrrhetinic acid derivatives on arachidonic acid-induced mouse ear oedema.

The inhibitory effects of glycyrrhetinic acid and its derivatives were examined on arachidonic acid (AA)-induced ear oedema in mice. Of the compounds, dihemiphthalate derivatives of 18 beta-olean-12-ene-3 beta, 30-diol (IId, IId'), 18 beta-olean-9(11)12-diene-3 beta, 30-diol (IIIa, IIIa') and olean-11, 13(18)-diene-3 beta, 30-diol (IVa, IVa') showed a strong inhibition of ear oedema on both tropical (ID50, 1.9, 2.8 and 1.7 mg/ear, respectively) and oral (ID50, 90, 130 and 88 mg kg-1, respectively) administration. Topical ID50 values were approximately the same potency as nordihydroguaiaretic acid (ID50, 2.1 mg/ear). Given topically these compounds were also capable of inhibiting PGE2 and LTC4 formation at an early stage of AA-induced ear oedema. However, glycyrrhetinic acid (Ia) and deoxoglycyrrhetol (IIa), the fundamental skeletons of the derivatives, showed no detectable inhibition of oedema at a dose of 1 mg/ear (topical) or 200 mg kg-1 (oral). The most effective time for the topical administration of the compound IId against ear oedema was 0-30 min before AA application; this is different from dexamethasone which requires a time lag for reaction. The results suggest that the inhibitory effect of the hemiphthalate compounds (IId, IId', IIIa, IIIa', IVa and IVa') is a direct action, and does not involve the anti-inflammatory action of steroids mediated by the secondary formation of a reactive protein.

Inhibitory effects of 1,3-bis-(2-substituted-phenyl)-propane-1,3-dione, β-diketone structural analogues of curcumin, on chemical-induced tumor promotion and inflammation in mouse skin

Dibenzoylmethane (DBM), a β-diketone structural analogue of curcumin, has been reported to exhibit anti-tumorigenic and chemopreventive activities. Due to the structural resemblance of DBM to the anti-inflammatory curcumin and an aspirin-like skeleton of DBM derivatives, we tested the anti-inflammatory effects of DBM and its derivatives, 1,3-bis-(2-substituted-phenyl)-propane-1,3-dione, on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced tumor promotion as well as TPA- and arachidonic acid-induced mouse ear edema in skin of CD-1 mice. Topical application of 10 μmol DBM together with TPA on the back of mice previously treated with 7,12-dimethylbenz[α]anthracene (DMBA) inhibited TPA-induced skin tumor promotion significantly. In addition, 1,3-bis-(2-acetoxy phenyl)-propane-1,3-dione was a superior anti-inflammatory agent to aspirin (80% of inhibition), on TPA-induced mouse ear edema and reduced the production of prostaglandin E2 (PGE(2)), comparable to aspirin. Taken together, 1,3-bis-(2-acetoxyphenyl-propane-1,3-dione merits a valuable anti-inflammatory agent substituting aspirin in therapeutic treatment as well prevention of cancer.

In vitro and in vivo anti-inflammatory effects of pegmatite

Pegmatite is a coarse-grained intrusive igneous rock rich in rare elements such as uranium, tungsten, and tantalum with Ca, K, Mg, Fe, Se, Ge, and Ho. We tested in vitro and in vivo assays for the anti-inflammatory activity of pegmatites. We firstly evaluated the suppressive effects of pegmatite on macrophage cell line RAW 264.7 cells stimulated with proinflammatory stimuli lipopolysaccharide (LPS) to determine nitric oxide (NO) production and TNF-α and IL-6 release. The IC50 values of pegmatite exceeded 5,000 μg/mL. Treatment of RAW 264.7 cells with pegmatite significantly inhibited LPS-stimulated NO production and proinflammatory cytokines such as TNF-α and IL-6 secretion in a dose-dependent manner (P<0.05). In vivo studies were tested with two animal models of arachidonic acid-induced mouse ear edema and an acetic acid-induced increase in capillary permeability. The pegmatite significantly attenuated ear edema induced by arachidonic acid and reduced the acetic acid-induced increase in capillary permeability in mice (P<0.05) when the pegmatite was administered topically (10 mg per ear) for 24 h. Therefore, pegmatite potentially shows an anti-inflammatory activity in the in vitro and in vivo mice and in the development of newer anti-inflammatory agents as mineral materials.

