Displaying all 19 publications

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  1. Poh YW, Gan SY, Tan EL
    Exp Oncol, 2012 Jul;34(2):85-9.
    PMID: 23013758
    The aim of this study is to investigate whether IL-6, IL-10 and TGF-β are able to confer resistance to apoptosis in nasopharyngeal carcinoma cells by upregulating the expression of survivin.
  2. Tan JK, Tan EL, Gan SY
    Exp Oncol, 2014 Sep;36(3):170-3.
    PMID: 25265349
    Deregulation of microRNA has been associated with cancer progression and the modification of cancer phenotypes could be achieved by targeting microRNA expression. This study aimed to determine the effects of miR-372 on cell progression and gene expression in nasopharyngeal carcinoma cell line, TW01.
  3. Chew MM, Gan SY, Khoo AS, Tan EL
    BMC Cancer, 2010;10:574.
    PMID: 20964870 DOI: 10.1186/1471-2407-10-574
    Nasopharyngeal carcinoma (NPC) is a type of neoplasm that is highly prevalent in East Asia and Africa with Epstein-Barr virus (EBV), genetic, and dietary factors implicated as possible aetiologic factors. Previous studies suggested the association of certain cytokines with the invasion and metastatic properties of NPC. The present study examined the roles of EBV latent membrane protein-1 (LMP1), interleukin-6 (IL-6), interleukin-10 (IL-10), transforming growth factor-beta 1 (TGF-β1) and laminin in the regulation of matrix-metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) in NPC. The effects of these factors on bmi-1, an oncogene, and ngx6, a tumour suppressor gene, were also investigated.
  4. Lee KT, Tan JK, Lam AK, Gan SY
    Crit Rev Oncol Hematol, 2016 Jul;103:1-9.
    PMID: 27179594 DOI: 10.1016/j.critrevonc.2016.04.006
    Despite significant medical advancement, nasopharyngeal carcinoma (NPC) remains one of the most difficult cancers to detect and treat where it continues to prevail especially among the Asian population. miRNAs could act as tumour suppressor genes or oncogenes in NPC. They play important roles in the pathogenesis of NPC by regulating specific target genes which are involved in various cellular processes and pathways. In particular, studies on miRNAs related to the Epstein Barr virus (EBV)-encoded latent membrane protein one (LMP1) and EBVmiRNA- BART miRNA confirmed the link between EBV and NPC. Both miRNA and its target genes could potentially be exploited for prognostic and therapeutic strategies. They are also important in predicting the sensitivity of NPC to radiotherapy and chemotherapy. The detection of stable circulating miRNAs in plasma of NPC patients has raised the potential of miRNAs as novel diagnostic markers. To conclude, understanding the roles of miRNA in NPC will identify ways to improve the management of patients with NPC.
  5. Yap JKY, Pickard BS, Gan SY, Chan EWL
    Int J Biochem Cell Biol, 2021 07;136:106014.
    PMID: 34022435 DOI: 10.1016/j.biocel.2021.106014
    Alzheimer's disease is an irreversible neurodegenerative disease, which accounts for most dementia cases. Neuroinflammation is increasingly recognised for its roles in Alzheimer's disease pathogenesis which, in part, links amyloid-beta to neuronal death. Neuroinflammatory signalling can be exhibited by neurons themselves, potentially leading to widespread neuronal cell death, although neuroinflammation is commonly associated with glial cells. The presence of the inflammasomes such as nucleotide-binding leucine-rich repeat receptors protein 1 in neurons accelerates amyloid-beta -induced neuroinflammation and has been shown to trigger neuronal pyroptosis in murine Alzheimer's disease models. However, the pathways involved in amyloid-beta activation of inflammasomes have yet to be elucidated. In this study, a gene trap mutagenesis approach was utilised to resolve the genes functionally involved in inflammasome signalling within neurons, and the mechanism behind amyloid-beta-induced neuronal death. The results indicate that amyloid-beta significantly accelerated neuroinflammatory cell death in the presence of a primed inflammasome (the NLR family pyrin domain-containing 1). The mutagenesis screen discovered the atypical mitochondrial Ras homolog family member T1 as a significant contributor to amyloid-beta-induced inflammasome -mediated neuronal death. The mutagenesis screen also identified two genes involved in transforming growth factor beta signalling, namely Transforming Growth Factor Beta Receptor 1 and SNW domain containing 1. Additionally, a gene associated with cytoskeletal reorganisation, SLIT-ROBO Rho GTPase Activating Protein 3 was found to be neuroprotective. In conclusion, these genes could play important roles in inflammasome signalling in neurons, which makes them promising therapeutic targets for future drug development against neuroinflammation in Alzheimer's disease.
  6. Gan SY, Wong LZ, Wong JW, Tan EL
    Int J Biol Macromol, 2019 Jan;121:207-213.
    PMID: 30300695 DOI: 10.1016/j.ijbiomac.2018.10.021
