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  1. Narayanaswamy R, Wai LK, Esa NM
    Pharmacogn Mag, 2017 Oct;13(Suppl 3):S512-S518.
    PMID: 29142407 DOI: 10.4103/pm.pm_195_16
    Background: The phytoconstituents phytic acid and 4-hydroxyisoleucine have been reported to posses various biological properties.

    Objective: This prompted us to carry out the docking study on these two ligands (phytic acid & 4-hydroxyisoleucine) against eleven targeted enzymes.

    Materials and Methods: Phytic acid & 4-hydroxyisoleucine were evaluated on the docking behaviour of cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-2 (mPGES-2), tyrosinase, human neutrophil elastase (HNE), matrix metalloproteinase (MMP 2 and 9), xanthine oxidase (XO), squalene synthase (SQS), nitric oxide synthase (NOS), human aldose reductase (HAR) and lipoxygenase (LOX) using Discovery Studio Version 3.1 (except for LOX, where Autodock 4.2 tool was used).

    Results: Docking and binding free energy analysis revealed that phytic acid exhibited the maximum binding energy for four target enzymes such as COX-2, mPGES-2, tyrosinase and HNE. Interestingly, we found that 4-hydroxyisoleucine has the potential to dock and bind with all of the eleven targeted enzymes.

    Conclusion: This present study has paved a new insight in understanding 4-hydroxyisoleucine as potential inhibitor against COX-2, mPGES-2, tyrosinase, HNE, MMP 2, MMP 9, XO, SQS, NOS, HAR and LOX.

    SUMMARY: 4-hydroxyisoleucine has the potential to dock and bind with all 11targeted enzymes such as (cyclooxygenase-2 [COX-2], microsomal prostaglandin E synthase-2 [mPGES-2], tyrosinase, human neutrophil elastase [HNE], matrix metalloproteinase [MMP-2 and -9], xanthine oxidase, squalene synthase, nitric oxide synthase, human aldose reductase, and lipoxygenase)Moreover, docking studies and binding free energy calculations revealed that phytic acid exhibited the maximum binding energy for four target enzymes such as COX-2, mPGES-2, tyrosinase, and HNE; however, for other six target enzymes, it fails to dock. Abbreviations used: COX-2: Cyclooxygenase-2, mPGES-2: Microsomal prostaglandin E synthase-2, HNE: Human neutrophil elastase, MMP-2 and -9: Matrix metalloproteinase-2 and -9, XO: Xanthine oxidase, SQS: Squalene synthase, NOS: Nitric oxide synthase, HAR: Human aldose reductase, LOX: Lipoxygenase, ADME: Absorption, distribution, metabolism, and excretion, TOPKAT: Toxicity Prediction by Computer-assisted Technology.

  2. Narayanaswamy R, Shymatak M, Chatterjee S, Wai LK, Arumugam G
    Adv Pharm Bull, 2014 Dec;4(Suppl 2):543-8.
    PMID: 25671187 DOI: 10.5681/apb.2014.080
    In recent year's anti-angiogenesis agents have been recognized as effective drugs for the treatment of solid tumors, this prompted us to conduct the present study.
  3. Narayanaswamy R, Isha A, Wai LK, Ismail IS
    Pharmacogn Mag, 2016 Jan;12(Suppl 1):S21-6.
    PMID: 27041853 DOI: 10.4103/0973-1296.176111
    Clinacanthus nutans (Burm. f.) Lindau has gained popularity among Malaysians as a traditional plant for anti-inflammatory activity.
  4. Bukhari SN, Jantan I, Wai LK, Lajis NH, Abbas F, Jasamai M
    Med Chem, 2013 Dec;9(8):1091-8.
    PMID: 23092331
    A series of novel isoxazole and pyrazoline derivatives has been synthesized and evaluated for their effects on the chemiluminescence and chemotactic activity of human phagocytes. Their effects on the chemotactic migration of isolated polymorphonuclear leukocytes (PMNs) and on the release of reactive oxygen species (ROS) during respiratory burst of human whole blood and PMNs were carried out using the Boyden chamber technique and luminol-based chemiluminescence assay, respectively. Of the compounds tested, compounds 8, 9, 11 and 12 exhibited higher inhibitory activity on the release of ROS (with IC50 values ranging from 5.6 to 8.4 μM) than acetylsalicylic acid (IC50 = 9.5 μ M). These compounds also showed strong inhibitory activity on the migration of PMNs with compound 8 exhibiting an IC50 value lower than that of ibuprofen. The results suggest that some of these isoxazole and pyrazoline derivatives have ability to modulate the innate immune response of phagocytes at different steps, indicating their potential as a source of new immunomodulatory agents.