Anti-Inflammatory Activity of the Total Flavonoid Fraction from Broussonetia papyrifera in Combination with Lonicera japonica

【To establish the anti-inflammatory activity of the total flavonoid fraction of the root barks of Broussonetia papyrifera (EBP) and a new formula, the ethanol extract of the root barks of B. papyrifera was fractionated with ethylacetate, yielding the hydrophobic prenylated flavonoid-enriched fraction. EBP and the ethanol extract of the whole Lonicera japonica (ELJ) plant were then mixed at a ratio of 1:1 (w/w) to give a new preparation (BL) in the hope of obtaining an optimal formula with a higher anti-inflammatory activity. Evaluation of the effects of these preparations on A23187-treated rat basophilic leukemia (RBL-1) cells revealed that EBP potently inhibited 5-lipoxygenase (5-LOX), while ELJ showed weak inhibition. Additionally, the mixture (BL) clearly showed stronger inhibitory effects against 5-LOX than either preparation alone. These preparations also inhibited cyclooxygenase-2-catalyzed $PGE_2$ and inducible nitric oxide (NO) synthase-catalyzed NO production by lipopolysaccharide-treated RAW 264.7 cells. When tested against arachidonic acid-induced mouse ear edema, EBP showed strong inhibitory activity at doses of 5-200 mg/kg when administered orally, but BL had obviously stronger inhibitory effects. When tested against ${\lambda}$ -carrageenan-induced paw edema in mice, BL showed a potent and synergistic anti-inflammatory effect. In addition, in the acetic acid-induced writhing test, BL was found to have strong analgesic activity at 50-400 mg/kg. Taken together, these results indicate that each of these preparations exert anti-inflammatory activity in vitro and in vivo. In particular, BL showed stronger anti-inflammatory activity than EBP, and these anti-inflammatory effects were partially related to the inhibition of eicosanoid and NO production. BL may be useful for the treatment of human inflammatory disorders.】

Anti-inflammatory effects of locally applied enzyme-loaded ultradeformable vesicles on an acute cutaneous model

Superoxide dismutase (SOD) and catalase (CAT) are active scavengers of reactive oxygen species and were incorporated into ultradeformable vesicles with the aim of increasing enzyme bioavailability (skin delivery). These special very adaptable vesicles have been formulated and optimized for enzyme transport in order to penetrate into or across the intact skin barrier. Anti-inflammatory activity of SOD-loaded, CAT-loaded and of SOD- and CAT-loaded ultradeformable vesicles applied epicutaneously was measured using different protein doses on the skin, on an arachidonic acid-induced mouse ear oedema. The biological anti-oedema activity is a measurement of drug-targeting potentiation in the organ. Delivery by means of deformable vesicles was compared to conventional vesicles or the absence of an enzyme carrier mediated transport. This was done at various times following prophylactic application of the test formulations. Positive reference groups were treated epicutaneously with several low molecular weight non-steroidal anti-inflammatory drugs (NSAIDs). The latter included indomethacin (3 mg kg−1), etofenamate (30 mg kg−1) and piroxicam (1 mg kg−1) and reduced the oedema by 94 ± 4%, 81 ± 4% and 42 ± 5%, respectively, if measured 30 min after ear treatment with a NSAID. Of the enzyme-loaded carriers tested, only the enzyme-loaded ultradeformable vesicles reduced the swelling of ears significantly: SOD (90 µg kg−1), CAT (250 µg kg−1) and SOD (90 µg kg−1) plus CAT (250 µg kg−1) reduced the oedema by 70 ± 12%, 65 ± 10% and 61 ± 19%, respectively, at t = 30 min. Aqueous enzyme solutions and empty carriers had no such effect. The combination of two enzymes resulted in no increased therapeutic effect, but the results are inconclusive since only two dose combinations were tested. The results presented in this study suggest that antioxidant enzymes delivered by means of ultradeformable lipid vesicles can serve as a novel region-specific treatment of inflammation.