    Alzheimer's disease (AD) is a neurodegenerative disease that leads to progressive loss of neurons which often results in deterioration of memory and cognitive function. The development of AD is highly associated with the formation of senile plaques and neurofibrillary tangles. Amyloid β (Aβ) induces neurotoxicity and contributes to the development of AD. Recent evidences also highlighted the importance of neuroglobin (Ngb) in ameliorating AD. This study assessed the ability of fucosterol, a phytosterol found in brown alga, in protecting SH-SY5Y cells against Aβ-induced neurotoxicity. Its effects on the mRNA levels of APP and Ngb as well as the intracellular Aβ levels were also determined in Aβ-induced SH-SY5Y cells. SH-SY5Y cells were exposed to fucosterol prior to Aβ treatment. The effect on apoptosis was determined using Annexin V FITC staining and mRNA expression was studied using RT-PCR. Flow cytometry confirmed the protective effects of fucosterol on SH-SY5Y cells against Aβ-induced apoptosis. Pretreatment with fucosterol increased the Ngb mRNA levels but reduced the levels of APP mRNA and intracellular Aβ in Aβ-induced SH-SY5Y cells. These observations demonstrated the protective properties of fucosterol against Aβ-induced neurotoxicity in neuronal cells.
  7. Chan EWL, Krishnansamy S, Wong C, Gan SY
    Neurotoxicology, 2019 01;70:91-98.
    PMID: 30408495 DOI: 10.1016/j.neuro.2018.11.001
    The cognitive impairment caused by Alzheimer's disease (AD) is associated with beta-amyloid (Aβ) and tau proteins, and is accompanied by inflammation. Recently, a novel inflammasome signaling pathway has been uncovered. Inflammasomes are implicated in the execution of inflammatory responses and pyroptotic death leading to neurodegeneration. Thus, the inflammasome signaling pathway could be a potential therapeutic target for AD. Neural stem cells (NSCs) are multipotent cells that can self-renew and differentiate into distinct neural cells. NSC therapy has been considered to be a promising therapeutic approach in protecting the central nervous system and restoring it following damage. However, the mechanisms involved remain unclear. The aims of this study were to investigate the protective effects of NE4C neural stem cells against microglia-mediated neurotoxicity and to explore molecular mechanisms mediating their actions. NE4C decreased the levels of caspase-1 and IL-1β, and attenuated the level of the NLRP3 inflammasome and its associated protein adapter, apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) in LPS-stimulated BV2 microglial cells, possibly by regulating the phosphorylation of p38α MAPK. The conditioned media obtained from co-culture of LPS-stimulated BV2 and NE4C cells exhibited protective effects on SH-SY5Y cells against microglia-mediated neurotoxicity; this was associated with an attenuation of tau phosphorylation and amyloidogenesis and accompanied by down-regulation of GSK-3β and p38α MAPK signalling pathways. In conclusion, the present study suggested that NSC therapy could be a potential strategy against microglia-mediated neurotoxicity. NSCs regulate NLRP3 activation and IL-1β secretion, which are critical in the initiation of the inflammatory responses, hence preventing the release of neurotoxic pro-inflammatory factors by microglia. This eventually reduces tau hyperphosphylation and amyloidogenesis, possibly through the regulation of GSK-3β and p38α MAPK signalling pathways, and thus protects SH-SY5Y cells against microglia-mediated neurotoxicity.
  8. Yap JKY, Pickard BS, Chan EWL, Gan SY
    Mol Neurobiol, 2019 Nov;56(11):7741-7753.
    PMID: 31111399 DOI: 10.1007/s12035-019-1638-7
    The innate immune system and inflammatory response in the brain have critical impacts on the pathogenesis of many neurodegenerative diseases including Alzheimer's disease (AD). In the central nervous system (CNS), the innate immune response is primarily mediated by microglia. However, non-glial cells such as neurons could also partake in inflammatory response independently through inflammasome signalling. The NLR family pyrin domain-containing 1 (NLRP1) inflammasome in the CNS is primarily expressed by pyramidal neurons and oligodendrocytes. NLRP1 is activated in response to amyloid-β (Aβ) aggregates, and its activation subsequently cleaves caspase-1 into its active subunits. The activated caspase-1 proteolytically processes interleukin-1β (IL-1β) and interleukin-18 (IL-18) into maturation whilst co-ordinately triggers caspase-6 which is responsible for apoptosis and axonal degeneration. In addition, caspase-1 activation induces pyroptosis, an inflammatory form of programmed cell death. Studies in murine AD models indicate that the Nlrp1 inflammasome is indeed upregulated in AD and neuronal death is observed leading to cognitive decline. However, the mechanism of NLRP1 inflammasome activation in AD is particularly elusive, given its structural and functional complexities. In this review, we examine the implications of the human NLRP1 inflammasome and its signalling pathways in driving neuroinflammation in AD.
  9. Chan EWL, Yeo ETY, Wong KWL, See ML, Wong KY, Gan SY
    Curr Alzheimer Res, 2019;16(3):251-260.
    PMID: 30819080 DOI: 10.2174/1567205016666190228124630
    BACKGROUND: Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder that eventually leads to severe cognitive impairment. Although the exact etiologies of AD still remain elusive, increasing evidence suggests that neuroinflammation cascades mediated by microglial cells are associated with AD. Piper sarmentosum Roxb. (PS) is a medicinal plant reported to possess various biological properties, including anti-inflammatory, anti-psychotic and anti-oxidant activity. However, little is known about the anti-inflammatory activity of PS roots despite their traditional use to treat inflammatory- mediated ailments.

