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  1. Ng CH, Rullah K, Aluwi MF, Abas F, Lam KW, Ismail IS, et al.
    Molecules, 2014;19(8):11645-59.
    PMID: 25100256 DOI: 10.3390/molecules190811645
    The natural product molecule 2,4,6-trihydroxy-3-geranyl-acetophenone (tHGA) isolated from the medicinal plant Melicope ptelefolia was shown to exhibit potent lipoxygenase (LOX) inhibitory activity. It is known that LOX plays an important role in inflammatory response as it catalyzes the oxidation of unsaturated fatty acids, such as linoleic acid to form hydroperoxides. The search for selective LOX inhibitors may provide new therapeutic approach for inflammatory diseases. Herein, we report the synthesis of tHGA analogs using simple Friedel-Craft acylation and alkylation reactions with the aim of obtaining a better insight into the structure-activity relationships of the compounds. All the synthesized analogs showed potent soybean 15-LOX inhibitory activity in a dose-dependent manner (IC50 = 10.31-27.61 μM) where compound 3e was two-fold more active than tHGA. Molecular docking was then applied to reveal the important binding interactions of compound 3e in soybean 15-LOX binding site. The findings suggest that the presence of longer acyl bearing aliphatic chain (5Cs) and aromatic groups could significantly affect the enzymatic activity.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  2. Ahmed S, Gul S, Idris F, Hussain A, Zia-Ul-Haq M, Jaafar HZ, et al.
    Molecules, 2014;19(8):11385-94.
    PMID: 25090125 DOI: 10.3390/molecules190811385
    Human plasma inhibits arachidonic acid metabolism and platelet aggregation. This helps human form a haemostatic control system that prevents the progress of certain aggregatory or inflammatory reactions. Whether this property of plasma is unique to human or extends to other species is not well known. It is speculated that this protective ability of plasma remains evolutionarily conserved in different mammals. In order to confirm this, the effect of plasma from 12 different mammalian species was investigated for its inhibitory potential against arachidonic acid metabolism and platelet aggregation. Metabolism of arachidonic acid by cyclooxygenase and lipoxygenase pathways was studies using radio-immuno assay and thin layer chromatography while platelet aggregation in the plasma of various mammals was monitored following turbedmetric method in a dual channel aggregometer. Results indicate that inhibition of AA metabolism and platelet aggregation is a common feature of plasma obtained from different mammalian species, although there exists large interspecies variation. This shows that besides human, other mammals also possess general protective mechanisms against various aggregatory and inflammatory conditions and this anti-inflammatory property of the plasma is evolutionarily conserved in mammalian species. The most likely candidates responsible for these properties of plasma include haptoglobin, albumin and lipoproteins.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  3. Chan KY, Mohamad K, Ooi AJ, Imiyabir Z, Chung LY
    Fitoterapia, 2012 Jul;83(5):961-7.
    PMID: 22565147 DOI: 10.1016/j.fitote.2012.04.018
    Lipoxygenase (LOX)-inhibiting compounds from the leaves of Chisocheton polyandrus Merr. were isolated in this study using a bioactivity-guided fractionation technique. Two dammarane triterpenoids, dammara-20,24-dien-3-one (1) (IC(50)=0.69±0.07 μM) and 24-hydroxydammara-20,25-dien-3-one (2) (IC(50)=1.11±0.38 μM), were isolated and identified based on the soybean LOX assay. Dammara-20,24-dien-3-one (1) exhibited dual inhibition of both human 5-LOX (IC(50)=24.27±2.92 μM) and cyclooxygenase-2 (COX-2) (IC(50)=3.17±0.90 μM), whereas 24-hydroxydammara-20,25-dien-3-one (2) did not exhibit any significant inhibitory effects. This report is the first to detail the inhibition of LOX and COX by both C. polyandrus and its isolated compounds.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology*
  4. Shaha MKK, Sirata HM, Jamil S, Jalil J
    Nat Prod Commun, 2016 Sep;11(9):1275-1278.