Anti-Inflammatory Activity of the Ethanol Extract of Chungkukjang, Korean Fermented Bean: 5-Lipoxygenase Inhibition

The anti-inflammatory activity of Chungkukjang, a Korean traditional fermented soybean food (Korean-style Natto), was examined for the first time. From the results, it was found that the ethanol extract of Chungkukjang inhibited 5-lipoxygenase from A23187-treated RBL-1 cells, reducing leukoriene production (50% inhibitory concentration = 54.1 microg/mL). However, it did not greatly affect cyclooxygenase-2-catalyzed prostaglandin E(2) and inducible nitric oxide synthase-catalyzed nitric oxide production from lipopolysaccharide-treated RAW 264.7 cells at the same concentration ranges. Since leukotrienes are intimately involved in some allergic disorders, the anti-allergic activity of Chungkukjang was further examined in animal models of passive cutaneous anaphylaxis (type I hypersensitivity) and arachidonic acid-induced ear edema, two well-known in vivo models sensitive to 5-lipoxygenase inhibitors. After oral administration for 5 consecutive days, Chungkukjang significantly reduced (27.3%) passive cutaneous anaphylaxis in rats at 400 mg/kg/day. It also showed in vivo anti-inflammatory activity against arachidonic acid-induced mouse ear edema. Therefore, it is suggested that Chungkukjang may be beneficial for several allergic conditions such as asthma and atopic dermatitis.

Anti-inflammatory Activity of Pectolinarigenin and Pectolinarin Isolated from Cirsium chanroenicum

In order to identify the active anti-inflammatory ingredient(s) in Cirsium chanroenicum (Compositae), its methanol extract and several solvent fractions were prepared; the methanol extract and the ethylacetate fraction inhibited cyclooxygenase-2 (COX-2)-mediated prostaglandin E2 (PGE2) and 5-lipoxygenase (5-LOX)-mediated leukotriene (LT) production in lipopolysaccharide-treated RAW 264.7 cells and A23187-treated rat basophilic leukemia (RBL-1) cells, respectively. Further bioactivity-guided fractionation of the ethylacetate fraction using column chromatography led to the isolation of pectolinarigenin (5,7-dihydroxy-4',6-dimethoxyflavone), along with pectolinarin [pectolinarigenin 7-rhamnosyl-(1-->6)-glucoside]. Pectolinarigenin strongly inhibited COX-2-mediated PGE2 and 5-LOX-mediated LT production at >1 microM, indicating that it is a dual inhibitor of COX-2/5-LOX. However, pectolinarigenin did not affect COX-2 expression or nuclear transcription factor (NF-kappaB) activation. In addition, in vivo studies demonstrated that oral administration of these two compounds at 20-100 mg/kg resulted in similar inhibitory activities against several animal models of inflammation/allergy: arachidonic acid-induced mouse ear edema, carrageenan-induced mouse paw edema and passive cutaneous anaphylaxis. All of these results suggest that pectolinarigenin and pectolinarin possess anti-inflammatory activity and that they may inhibit eicosanoid formation in inflammatory lesions. These activities certainly contribute to the anti-inflammatory mechanism of C. chanroenicum.

A Medicinal Extract ofScutellaria baicalensisandAcacia catechuActs as a Dual Inhibitor of Cyclooxygenase and 5-Lipoxygenase to Reduce Inflammation

A mixed extract containing two naturally occurring flavonoids, baicalin from Scutellaria baicalensis and catechin from Acacia catechu, was tested for cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) inhibition via enzyme, cellular, and in vivo models. The 50% inhibitory concentration for inhibition of both ovine COX-1 and COX-2 peroxidase enzyme activities was 15 microg/mL, while the mixed extract showed a value for potato 5-LOX enzyme activity of 25 microg/mL. Prostaglandin E2 generation was inhibited by the mixed extract in human osteosarcoma cells expressing COX-2, while leukotriene production was inhibited in both human cell lines, immortalized THP-1 monocyte and HT-29 colorectal adenocarcinoma. In an arachidonic acid-induced mouse ear swelling model, the extract decreased edema in a dose-dependent manner. When arachidonic acid was injected directly into the intra-articular space of mouse ankle joints, the mixed extract abated the swelling and restored function in a rotary drum walking model. These results suggest that this natural, flavonoid mixture acts via "dual inhibition" of COX and LOX enzymes to reduce production of pro-inflammatory eicosanoids and attenuate edema in an in vivo model of inflammation.