    OBJECTIVE: This study aimed to evaluate the anti-inflammatory and neuroprotective properties of extracts obtained from the roots of PS against beta-amyloid (Aβ)-induced microglial toxicity associated with the production of pro-inflammatory mediators.

    METHOD: BV2 microglial cells were treated with hexane (RHXN), dichloromethane (RDCM), ethyl acetate (REA) and methanol (RMEOH) extracts of the roots of PS prior to activation by Aβ. The production and mRNA expression of pro-inflammatory mediators were evaluated by Griess reagent, ELISA kits and RT-qPCR respectively. The phosphorylation status of p38α MAPK was determined via western blot assay. BV2 conditioned medium was used to treat SH-SY5Y neuroblastoma cells and the neuroprotective effect was assessed using MTT assay.

    RESULTS: PS root extracts, in particular RMEOH significantly attenuated the production and mRNA expression of IL-1β, IL-6 and TNF-α in Aβ-induced BV2 microglial cells. In addition, RHXN, REA and RMEOH extracts significantly reduced nitric oxide (NO) level and the inhibition of NO production was correlated with the total phenolic content of the extracts. Further mechanistic studies suggested that PS root extracts attenuated the production of cytokines by regulating the phosphorylation of p38α MAPK in microglia. Importantly, PS root extracts have protective effects against Aβ-induced indirect neurotoxicity either by inhibiting the production of NO, IL-1β, IL-6, and TNF-α in BV2 cells or by protecting SHSY5Y cells against these inflammatory mediators.

    CONCLUSIONS: These findings provided evidence that PS root extracts confer neuroprotection against Aβ- induced microglial toxicity associated with the production of pro-inflammatory mediators and may be a potential therapeutic agent for inflammation-related neurological conditions including Alzheimer's disease (AD).