    PMID: 30807020
    A new pyranoflavone, methoxycyclocommunol (1) together with four known flavonoids, artonin F (2), heteroflavanone A (3), cudraflavone C (4) and cyclocommunol (5) were isolated from the bark of Artocarpus integer var. silvestris Corner. Their structures were elucidated through extensive spectroscopic- techniques (UV, IR, MS, 1D-NMR and 2D-NMR) and by comparison with literature data. All the pure compounds were tested for their anti-inflammatory activities by using screening kit and radioimmunoassay methods. In a 15-lipoxygenase (15-LOX) inhibitory assay, compounds 1, 2, 4 and 5 gave weak percentages of inhibition, 16.5, 18.3, 17.6, 10.2%, respectively at the concentration of 100 μM. Compounds 1, 3 and 4, however, showed strong dose- dependent inhibition towards prostaglandin E₂ (PGE₂) production in lipopolysaccharide-induced human whole blood using a radioimmunoassay method with IC₅₀ values of 4.3, 0.8, and 0.07 μM, respectively suggesting that they strongly exhibited cyclooxygenase-2 (COX-2) activity.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  5. Agbo EN, Gildenhuys S, Choong YS, Mphahlele MJ, More GK
    Bioorg Chem, 2020 08;101:103997.
    PMID: 32554280 DOI: 10.1016/j.bioorg.2020.103997
    A series of furocoumarin-stilbene hybrids has been synthesized and evaluated in vitro for inhibitory effect against acetylcholinesterase (AChE), butyrylcholinestarase (BChE), β-secretase, cyclooxygenase-2 (COX-2), and lipoxygenase-5 (LOX-5) activities including free radical-scavenging properties. Among these hybrids, 8-(3,5-dimethoxyphenyl)-4-(3,5-dimethoxystyryl)furochromen-2-one 4h exhibited significant anticholinesterase activity and inhibitory effect against β-secretase, COX-2 and LOX-5 activities. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and an in vitro cell-based antioxidant activity assay involving lipopolysaccharide induced reactive oxygen species production revealed that 4h has capability of scavenging free radicals. Molecular docking into AChE, BChE, β-secretase, COX-2 and LOX-5 active sites has also been performed.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  6. Rehman A, Abbasi MA, Siddiqui SZ, Mohyuddin A, Nadeem S, Shah SA
    Pak J Pharm Sci, 2016 Sep;29(5):1489-1496.
    PMID: 27731801
    New potent organic compounds were synthesized with an aim of good biological activities such as antibacterial and anti-enzymatic. Three series of sulfonamide derivatives were synthesized by treating N-alkyl/aryl substituted amines (2a-f) with 4-chlorobenzensulfonyl chloride (1) to yield N-alkyl/aryl-4-chlorobenzenesulfonamide(3af) that was then derivatized by gearing up with ethyl iodide (4), benzyl chloride (5) and 4-chlorobenzyl chloride (6) using sodium hydride as base to initialize the reaction in a polar aprotic solvent (DMF) to synthesize the derivatives, 7a-f, 8af and 9a-f respectively. Structure elucidation was brought about by IR, 1H-NMR and EIMS spectra for all the synthesized molecules which were evaluated for their antibacterial activities and inhibitory potentials for certain enzymes.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  7. Abbasi MA, Anwar A, Rehman A, Siddiqui SZ, Rubab K, Shah SAA, et al.
    Pak J Pharm Sci, 2017 Sep;30(5):1715-1724.
    PMID: 29084694
    Heterocyclic molecules have been frequently investigated to possess various biological activities during the last few decades. The present work elaborates the synthesis and enzymatic inhibition potentials of a series of sulfonamides. A series of 1-arylsulfonyl-4-Phenylpiperazine (3a-n) geared up by the reaction of 1-phenylpiperazine (1) and different (un)substituted alkyl/arylsulfonyl chlorides (2a-n), under defined pH control using water as a reaction medium. The synthesized molecules were characterized by 1H-NMR, 13C-NMR, IR and EI-MS spectral data. The enzyme inhibition study was carried on α-glucosidase, lipoxygenase (LOX), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) enzymes supported by docking simulation studies and the IC50 values rendered a few of the synthesized molecules as moderate inhibitors of these enzymes where, the compound 3e exhibited comparatively better potency against α-glucosidase enzyme. The synthesized compounds showed weak or no inhibition against LOX, AChE and BChE enzymes.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  8. Bukhari SN, Lauro G, Jantan I, Bifulco G, Amjad MW
    Bioorg Med Chem, 2014 Aug 1;22(15):4151-61.