  5. Ahmad N, Wee CE, Wai LK, Zin NM, Azmi F
    Carbohydr Polym, 2021 Feb 15;254:117299.
    PMID: 33357867 DOI: 10.1016/j.carbpol.2020.117299
    Naturally derived antimicrobial peptides (AMPs) are an attractive source of new antimicrobial agents. However, clinical application of AMPs is associated with poor bioavailability and toxicity. In this study, we address these limitations by designing a new series of chitosan derivatives to mimic the amphiphilic topology of AMPs. The synthesized chitosan derivatives were found to self-assemble into nanoparticles in the aqueous environment. Among the compounds, a chitosan derivative grafted with arginine and oleic acid (CH-Arg-OA) exhibited the most potent antimicrobial activity, especially against Gram-negative bacteria. It also caused minimal cell death when tested in HEK293 and HepG2 cell lines, thus confirming the role of cationicity and lipophilicity for selective bacteria targeting. CH-Arg-OA exhibited its antimicrobial activity by disrupting bacterial membranes and causing the leakage of cytoplasmic contents. Thus, amphiphilic chitosan nanoparticles offer a great promise as a new class of AMPs mimics that is effective against Gram-negative bacteria.
  6. Rehman K, Aluwi MF, Rullah K, Wai LK, Mohd Amin MC, Zulfakar MH
    Int J Pharm, 2015 Jul 25;490(1-2):131-41.
    PMID: 26003416 DOI: 10.1016/j.ijpharm.2015.05.045
    Imiquimod is a chemotherapeutic agent for many skin-associated diseases, but it has also been associated with inflammatory side effects. The aim of this study was to prevent the inflammatory effect of commercial imiquimod (Aldara(®)) by controlled release of imiquimod through a hydrogel/oleogel colloidal mixture (CA bigel) containing fish oil as an anti-inflammatory agent. Imiquimod permeability from Aldara® cream and bigel through mice skin was evaluated, and the drug content residing in the skin via the tape stripping technique was quantified. The fish oil fatty acid content in skin along with its lipophilic environment was also determined. An inflammation study was conducted using animal models, and Aldara(®) cream was found to potentially cause psoriasis-like inflammation, which could be owing to prolonged application and excessive drug permeation. Controlled release of imiquimod along with fish oil through CA bigel may have caused reduced imiquimod inflammation. NMR studies and computerized molecular modeling were also conducted to observe whether the fish oil and imiquimod formed a complex that was responsible for improving imiquimod transport and reducing its side effects. NMR spectra showed dose-dependent chemical shifts and molecular modeling revealed π-σ interaction between EPA and imiquimod, which could help reduce imiquimod inflammation.
  7. Huq AM, Wai LK, Rullah K, Mohd Aluwi MFF, Stanslas J, Jamal JA
    Chem Biol Drug Des, 2019 03;93(3):222-231.
    PMID: 30251480 DOI: 10.1111/cbdd.13404
    Hormone replacement therapy has been a conventional treatment for postmenopausal symptoms in women. However, it has potential risks of breast and endometrial cancers. The aim of this study was to evaluate the oestrogenicity of a plant-based compound, mimosine, in MCF-7 cells by in silico model. Cell viability and proliferation, ERα-SRC1 coactivator activity and expression of specific ERα-dependent marker TFF1 and PGR genes were evaluated. Binding modes of 17β-oestradiol and mimosine at the ERα ligand binding domain were compared using docking and molecular dynamics simulation experiments followed by binding interaction free energy calculation with molecular mechanics/Poisson-Boltzmann surface area. Mimosine showed increased cellular viability (64,450 cells/ml) at 0.1 μM with significant cell proliferation (120.5%) compared to 17β-oestradiol (135.2%). ER antagonist tamoxifen significantly reduced proliferative activity mediated by mimosine (49.9%). Mimosine at 1 μM showed the highest ERα binding activity through increased SRC1 recruitment at 186.9%. It expressed TFF1 (11.1-fold at 0.1 μM) and PGR (13.9-fold at 0.01 μM) genes. ERα-mimosine binding energy was -49.9 kJ/mol, and it interacted with Thr347, Gly521 and His524 of ERα-LBD. The results suggested that mimosine has oestrogenic activity.
  8. Jantan I, Bukhari SN, Lajis NH, Abas F, Wai LK, Jasamai M
    J Pharm Pharmacol, 2012 Mar;64(3):404-12.