  10. Md S, Gan SY, Haw YH, Ho CL, Wong S, Choudhury H
    Int J Biol Macromol, 2018 Oct 15;118(Pt A):1211-1219.
    PMID: 30001606 DOI: 10.1016/j.ijbiomac.2018.06.190
    Alzheimer's disease (AD) is an increasingly prevalent neurological disorder of the central nervous system. There is growing evidence that amyloidogenesis is a pathological hallmark for AD; this leads to the formation of senile plaques. Naringenin is a bioflavonoid which has neuroprotective effects through its antioxidant and anti-inflammatory properties. However, its clinical usage is limited due to its inefficient transport across biological membranes. In the present study, a naringenin nanoemulsion was prepared and its neuroprotective effects were tested against β-amyloid induced neurotoxicity in a human neuroblastoma cell line (SH-SY5Y). The optimised, naringenin-loaded nanoemulsion formulation had a droplet size of 113.83 ± 3.35 nm and around 50 nm, as assessed respectively by photon correlation spectroscopy and transmission electron microscopy. The preparation showed a low polydispersity index (0.312 ± 0.003), a high zeta potential (12.4 ± 1.05) and a high percentage transmittance (97.01%). The neuroprotective activity of naringenin nanoemulsions was determined by assessing their ability to protect SH-SY5Y neuroblastoma cells against the neurotoxic effect of beta amyloid (Aβ). Aβ-induced production of reactive oxygen species (ROS), amyloid precursor protein (APP), β-secretase (BACE), total tau and phosphorylated tau (pT231) was also determined. The naringenin loaded nanoemulsion significantly alleviated the direct neurotoxic effects of Aβ on SH-SY5Y cells; this was associated with a down-regulation of APP and BACE expression, indicating reduced amyloidogenesis. Furthermore, it decreased the levels of phosphorylated tau in SH-SY5Y cells exposed to Aβ. These results suggest that a naringenin-loaded nanoemulsion could be a promising agent for the treatment of Alzheimer's disease.
  11. Lim CK, Gan SY, Yi V, Jong M, Leong CO, Mai CW, et al.
    Pak J Pharm Sci, 2019 Sep;32(5):2183-2187.
    PMID: 31813886
    Phytochemical investigation on the dichloromethane stem bark extract of Calophyllum castaneum resulted in the isolation of five compounds, namely isoblancoic acid (1), blancoic acid (2), euxanthone (3), friedelin (4) and friedelinol (5). All these compounds were isolated for the first time from this plant. Their chemical structures were elucidated based on the spectroscopic analyses. The cytotoxicity of compounds 1-5 was assessed on a panel of cancer cell lines including bone (Saos-2, mg63), colorectal (HT29, Caco-2, HCC2998, SW48, HCT116, KM12), liver (HepG2), lung (H1299, Calu-3), and brain (C6), using 5-fluorouracil as positive control. Pronounced antiproliferative activities were observed for compound 1 which exhibited a comparable activity with the positive control, against brain (C6) and colorectal (SW48, KM12, HCT116) cancer cell lines showing IC50 values in the range of 14 to 65μM. Meanwhile, compound 5 displayed a greater cytotoxic effect showing at least 2-fold more strongly than the positive control, against C6 brain cancer cells. The assay findings have unveiled the therapeutic value of phytochemicals from Calophyllum castaneum as anti-cancer agents.
  12. Yeo ETY, Wong KWL, See ML, Wong KY, Gan SY, Chan EWL
    J Ethnopharmacol, 2018 May 10;217:187-194.
    PMID: 29462698 DOI: 10.1016/j.jep.2018.02.025
    ETHNOPHARMACOLOGICAL RELEVANCE: Piper sarmentosum Roxb. (PS), belonging to Piperaceae family, is an edible plant with medicinal properties. It is traditionally used by the Malays to treat headache and boost memory. Pharmacological studies revealed that PS exhibits anti-inflammatory, anti-oxidant, anti-acetylcholinesterase, and anti-depressant-like effects. In view of this, the present study aimed to investigate the anti-inflammatory actions of PS and its potential neuroprotective effects against beta-amyloid (Aβ)-induced microglia-mediated neurotoxicity.