    PMID: 24938495 DOI: 10.1016/j.bmc.2014.05.052
    Arachidonic acid and its metabolites have generated high level of interest among researchers due to their vital role in inflammation. The inhibition of enzymes involved in arachidonic acid metabolism has been considered as synergistic anti-inflammatory effect. A series of novel α,β-unsaturated carbonyl based compounds were synthesized and evaluated for their inhibitory activity on secretory phospholipase A₂ (sPLA₂), cyclooxygenases (COX), soybean lipoxygenase (LOX) in addition to proinflammatory cytokines comprising IL-6 and TNF-α. Six α,β-unsaturated carbonyl based compounds (2, 3, 4, 12, 13 and 14) exhibited strong inhibition of sPLA₂ activity, with IC₅₀ values in the range of 2.19-8.76 μM. Nine compounds 1-4 and 10-14 displayed inhibition of COX-1 with IC₅₀ values ranging from 0.37 to 1.77 μM (lower than that of reference compound), whereas compounds 2, 10, 13 and 14 strongly inhibited the COX-2. The compounds 10-14 exhibited strong inhibitory activity against LOX enzyme. All compounds were evaluated for the inhibitory activities against LPS-induced TNF-α and IL-6 release in the macrophages. On the basis of screening results, five active compounds 3, 4, 12, 13 and 14 were found strong inhibitors of TNF-α and IL-6 release in a dose-dependent manner. Molecular docking experiments were performed to clarify the molecular aspects of the observed COX and LOX inhibitory activities of the investigated compounds. Present findings increases the possibility that these α,β-unsaturated carbonyl based compounds might serve as beneficial starting point for the design and development of improved anti-inflammatory agents.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  9. Jantan I, Bukhari SN, Adekoya OA, Sylte I
    Drug Des Devel Ther, 2014;8:1405-18.
    PMID: 25258510 DOI: 10.2147/DDDT.S67370
    Arachidonic acid metabolism leads to the generation of key lipid mediators which play a fundamental role during inflammation. The inhibition of enzymes involved in arachidonic acid metabolism has been considered as a synergistic anti-inflammatory effect with enhanced spectrum of activity. A series of 1,3-diphenyl-2-propen-1-one derivatives were investigated for anti-inflammatory related activities involving inhibition of secretory phospholipase A2, cyclooxygenases, soybean lipoxygenase, and lipopolysaccharides-induced secretion of interleukin-6 and tumor necrosis factor-alpha in mouse RAW264.7 macrophages. The results from the above mentioned assays exhibited that the synthesized compounds were effective inhibitors of pro-inflammatory enzymes and cytokines. The results also revealed that the chalcone derivatives with 4-methlyamino ethanol substitution seem to be significant for inhibition of enzymes and cytokines. Molecular docking experiments were carried out to elucidate the molecular aspects of the observed inhibitory activities of the investigated compounds. Present findings increase the possibility that these chalcone derivatives might serve as a beneficial starting point for the design and development of improved anti-inflammatory agents.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology*
  10. Shaari K, Suppaiah V, Wai LK, Stanslas J, Tejo BA, Israf DA, et al.
    Bioorg Med Chem, 2011 Nov 1;19(21):6340-7.