In vitro and in vivo pharmacological characterization of SB 201993, an eicosanoid-like LTB 4receptor antagonist with anti-inflammatory activity

Summary Leukotriene B 4(LTB 4) and 12-(R)-hydroxy-5,8,10,14-eicosatetraenoic acid (12-[R]-HETE) have been postulated to contribute to the pathophysiology of inflammatory diseases. SB 201993, (E)-3 [[[[6-(2-carboxyethenyl)-5-[lsqb;8-(4-methoxyphenyl)octyl] oxy]-2-pyridinyl] methyl] thio] methyl] benzoic acid, identified from a chemical series designed as ring-fused analogs of LTB 4, was evaluated as an antagonist of LTB 4- and 12-(R)-HETE-induced responses in vitro and for anti-inflammatory activity in vivo. SB 201993 competitively antagonized ‘ 3-H’-LTB 4binding to intact human neutrophils (K i= 7.6 NM) and to membranes of RBL 2H3 cells expressing the LTB 4receptor (RBL 2H3-LTB 4R; IC 50= 154 nM). This compound demonstrated competitive antagonism of LTB 4- and 12-(R)-HETE-induced Ca 2+mobilization responses in human neutrophils (IC 50s of 131 nM and 105 nM, respectively) and inhibited LTB 4-induced Ca 2+mobilization in human cultured keratinocytes (IC 50= 61 nM), RBL 2H3-LTB 4R cells (IC 50= 255 nM) and mouse neutrophils (IC 50= 410 nM). SB 201993 showed weak LTD 4-receptor binding affinity (K i= 1.9 μM) and inhibited 5-lipoxygenase (IC 50of 3.6 mM), both in vitro and ex vivo. In vivo, SB 201993 inhibited LTB 4-induced neutrophil infiltration in mouse skin and produced dose-related, long lasting topical anti-inflammatory activity against the fluid and cellular phases of arachidonic acid-induced mouse ear inflammation (ED 50of 580 μg/ear and 390 μg/ear, respectively). Similarly, anti-inflammatory activity was also observed in the murine phorbol ester-induced cutaneous inflammation model (ED 50of 770 and 730 mg/ear, respectively, against the fluid and cellular phases). These results indicate that SB 201993 blocks the actions of LTB 4and 12-(R)-HETE and inhibits a variety of inflammatory responses; and thus may be a useful compound to evaluate the role of these mediators in disease models.

Favorable combination effects of the leukotriene synthesis inhibitor BAY X 1005 and dexamethasone on edema formation in the arachidonic acid-induced mouse ear inflammation test

The effects of a combination of the leukotriene synthesis inhibitor (LSI) BAY X 1005 with the glucocorticosteroid dexamethasone were studied in the arachidonic acid (AA)-induced mouse ear inflammation test (AA-MEIT). We have determined the dose-dependent effects of dexamethasone to reduce edema formation when a combination of 25 mg/kg BAY X 1005 and increasing dosages of dexamethasone was administered orally (p.o.). The inhibition of ear thicknesses increases with the combination therapy were compared with the inhibition observed when both compounds were applied alone.The edema inhibition at the fixed oral dose of 25 mg/kg p.o. BAY X 1005 was 57±2%. Dexamethasone alone dose-dependently inhibited edema formation with a flat inhibition curve at dosages ranging from 0.008 mg/kg (11±13%) to 0.5 mg/kg (65±11%). In combination with BAY X 1005, the corresponding inhibition curve for dexamethasone was shifted upward starting from 56±13% at 0.008 mg/kg. At the two highest dexamethasone dosages (0.125 mg/kg and 0.5 mg/kg) an identical inhibition (86±10%) was observed indicating a plateauing of the antiedematous effect of this combination. The results indicate that at suitable dosages (0.031 mg/kg and 0.125 mg/kg) the effects of BAY X 1005 and dexamethasone were additive.To further corroborate the combination effects of BAY X 1005 and dexamethasone the 5-HT receptor antagonist methysergide and the H1 receptor antagonist pyrilamine were employed as a pretreatment to eliminate mouse-specific inflammation responses. In the methysergide/pyrilamine (12.5 mg/kg s.c. each)-conditioned AA-MEIT model 85±3% edema reduction were observed with BAY X 1005 and 74±3% with dexamethasone. The combination of 25 mg/kg BAY X 1005 and 0.5 mg/kg dexamethasone was slightly more effective in the conditioned AA-MEIT (90±3%) than either compound alone.Our results demonstrate that the LSI BAY X 1005 interacted favorably with the glucocorticosteroid dexamethasone suggesting a potentially useful new combination strategy to treat acute inflammatory disease conditions. This effect can be explained on the basis of the mechanisms of action of both therapeutic principles.