    MATERIALS AND METHODS: The inhibitory effects of hexane (LHXN), dichloromethane (LDCM), ethyl acetate (LEA) and methanol (LMEOH) extracts from leaves of PS on Aβ-induced production and mRNA expression of pro-inflammatory mediators in BV-2 microglial cells were assessed using colorimetric assay with Griess reagent, ELISA kit and real-time RT-PCR respectively. Subsequently, MTT reduction assay was used to evaluate the neuroprotective effects of PS leaf extracts against Aβ-induced microglia-mediated neurotoxicity in SH-SY5Y neuroblastoma cells. The levels of tau proteins phosphorylated at threonine 231 (pT231) and total tau proteins (T-tau) were determined using ELISA kits.

    RESULTS: Polar extracts of PS leaves (LEA and LMEOH) reduced the Aβ-induced secretion of pro-inflammatory cytokines (IL-1β and TNF-α) in BV-2 cells by downregulating the mRNA expressions of pro-inflammatory cytokines. The inhibition of nitric oxide (NO) production could be due to the free radical scavenging activity of the extracts. In addition, conditioned media from Aβ-induced BV-2 cells pre-treated with LEA and LMEOH protected SH-SY5Y cells against microglia-mediated neurotoxicity. Further mechanistic study suggested that the neuroprotective effects were associated with the downregulation of phosphorylated tau proteins.

    CONCLUSIONS: The present study suggests that polar extracts of PS leaves confer neuroprotection against Aβ-induced microglia-mediated neurotoxicity in SH-SY5Y cells by attenuating tau hyperphosphorylation through their anti-inflammatory actions and could be a potential therapeutic agent for Alzheimer's disease.

  13. Sagap I, Loo GH, Azman ZAM, Mazlan L, Gan SY, Eng HS, et al.
    Br J Nurs, 2022 Dec 15;31(22):S34-S42.
    PMID: 36519479 DOI: 10.12968/bjon.2022.31.22.S34
    BACKGROUND: Choice of ostomy appliances is based on multiple factors including economic considerations, individual patient requirements and lifestyle. A recently launched two-piece ostomy collection device with an extended tape border is expected to provide a long wear time and increase patients' sense of security.

    AIMS AND METHODS: A randomised controlled, non-blinded, cross-over study involving 38 patients (with colostomies and ileostomies) compared the test device to a similar device from the same manufacturer but without the tape border. The main objective was to assess wear time for non-inferiority as a measure of efficacy. Secondary efficacy assessment included peristomal skin condition using the DET (discolouration, erosion and tissue growth) score and patient acceptability, which was assessed through questionnaires using Likert-scale options. Safety was assessed according to the incidence and intensity of device-related adverse events, and the condition of the peristomal skin.

    RESULTS AND CONCLUSION: Analysis of results in the per-protocol population showed an average wear time of 4.5 days for both devices and demonstrated non-inferiority. DET scores were similar in both groups, and both had low rates of device-related adverse events, all of which related to peristomal skin. Patients said the devices were user friendly. While the two devices are similar, some patients may find one with an adhesive tape more suited to their needs.