    PMID: 22309272 DOI: 10.1111/j.2042-7158.2011.01423.x
    A series of 43 curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on the chemiluminescence and chemotactic activity of phagocytes in vitro.
  9. Zulfakar MH, Chan LM, Rehman K, Wai LK, Heard CM
    AAPS PharmSciTech, 2018 Apr;19(3):1116-1123.
    PMID: 29181705 DOI: 10.1208/s12249-017-0923-x
    Coenzyme Q10 (CoQ10) is a vitamin-like oil-soluble molecule that has anti-oxidant and anti-ageing effects. To determine the most optimal CoQ10 delivery vehicle, CoQ10 was solubilised in both water and fish oil, and formulated into hydrogel, oleogel and bigel. Permeability of CoQ10 from each formulation across porcine ear skin was then evaluated. Furthermore, the effects of the omega-3 fatty eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids from fish oil on skin permeation were investigated by means of nuclear magnetic resonance (NMR) and computerised molecular modelling docking experiments. The highest drug permeation was achieved with the bigel formulation that proved to be the most effective vehicle in delivering CoQ10 across the skin membrane due to a combination of its adhesive, viscous and lipophilic properties. Furthermore, the interactions between CoQ10 and fatty acids revealed by NMR and molecular modelling experiments likely accounted for skin permeability of CoQ10. NMR data showed dose-dependent changes in proton chemical shifts in EPA and DHA. Molecular modelling revealed complex formation and large binding energies between fatty acids and CoQ10. This study advances the knowledge about bigels as drug delivery vehicles and highlights the use of NMR and molecular docking studies for the prediction of the influence of drug-excipient relationships at the molecular level.
  10. Yan MP, Wee CE, Yen KP, Stevens A, Wai LK
    Future Med Chem, 2023 Nov;15(21):1987-2009.
    PMID: 37933551 DOI: 10.4155/fmc-2023-0202
    G-quadruplexes (G4s) within the human genome have undergone extensive molecular investigation, with a strong focus on telomeres, gene promoters and repetitive regulatory sequences. G4s play central roles in regulating essential biological processes, including telomere maintenance, replication, transcription and translation. Targeting these molecular processes with G4-binding ligands holds substantial therapeutic potential in anticancer treatments and has also shown promise in treating neurological, skeletal and muscular disorders. The presence of G4s in bacterial and viral genomes also suggests that G4-binding ligands could be a critical tool in fighting infections. This review provides an overview of the progress and applications of G4-binding ligands, their proposed mechanisms of action, challenges faced and prospects for their utilization in anticancer treatments, neurological disorders and antiviral activities.
  11. Salga SM, Ali HM, Abdullah MA, Abdelwahab SI, Wai LK, Buckle MJ, et al.
    Molecules, 2011 Nov 07;16(11):9316-30.
    PMID: 22064271 DOI: 10.3390/molecules16119316
    Some novel Schiff bases derived from 1-(2-ketoiminoethyl)piperazines were synthesized and characterized by mass spectroscopy, FTIR, UV-Visible, 1H and 13C-NMR. The compounds were tested for inhibitory activities on human acetylcholinesterase (hAChE), antioxidant activities, acute oral toxicity and further studied by molecular modeling techniques. The study identified the compound (DHP) to have the highest activity among the series in hAChE inhibition and DPPH assay while the compound LP revealed the highest activity in the FRAP assay. The hAChE inhibitory activity of DHP is comparable with that of propidium, a known AChE inhibitor. This high activity of DHP was checked by molecular modeling which showed that DHP could not be considered as a bivalent ligand due to its incapability to occupy the esteratic site (ES) region of the 3D crystal structure of hAChE. The antioxidant study unveiled varying results in 1,1-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. This indicates mechanistic variations of the compounds in the two assays. The potential therapeutic applications and safety of these compounds were suggested for use as human acetylcholinesterase inhibitors and antioxidants.
  12. Nwaefulu ON, Al-Shar'i NA, Owolabi JO, Sagineedu SR, Woei LC, Wai LK, et al.
    J Mol Model, 2022 Oct 04;28(11):340.
