Displaying publications 21 - 31 of 31 in total

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  1. Thew HY, Boon Keat K, Tan YC, Ong YS, Parat MO, Murugaiyah V, et al.
    Chem Biol Interact, 2024 May 01;394:110978.
    PMID: 38552766 DOI: 10.1016/j.cbi.2024.110978
    Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) protein aggregates, leading to synaptic dysfunction and neuronal cell death. In this study, we used a comprehensive approach encompassing in vitro assays, computational analyses, and an in vivo Caenorhabditis elegans model to evaluate the inhibitory effects of various xanthones, focusing on Garcinone D (GD), on Aβ42 oligomer formation. Dot blot analysis revealed concentration-dependent responses among xanthones, with GD consistently inhibiting Aβ42 oligomer formation at low concentrations (0.1 and 0.5 μM, inhibitions of 84.66 ± 2.25% and 85.06 ± 6.57%, respectively). Molecular docking and dynamics simulations provided insights into the molecular interactions between xanthones and Aβ42, highlighting the disruption of key residues involved in Aβ42 aggregation. The neuroprotective potential of GD was established using transgenic C. elegans GMC101, with substantial delays in paralysis reported at higher concentrations. Our findings show that GD is a potent suppressor of Aβ42 oligomer formation, suggesting its potential as a therapeutic candidate for AD. The concentration-dependent effects observed in both in vitro and in vivo models underscore the need for nuanced dose-response assessments. These findings contribute novel insights into the therapeutic landscape of xanthones against AD, emphasizing the multifaceted potential of GD for further translational endeavors in neurodegenerative disorder research.
  2. Ng SL, Ong YS, Khaw KY, Teh SP, Tan CS, Ming LC, et al.
    Medicina (Kaunas), 2021 Feb 23;57(2).
    PMID: 33672384 DOI: 10.3390/medicina57020189
    The global pandemic of the coronavirus disease 2019 is a known consequence of infection of severe respiratory syndrome coronavirus-2 (SARS-CoV-2). It has affected nations worldwide with soaring number of cases daily. Symptoms such as fever, cough, and shortness of breath, diarrhea, nausea and vomiting are commonly presented in COVID-19 patients. This focused review aims to discuss these uncommon and atypical COVID-19 symptoms that may be presented which might affect neurological, cardiovascular, cutaneous and ocular systems and their possible mode of actions. Nonetheless, there are some cases of reported uncommon or atypical symptoms which may warrant healthcare professionals to be aware of, especially when in contact with patients. The knowledge and information concerning these symptoms might be able to provide additional cues for healthcare professional by subjecting patients to COVID-19 screening. Meanwhile, it might be able to further enhance the alertness and additional precautions being taken by healthcare personnel, which eventually lead to reduced risk of infections.
  3. Ng SL, Khaw KY, Ong YS, Goh HP, Kifli N, Teh SP, et al.
    J Evid Based Integr Med, 2021;26:2515690X21996662.
    PMID: 33787349 DOI: 10.1177/2515690X21996662
    The management of the global pandemic outbreak due to the coronavirus disease (COVID-19) has been challenging with no exact dedicated treatment nor established vaccines at the beginning of the pandemic. Nonetheless, the situation seems to be better controlled with the recent COVID-19 vaccines roll-out globally as active immunisation to prevent COVID-19. The extensive usage and trials done in recent outbreak in China has shown the effectiveness of traditional Chinese Medicines (TCM) in improving the wellbeing of COVID-19 patients. Therefore, COVID-19 Prevention and Treatment guidelines has listed a number of recommended concoctions meant for COVID-19 patients. Licorice, more commonly known as Gancao in Chinese Pinyin, is known as one of the most frequently used ingredients in TCM prescriptions for treatment of epidemic diseases. Interestingly, it is deemed as food ingredient as well, where it is normally used in Western cuisines' desserts and sweets. The surprising fact that licorice appeared in the top 10 main ingredients used in TCM prescriptions in COVID-19 has drawn great attention from researchers in revealing its biological potential in overcoming this disease. To date, there are no comprehensive review on licorice and its benefits when used in COVID-19. Thus, in this current review, the possible benefits, mechanism of actions, safety and limitations of licorice were explored in hope to provide a quick reference guide for its preclinical and clinical experimental set-up in this very critical moment of pandemic.