  14. Teh KJ, Tang HY, Lim LS, Pung HS, Gan SY, Lai NS
    Eur Rev Med Pharmacol Sci, 2023 May;27(10):4378-4385.
    PMID: 37259718 DOI: 10.26355/eurrev_202305_32443
    Lyme borreliosis is caused by the Gram-negative spirochetes Borrelia spp., particularly Borrelia burgdorferi sensu lato complex. The disease is transmitted through the bite of the infected black-legged Ixodes tick. Lyme borreliosis extensively occurs in the Northern Hemisphere, mainly in the United States. Lyme borreliosis cases are also detected in Asian countries including Korea, Nepal, China, Taiwan, and Japan. However, there is an inadequate understanding of Lyme borreliosis in the Southeast Asian region. Hence, this review aims to provide a brief update on the prevalence of Lyme borreliosis infection in Southeast Asia based on the latest literature on this issue. Lyme borreliosis has been discovered in human serum in Indonesia, Malaysia, and Singapore. The human serum samples were mainly examined with ELISA test using Borrelia spp. IgG and IgM antigens. Borrelia spp. also has been detected in ticks found on host animals such as Sundamys muelleri and Python in Malaysia, Thailand, and Laos. Polymerase chain reaction (PCR) is used to detect the presence of Borrelia DNAs in the samples. The published studies have demonstrated that Borrelia spp. exists in Southeast Asia and although the incidence is relatively low, it is believed that Lyme disease cases are under-reported.
  15. Sivam HGP, Chin BY, Gan SY, Ng JH, Gwenhure A, Chan EWL
    Cancer Biol Ther, 2023 Dec 31;24(1):2284857.
    PMID: 38018872 DOI: 10.1080/15384047.2023.2284857
    Modified macrophages, tumor-associated macrophages (TAMs), are key contributors to the survival, growth, and metastatic behavior of pancreatic ductal adenocarcinoma (PDAC) cells. Central to the role of inflammation and TAMs lies the NLRP3 inflammasome. This study investigated the effects of LPS-stimulated inflammation on cell proliferation, levels of pro-inflammatory cytokines, and the NLRP3 inflammasome pathway in a co-culture model using PDAC cells and macrophages in the presence or absence of MCC950, a NLRP3-specific inhibitor. The effects of LPS-stimulated inflammation were tested on two PDAC cell lines (Panc 10.05 and SW 1990) co-cultured with RAW 264.7 macrophages. Cell proliferation was determined using the MTT assay. Levels of pro-inflammatory cytokines, IL-1β, and TNF-α were determined by ELISA. Western blot analyses were used to examine the expression of NLRP3 in both PDAC cells and macrophages. The co-culture and interaction between PDAC cell lines and macrophages led to pro-inflammatory microenvironment under LPS stimulation as evidenced by high levels of secreted IL-1β and TNF-α. Inhibition of the NLRP3 inflammasome by MCC950 counteracted the effects of LPS stimulation on the regulation of the NLRP3 inflammasome and pro-inflammatory cytokines in PDAC and macrophages. However, MCC950 differentially modified the viability of the metastatic vs primary PDAC cell lines. LPS stimulation increased PDAC cell viability by regulating the NLRP3 inflammasome and pro-inflammatory cytokines in the tumor microenvironment of PDAC cells/macrophages co-cultures. The specific inhibition of the NLRP inflammasome by MCC950 effectively counteracted the LPS-stimulated inflammation.
  16. Cc Chow F, Chan SP, Hwu CM, Suwanwalaikorn S, Wu AY, Gan SY, et al.
    J Diabetes Investig, 2012 Dec 20;3(6):481-9.
    PMID: 24843611 DOI: 10.1111/jdi.12006
    It is well recognised that Asia is at the epicenter of the global type 2 diabetes epidemic. Driven by socioeconomic changes involving industrialization, urbanization and adoption of Western lifestyles, the unprecedented increases in the prevalence of diabetes are particularly evident in Southeast Asia. The impact of diabetes is immense, and despite evidence of the benefit of optimal glucose control in reducing the risk of disease progression and development of macrovascular and microvascular complications, many individuals in this region remain poorly controlled. Chronic kidney disease (CKD) is an increasingly common diabetes-associated complication in Asian patients. Furthermore, Southeast Asia has one of the highest rates of end-stage renal disease (ESRD) in the world. Consequently, CKD in diabetes is associated with considerable morbidity and cardiovascular-related mortality, highlighting the need to screen and assess patients early in the course of the disease. The management of type 2 diabetes patients with declining renal function represents a significant challenge. Many of the older antidiabetic agents, such as metformin and sulfonylureas, are limited in their utility in CKD as a result of contraindications or hypoglycemic episodes. In contrast, dipeptidyl-peptidase IV inhibitors have provided a welcome addition to the therapeutic armamentarium for achieving glycemic control in these special populations. With comparable efficacy to and more favorable pharmacokinetic and side-effect profiles than traditional therapies, agents in this drug class, such as linagliptin, offer a more tailored approach to disease control in type 2 diabetes patients with declining renal function.
  17. Chan EWL, Yeo ETY, Wong KWL, See ML, Wong KY, Yap JKY, et al.
    Curr Alzheimer Res, 2021;18(1):80-87.
    PMID: 33761853 DOI: 10.2174/1567205018666210324124239
    BACKGROUND: In Alzheimer's disease, accumulation of beta amyloid (Aβ) triggers amyloidogenesis and hyperphosphorylation of tau protein leading to neuronal cell death. Piper sarmentosum Roxb. (PS) is a traditional medicinal herb used by Malay to treat rheumatism, headache and boost memory. It possesses various biological effects, such as anti-cholinergic, anti-inflammatory, anti-oxidant and anti-depressant-like effects.