    PMID: 21958738 DOI: 10.1016/j.bmc.2011.09.001
    A bioassay-guided investigation of Melicope ptelefolia Champ ex Benth (Rutaceae) resulted in the identification of an acyphloroglucinol, 2,4,6-trihydroxy-3-geranylacetophenone or tHGA, as the active principle inhibiting soybean 15-LOX. The anti-inflammatory action was also demonstrated on human leukocytes, where the compound showed prominent inhibitory activity against human PBML 5-LOX, with an IC(50) value of 0.42 μM, very close to the effect produced by the commonly used standard, NDGA. The compound concentration-dependently inhibited 5-LOX product synthesis, specifically inhibiting cysteinyl leukotriene LTC(4) with an IC(50) value of 1.80 μM, and showed no cell toxicity effects. The anti-inflammatory action does not seem to proceed via redox or metal chelating mechanism since the compound tested negative for these bioactivities. Further tests on cyclooxygenases indicated that the compound acts via a dual LOX/COX inhibitory mechanism, with greater selectivity for 5-LOX and COX-2 (IC(50) value of 0.40 μM). The molecular features that govern the 5-LOX inhibitory activity was thus explored using in silico docking experiments. The residues Ile 553 and Hie 252 were the most important residues in the interaction, each contributing significant energy values of -13.45 (electrostatic) and -5.40 kcal/mol (electrostatic and Van der Waals), respectively. The hydroxyl group of the phloroglucinol core of the compound forms a 2.56Å hydrogen bond with the side chain of the carboxylate group of Ile 553. Both Ile 553 and Hie 252 are crucial amino acid residues which chelate with the metal ion in the active site. Distorting the geometry of these ligands could be the reason for the inhibition activity shown by tHGA. The molecular simulation studies supported the bioassay results and served as a good model for understanding the way tHGA binds in the active site of human 5-LOX enzyme.
    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
  11. Janbaz KH, Arif J, Saqib F, Imran I, Ashraf M, Zia-Ul-Haq M, et al.
    BMC Complement Altern Med, 2014 Feb 22;14:71.
    PMID: 24559094 DOI: 10.1186/1472-6882-14-71
    BACKGROUND: Isodon rugosus is used in folk Pakistan traditional practices to cure ailments related to gastrointestinal, respiratory and cardiovascular problems. Present study was undertaken to validate these folkloric uses.

    METHODS: A crude methanol extract of the aerial parts of Isodon rugosus (Ir.Cr.) was used for both in vitro and in vivo experiments. The plant extract was tested on isolated rabbit jejunum preparations for possible presence of spasmolytic activity. Moreover, isolated rabbit tracheal and aorta preparations were used to ascertain the relaxant effects of the extract. Acetylcholinesterase and butyrylcholinesterase inhibitory activities of Ir.Cr were also determined as well as its antioxidant activity. The in vivo antiemetic activity of the extract was evaluated by using the chick emesis model, while the analgesic and antipyretic activities were conducted on albino mice.

    RESULTS: The application of the crude extract of I. rugosus to isolated rabbit jejunum preparations exhibited relaxant effect (0.01-0.3 mg/ml). The Ir.Cr also relaxed K+(80 m M)-induced spastic contractions in isolated rabbit jejunum preparations and shifted the Ca+2 concentration response curves towards right (0.01-0.3 mg/ml). Similarly, the extract, when applied to the isolated rabbit tracheal preparations relaxed the carbachol (1 μM)--as well as K+ (80 mM)-induced contractions in a concentration range of 0.01-1.0 mg/ml. Moreover, it also relaxed (0.01-3.0 mg/ml) the phenylephrine (1 μM)- and K+ (80 mM)-induced contractions in isolated rabbit aorta preparations. The Ir.Cr (80 mg/kg) demonstrated antipyretic activity on pyrogen-induced pyrexia in rabbits as compared to aspirin as standard drug. The Ir.Cr also exhibited anti-oxidant as well as inhibitory effect on acetyl- and butyryl-cholinesterase and lipoxygenase (0.5 mg/ml).

    CONCLUSIONS: The observed relaxant effect on isolated rabbit jejunum, trachea and aorta preparations caused by Ir.Cr is possibly to be mediated through Ca+2 channel blockade and therefore may provided scientific basis to validate the folkloric uses of the plant in the management of gastrointestinal, respiratory and cardiovascular ailments. The observed antioxidant activity as well as the lipoxygenase inhibitory activity may validate its traditional use in pain and inflammations.

    Matched MeSH terms: Lipoxygenase Inhibitors/pharmacology
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