  4. Husna Hasnan MH, Sivasothy Y, Khaw KY, Nafiah MA, Hazni H, Litaudon M, et al.
    Int J Mol Sci, 2023 Jun 27;24(13).
    PMID: 37445877 DOI: 10.3390/ijms241310699
    Studies have been conducted over the last decade to identify secondary metabolites from plants, in particular those from the class of alkaloids, for the development of new anti-Alzheimer's disease (AD) drugs. The genus Alseodaphne, comprising a wide range of alkaloids, is a promising source for the discovery of new cholinesterase inhibitors, the first-line treatment for AD. With regard to this, a phytochemical investigation of the dichloromethane extract of the bark of A. pendulifolia Gamb. was conducted. Repeated column chromatography and preparative thin-layer chromatography led to the isolation of a new bisbenzylisoquinoline alkaloid, N-methyl costaricine (1), together with costaricine (2), hernagine (3), N-methyl hernagine (4), corydine (5), and oxohernagine (6). Their structures were elucidated by the 1D- and 2D-NMR techniques and LCMS-IT-TOF analysis. Compounds 1 and 2 were more-potent BChE inhibitors than galantamine with IC50 values of 3.51 ± 0.80 µM and 2.90 ± 0.56 µM, respectively. The Lineweaver-Burk plots of compounds 1 and 2 indicated they were mixed-mode inhibitors. Compounds 1 and 2 have the potential to be employed as lead compounds for the development of new drugs or medicinal supplements to treat AD.
  5. Nawaz M, Hayat S, Farooq U, Iqbal MA, Khalid SH, Nee TW, et al.
    RSC Adv, 2024 Oct 09;14(44):32008-32020.
    PMID: 39391623 DOI: 10.1039/d4ra04816d
    The current study focuses on assessing the activity of the N-alkylated benzimidazole based cubosomal hydrogel (cubogel) for the topical treatment of burn wounds. The study involves the synthesis of six benzimidazole derivatives (1-6) and their characterization by FT-IR and 1H and 13C NMR spectroscopy. The further study involves the design and formation of nanoparticles known as cubosomes loaded with selected 1-benzyl-1-benzimidazole (API 6) and the development of a cubogel for the topical treatment of burn wounds. Cubosomes were prepared by the homogenization method, using glyceryl monooleate (GMO) as a lipid polymer and poloxamer 407 (P407) as a surfactant. Cubosomes undergo in vitro characterizations (measurement of particle size, zeta potential, polydispersity index (PDI), % entrapment efficiency, drug release in phosphate buffer saline of pH 6.8, and surface morphology by utilizing TEM (transmission electron microscopy). Formulation D3 (2.5% of GMO, 1% of P407, and 2.5% of PVA) emerged as the optimized formulation, displaying a minimum particle size (PS) of 129.9 ± 1 nm, entrapment efficiency (%EE) of 96.67 ± 0.89%, and a drug release of 86 ± 2.7% at 24 h. Carbopol 940 hydrogel was prepared and incorporated with the optimized formulation to prepare cubogel. This optimized cubogel provided 92.56 ± 0.014% in vitro drug release within 24 h. An in vivo histopathological study was conducted on an animal model (rabbit) to assess the efficacy of cubogel in wound healing and wound contraction. Then cubogel was compared with the commercially available creams Clotrimazole® and Polyfax®. The wound treated with newly developed cubogel has maximum wound contraction (96.70%) as compared to the standard creams. The findings revealed that the newly formulated cubogel was highly effective in treating burns, showing superior performance to commercial products without inducing side effects. Additionally, benzimidazole derivative loaded cubogel caused a sustained release for treating burn wounds without any bacterial infections. The current results further suggested phase 0 clinical trials.