    PMID: 36194315 DOI: 10.1007/s00894-022-05326-1
    Cancer is imposing a global health burden because of the steady increase in new cases. Moreover, current anticancer therapeutics are associated with many drawbacks, mainly the emergence of resistance and the severe adverse effects. Therefore, there is a continuous need for developing new anticancer agents with novel mechanisms of action and lower side effects. Natural products have been a rich source of anticancer medication. Cycleanine, a natural product, was reported to exert an antiproliferative effect on ovarian cancer cells by causing apoptosis through activation of caspases 3/7 and cleavage of poly (ADP-ribose) polymerase to form poly (ADP-ribose) polymerase-1 (PARP1). It is well-established that PARP1 is associated with carcinogenesis, and different PARP1 inhibitors are approved as anticancer drugs. In this study, the cytotoxic activity of cycleanine was computationally investigated to determine whether it is a PARP1 inhibitor or a caspase activator. Molecular docking and molecular dynamics (MD) simulations were utilized for this purpose. The results showed that cycleanine has a good binding affinity to PARP1; moreover, MD simulation showed that it forms a stable complex with the enzyme. Consequently, the results showed that cycleanine is a potential inhibitor of the PARP1 enzyme.
  13. Leong SW, Faudzi SM, Abas F, Aluwi MF, Rullah K, Wai LK, et al.
    Molecules, 2014 Oct 09;19(10):16058-81.
    PMID: 25302700 DOI: 10.3390/molecules191016058
    A series of ninety-seven diarylpentanoid derivatives were synthesized and evaluated for their anti-inflammatory activity through NO suppression assay using interferone gamma (IFN-γ)/lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Twelve compounds (9, 25, 28, 43, 63, 64, 81, 83, 84, 86, 88 and 97) exhibited greater or similar NO inhibitory activity in comparison with curcumin (14.7 ± 0.2 µM), notably compounds 88 and 97, which demonstrated the most significant NO suppression activity with IC50 values of 4.9 ± 0.3 µM and 9.6 ± 0.5 µM, respectively. A structure-activity relationship (SAR) study revealed that the presence of a hydroxyl group in both aromatic rings is critical for bioactivity of these molecules. With the exception of the polyphenolic derivatives, low electron density in ring-A and high electron density in ring-B are important for enhancing NO inhibition. Meanwhile, pharmacophore mapping showed that hydroxyl substituents at both meta- and para-positions of ring-B could be the marker for highly active diarylpentanoid derivatives.
  14. 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.
  15. Rullah K, Mohd Aluwi MF, Yamin BM, Abdul Bahari MN, Wei LS, Ahmad S, et al.
    Bioorg Med Chem Lett, 2014 Aug 15;24(16):3826-34.
    PMID: 25027933 DOI: 10.1016/j.bmcl.2014.06.061
    The discovery of potent inhibitors of prostaglandin E2 (PGE2) synthesis in recent years has been proven to be an important game changer in pharmaceutical industry. It is known that excessive production of PGE2 triggers a vast array of biological signals and physiological events that contributes to inflammatory diseases such as rheumatoid arthritis, atherosclerosis, cancer, and pain. In this Letter, we report the synthesis of a series of minor prenylated chalcones and flavonoids which was found to be significantly active in suppressing the PGE2 production secreted by lipopolysaccharide-induced mouse macrophage cells (RAW 264.7). Among the compounds tested, 14b showed a dose-response inhibition of PGE2 production with an IC50 value of 2.1 μM. The suppression upon PGE2 secretion was not due to cell death since 14b did not reduce the cell viability in close proximity to the PGE2 inhibition concentration. The obtained atomic coordinates for the single-crystal XRD of 14b was then applied in the docking simulation to determine the potential important binding interactions with murine COX-2 and mPGES-1 putative binding sites.
  16. Mohd Faudzi SM, Leong SW, Auwal FA, Abas F, Wai LK, Ahmad S, et al.
    Arch Pharm (Weinheim), 2021 Jan;354(1):e2000161.
    PMID: 32886410 DOI: 10.1002/ardp.202000161
    A new series of pyrazole, phenylpyrazole, and pyrazoline analogs of diarylpentanoids (excluding compounds 3a, 4a, 5a, and 5b) was pan-assay interference compounds-filtered and synthesized via the reaction of diarylpentanoids with hydrazine monohydrate and phenylhydrazine. Each analog was evaluated for its anti-inflammatory ability via the suppression of nitric oxide (NO) on IFN-γ/LPS-activated RAW264.7 macrophage cells. The compounds were also investigated for their inhibitory capability toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), using a modification of Ellman's spectrophotometric method. The most potent NO inhibitor was found to be phenylpyrazole analog 4c, followed by 4e, when compared with curcumin. In contrast, pyrazole 3a and pyrazoline 5a were found to be the most selective and effective BChE inhibitors over AChE. The data collected from the single-crystal X-ray diffraction analysis of compound 5a were then applied in a docking simulation to determine the potential binding interactions that were responsible for the anti-BChE activity. The results obtained signify the potential of these pyrazole and pyrazoline scaffolds to be developed as therapeutic agents against inflammatory conditions and Alzheimer's disease.
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