Carboxy-substituted cinnamides: a novel series of potent, orally active LTB4 receptor antagonists.

A series of carboxy-substituted cinnamides were investigated as antagonists of the human cell surface leukotriene B4 (LTB4) receptor. Binding was determined through measurement of [3H]LTB4 displacement from human neutrophils. Receptor antagonism was confirmed through a functional assay, which measures inhibition of Ca2+ release in human neutrophils. Potent antagonists were discovered through optimization of a random screening hit, a p-(alpha-methylbenzyloxy)cinnamide, having low-micromolar activity. Substantial improvement of in vitro potency was realized by the attachment of a carboxylic acid moiety to the cinnamide phenyl ring through a flexible tether, leading to identification of compounds with low-nanomolar potency. Modification of the benzyloxy substituent, either through ortho-substitution on the benzyloxy phenyl group or through replacement of the ether oxygen with a methylene or sulfur atom, produced achiral antagonists of equal or greater potency. The most potent compounds in vitro were assayed for oral activity using the arachidonic acid-induced mouse ear edema model of inflammation. Several compounds in this series were found to significantly inhibit edema formation and myeloperoxidase activity in this model up to 17 h after oral administration. Representatives of this series have been shown to be potent and long-acting orally active inhibitors of the LTB4 receptor.

(+/-)-trans-2-[3-methoxy-4-(4-chlorophenylthioethoxy)-5-(N-methyl-N- hydroxyureidyl)methylphenyl]-5-(3,4, 5-trimethoxyphenyl)tetrahydrofuran (CMI-392), a potent dual 5-lipoxygenase inhibitor and platelet-activating factor receptor antagonist.

By incorporating an N-hydroxyurea functionality onto diaryltetrahydrofurans, a novel series of compounds was investigated as dual 5-lipoxygenese (5-LO) inhibitor and platelet-activating factor (PAF) receptor antagonist. These dual functional compounds were evaluated in vitro for 5-LO inhibition in RBL cell extracts and human whole blood, and PAF receptor antagonism in a receptor binding assay. PAF-induced hemoconcentration and arachidonic acid- and TPA-induced ear edema in mice were used to determine in vivo activities. The structure-activity relationship analysis to define a preclinical lead is presented. (+/-)-trans-2-[3-methoxy-4-(4-chlorophenylthioethoxy)-5-(N-methyl- N-h ydroxyureidyl)methylphenyl]-5-(3,4, 5-trimethoxyphenyl)tetrahydrofuran (40, CMI-392) was selected for further study. In the arachidonic acid-induced mouse ear edema model, 40 was more potent than either zileuton (a 5-LO inhibitor) or BN 50739 (a PAF receptor antagonist), and it demonstrated the same inhibitory effect as a physical combination of the latter two agents. These results suggest that a single compound which both inhibits leukotriene synthesis and blocks PAF receptor binding may provide therapeutic advantages over single-acting agents. The clinical development of compound 40 is in progress.

1,5-Disubstituted indazol-3-ols with anti-inflammatory activity.

A series of new indazol-3-ol derivatives was synthesized. Some of these compounds exhibit interesting anti-inflammatory activities in various models of inflammation. 5-Methoxy-1-[quinoline-2-yl-methoxy)-benzyl]-1H-indazol-3-ol (27) strongly inhibits the oxidation of arachidonic acid to 5-hydroperoxyeicosatetraenoic acid catalyzed by 5-lipoxygenase (IC50 = 44 nM). 27 also inhibits the contraction of sensitized guinea pig tracheal segments (IC50 = 2.9 microM). In guinea pigs treated with 27 (1 mg/kg i.p.) 2 h before antigen provocation, there was a marked inhibition (47%) of the antigen-induced airway eosinophilia. After topical application of 1 microgram/ear 27 inhibits the arachidonic acid induced mouse ear edema (41%).

Effects of indole-3-acetic acid on croton oil- and arachidonic acid-induced mouse ear edema.