  6. Leong ST, Liew SY, Khaw KY, Ahmad Hassali H, Richomme P, Derbré S, et al.
    Bioorg Chem, 2023 Dec;141:106859.
    PMID: 37742494 DOI: 10.1016/j.bioorg.2023.106859
    A bio-assay guided fractionation strategy based on cholinesterase assay combined with 13C NMR-based dereplication was used to identify active metabolites from the bark of Mesua lepidota. Eight compounds were identified with the aid of the 13C NMR-based dereplication software, MixONat, i.e., sitosterol (1), stigmasterol (2), α-amyrin (3), friedelin (6), 3β-friedelinol (7), betulinic acid (9), lepidotol A (10) and lepidotol B (11). Further bio-assay guided isolation of active compounds afforded one xanthone, pyranojacareubin (12) and six coumarins; lepidotol A (10), lepidotol B (11), lepidotol E (13), lepidotin A (14), and lepidotin B (15), including a new Mammea coumarin, lepidotin C (16). All the metabolites showed strong to moderate butyrylcholinesterase (BChE) inhibition. Lepidotin B (15) exhibited the most potent inhibition towards BChE with a mix-mode inhibition profile and a Ki value of 1.03 µM. Molecular docking and molecular dynamics simulations have revealed that lepidotin B (15) forms stable interactions with key residues within five critical regions of BChE. These regions encompass residues Asp70 and Tyr332, the acyl hydrophobic pocket marked by Leu286, the catalytic triad represented by Ser198 and His438, the oxyanion hole (OH) constituted by Gly116 and Gly117, and the choline binding site featuring Trp82. To gauge the binding strength of lepidotin B (15) and to pinpoint pivotal residues at the binding interface, free energy calculations were conducted using the Molecular Mechanics Generalized Born Surface Area (MM-GBSA) approach. This analysis not only predicted a favourable binding affinity for lepidotin B (15) but also facilitated the identification of significant residues crucial for the binding interaction.
  7. Kong YR, Jong YX, Balakrishnan M, Bok ZK, Weng JKK, Tay KC, et al.
    Biology (Basel), 2021 Apr 01;10(4).
    PMID: 33916114 DOI: 10.3390/biology10040287
    Oxidative stress is a result of disruption in the balance between antioxidants and pro-oxidants in which subsequently impacting on redox signaling, causing cell and tissue damages. It leads to a range of medical conditions including inflammation, skin aging, impaired wound healing, chronic diseases and cancers but these conditions can be managed properly with the aid of antioxidants. This review features various studies to provide an overview on how Carica papaya help counteract oxidative stress via various mechanisms of action closely related to its antioxidant properties and eventually improving the management of various oxidative stress-related health conditions. Carica papaya is a topical plant species discovered to contain high amounts of natural antioxidants that can usually be found in their leaves, fruits and seeds. It contains various chemical compounds demonstrate significant antioxidant properties including caffeic acid, myricetin, rutin, quercetin, α-tocopherol, papain, benzyl isothiocyanate (BiTC), and kaempferol. Therefore, it can counteract pro-oxidants via a number of signaling pathways that either promote the expression of antioxidant enzymes or reduce ROS production. These signaling pathways activate the antioxidant defense mechanisms that protect the body against both intrinsic and extrinsic oxidative stress. To conclude, Carica papaya can be incorporated into medications or supplements to help manage the health conditions driven by oxidative stress and further studies are needed to investigate the potential of its chemical components to manage various chronic diseases.
  8. Maran S, Ee R, Faten SA, Sy Bing C, Khaw KY, Erin Lim SH, et al.
    PLoS One, 2020;15(4):e0230982.