    OBJECTIVE: The present study aimed to investigate neuroprotective properties of PS against Aβ-induced neurotoxicity and to evaluate its potential mechanism of action.

    METHODS: Neuroprotective effects of hexane (HXN), dichloromethane (DCM), ethyl acetate (EA) and methanol (MEOH) extracts from leaves (L) and roots (R) of PS against Aβ-induced neurotoxicity were investigated in SH-SY5Y human neuroblastoma cells. Cells were pre-treated with PS for 24 h followed by 24 h of induction with Aβ. The neuroprotective effects of PS were studied using cell viability and cellular reactive oxygen species (ROS) assays. The levels of extracellular Aβ and tau proteins phosphorylated at threonine 231 (pT231) were determined. Gene and protein expressions were assessed using qRT-PCR analyses and western blot analyses, respectively.

    RESULTS: Hexane extracts of PS (LHXN and RHXN) protected SH-SY5Y cells against Aβ-induced neurotoxicity, and decreased levels of extracellular Aβ and phosphorylated tau (pT231). Although extracts of PS inhibited Aβ-induced ROS production, it was unlikely that neuroprotective effects were simply due to the anti-oxidant capacity of PS. Further, mechanistic study suggested that the neuroprotective effects of PS might be due to its capability to regulate amyloidogenesis through the downregulation of BACE and APP.

    CONCLUSION: These findings suggest that hexane extracts of PS confer neuroprotection against Aβ- induced neurotoxicity in SH-SY5Y cells by attenuating amyloidogenesis and tau hyperphosphorylation. Due to its neuroprotective properties, PS might be a potential therapeutic agent for Alzheimer's disease.

  18. Gan SY, Hairi FM, Danaee M, Amer Nordin AS, Quah ACK, Kaai SC, et al.
    PMID: 39192573 DOI: 10.1177/10105395241273250
    Smoke-free laws (SFL) are more effective with public support. This study investigated the smoking prevalence, public perceptions of smoking rules, and support for comprehensive SFL among 1047 people who smoke (PWS) and 206 people who do not smoke (PNS) aged ≥18 in the 2020 International Tobacco Control Malaysia Survey. Smoking prevalence was highest in nighttime entertainment venues (85.7%), non-air-conditioned eateries (49.7%), and indoor workplaces (34.6%). Respondents reported that smoking was banned in most indoor workplaces (81.7% PNS, 69.2% PWS), air-conditioned eateries (84.7% PNS, 75.7% PWS), and non-air-conditioned eateries (81.2% PNS, 78.7% PWS), but much less so in nighttime entertainment venues (30.1% PNS, 24.6% PWS). Support for comprehensive SFL in public venues was highest among PNS (≥84.9%) but still substantial among PWS (≥49.9%). PWS under 40, Malay, married, and aware of smoking rules supported SFL more. Robust SFL enforcement is essential in Malaysia to reduce secondhand smoke exposure in public places.
  19. Gan SY, Saedon NI, Sukanya S, Fairuz NHA, Sakinah SMN, Fatin NIAH, et al.
    Med J Malaysia, 2017 08;72(4):203-208.
    PMID: 28889130 MyJurnal
    No abstract available.
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