The indole-3-acetic acid (IAA) is a plant growth hormone (auxin) being considered as a tryptophan metabolite in animals. The main purpose of this work was to verify IAA's topical anti-inflammatory action using croton oil- or arachidonic acid-induced mouse ear edema, in comparison to known anti-inflammatory agents. IAA antioxidant activity was also verified by measuring the inhibition of brain homogenate lipid peroxidation with the thiobarbituric acid reactive substances (TBARS) test. IAA inhibited the action of both croton oil-and arachidonic acid-induced edema in a dose-dependent manner (4.0 mumoles IAA inhibited 75.8% in croton oil and 82.5% in arachidonic acid induced ear edema). Both IAA (5.3 mM) and indomethacin (8.0 mM) inhibited TBARS formation. Data suggest that IAA exhibits antiinflammatory effect possibly by its anti-oxidant activity.

Anti-inflammatory activity of croconazole, a broad-spectrum antimycotic agent, in the arachidonic acid-induced mouse ear swelling test.

Investigations on croconazole, a novel imidazole compound, suggested antiphlogistic properties in vitro. Hence, its anti-inflammatory capacity was tested in vivo using the arachidonic acid-induced mouse ear swelling test, which is a suitable model for screening inhibitors of the lipoxygenase and/or the cyclooxygenase. Topical application of croconazole (1%/0.01%) to the mouse ear induced a maximal inhibition of edema (inhibition: 39%/33%; p = 0.01) which was as strong as the reference nordihydroguaiaretic acid (inhibition: 38.9%; p = 0.01). These results justify further investigations on croconazole to study potential inhibitory effects on proinflammatory arachidonic acid metabolites.

Antiinflammatory activity of flavonoids: Mouse ear edema inhibition

In this investigation, the various flavonoid aglycones were evaluated for their inhibitory activities against croton-oil or arachidonic acid induced mouse ear edema by oral or topical administration. The compounds tested were thirteen derivatives of flavan-3-ol (catechin and epicatechin), flavanone (flavanone and naringenin), flavone (flavone, chrysin and apigenin), flavonol (flavonol, galangin, quercetin and morin) and isoflavone (biochanin A and 2-carbethoxy5,7-dihydroxy-4′-methoxyisoflavone), along with hydrocortisone, indomethacin, 4-bromophenacyl bromide, nordihydroguaiaretic acid and phenidone as positive controls. As a general, 5,7-dihydroxy-flavonols having hydroxyl group(s) in B-ring and biochanin A (isoflavone) were found to show broad inhibitory activities (14–52%) against croton-oil or arachidonic acid induced ear edema by oral or topical application at the dose of 2 mg/mouse, although they showed less activity than hydrocortisone (26–88%) or indomethacin (36–80%). Flavonoid aglycones tested showed higher activity when applied topically than by the oral administration. It was also found that they inhibited arachidonic acid induced edema more profoundly than croton-oil induced edema by topical application. In arachidonic acid induced edema when applied topically, flavone derivatives such as flavone, chrysin and apigenin were revealed to be the good inhibitory agents in addition to flavonols and isoflavones. When quercetin and biochanin A were selected for evaluating in carrageenan induced rat pleurisy model (5 hr and 24 hr), both flavonoids showed antiinflammatory activity at the dose of 70 mg/kg by the oral administration. All of these results revealed that flavonoid aglycones, especially 5,7-dihydroxy-flavonols having hydroxyl group(s) in B-ring and biochanin A (isoflavone) possessedin vivo antiinflammatory activity.

P-271 - Effect of antiinflammatory agents on arachidonic acid-induced mouse ear edema

P-271 - Effect of antiinflammatory agents on arachidonic acid-induced mouse ear edema

Topical nonsteroidal antipsoriatic agents. 2. 2,3-(Alkylidenedioxy)naphthalene analogues of lonapalene.

A series of 2,3-(alkylidenedioxy)naphthalene (5a-p) analogues of lonapalene (RS-43179, 1), a 5-lipoxygenase inhibitor currently under clinical investigation for the treatment of psoriasis, has been prepared and evaluated for topical inhibitory activity against arachidonic acid induced mouse ear edema. The results of these studies demonstrate that introduction of the fused 2,3-alkylidenedioxy ring, in place of the acyclic 2,3-dialkoxy substituent pattern characteristic of the previous series, caused a modest dimunition in overall potency within the series. These results suggest a potential steric intolerance for these extended planar analogues, in comparison with their 2,3-dialkoxy predecessors.