    PMID: 32315303 DOI: 10.1371/journal.pone.0230982
    Atrial septal defect (ASD) is one of the most common congenital heart defects diagnosed in children. Sarcomeric genes has been attributed to ASD and knockdown of MYH3 functionally homologues gene in chick models indicated abnormal atrial septal development. Here, we report for the first time, a case-control study investigating the role of MYH3 among non-syndromic ASD patients in contributing to septal development. Four amplicons which will amplifies the 40 kb MYH3 were designed and amplified using long range-PCR. The amplicons were then sequenced using indexed paired-end libraries on the MiSeq platform. The STREGA guidelines were applied for planning and reporting. The non-synonymous c. 3574G>A (p.Ala1192Thr) [p = 0.001, OR = 2.30 (1.36-3.87)] located within the tail domain indicated a highly conserved protein region. The mutant model of c. 3574G>A (p.Ala1192Thr) showed high root mean square deviation (RMSD) values compared to the wild model. To our knowledge, this is the first study to provide compelling evidence on the pathogenesis of MYH3 variants towards ASD hence, suggesting the crucial role of non-synonymous variants in the tail domain of MYH3 towards atrial septal development. It is hoped that this gene can be used as panel for diagnosis of ASD in future.
  9. Loh JS, Mak WQ, Tan LKS, Ng CX, Chan HH, Yeow SH, et al.
    Signal Transduct Target Ther, 2024 Feb 16;9(1):37.
    PMID: 38360862 DOI: 10.1038/s41392-024-01743-1
    The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.
  10. Osman N, Awang K, Khaw KY, Qi Mak W, Tiamas SG, Maulana S, et al.
    Nat Prod Res, 2024 Aug 21.
    PMID: 39165195 DOI: 10.1080/14786419.2024.2394096
    This study investigated the butyrylcholinesterase (BChE) inhibitory activity of harmane (1), naucledine (2), and dihydrodeglycocadambine (3) isolated from fractions F7 and F9 of Ochreinauclea maingayi. Both fractions demonstrated significant inhibition, exceeding 80%, against BChE at 100 µg/mL. Compound 2, is the most potent inhibitor, exhibiting an IC50 value of 22.08 µM, followed by 1 and 3 (IC50 23.96 and 30.32 µM, respectively). Docking studies revealed that 1 and 2 effectively bind to BChE, with binding energies of -51.24 and -57.17 kcal/mol, respectively. Kinetic analysis of 2 indicated mixed-mode inhibition of BChE, with a Ki of 6.08 μM. In the paralysis assay, 1 showed a weak delay in paralysis and reduced the paralysis ratio from 72.59 ± 4.7% to 60.00 ± 7.0% (12.59% reduction) followed by 2 with 70.00 ± 1.7% (2.59% reduction) compared with negative standard (DMSO 0.1%) on human amyloid β-protein in a transgenic Caenorhabditis elegans (CL4176) model.
  11. Low LE, Kong CK, Yap WH, Siva SP, Gan SH, Siew WS, et al.
    Chem Biol Interact, 2023 Dec 01;386:110750.
    PMID: 37839513 DOI: 10.1016/j.cbi.2023.110750
    Hydroxychloroquine (HCQ) is a unique class of medications that has been widely utilized for the treatment of cancer. HCQ plays a dichotomous role by inhibiting autophagy induced by the tumor microenvironment (TME). Preclinical studies support the use of HCQ for anti-cancer therapy, especially in combination with conventional anti-cancer treatments since they sensitize tumor cells to drugs, potentiating the therapeutic activity. However, clinical evidence has suggested poor outcomes for HCQ due to various obstacles, including non-specific distribution, low aqueous solubility and low bioavailability at target sites, transport across tissue barriers, and retinal toxicity. These issues are addressable via the integration of HCQ with nanotechnology to produce HCQ-conjugated nanomedicines. This review aims to discuss the pharmacodynamic, pharmacokinetic and antitumor properties of HCQ. Furthermore, the antitumor performance of the nanoformulated HCQ is also reviewed thoroughly, aiming to serve as a guide for the HCQ-based enhanced treatment of cancers. The nanoencapsulation or nanoconjugation of HCQ with nanoassemblies appears to be a promising method for reducing the toxicity and improving the antitumor efficacy of HCQ.
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