Displaying publications 1 - 20 of 28 in total

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  1. Fulltext A University-Wide Preparedness Effort in the Alert Phase of COVID-19 Incorporating Community Mental Health and Task-Shifting Strategies: Experience from a Bornean Institute of Higher Learning
    Mukhsam MH, Jeffree MS, Pang NTP, Syed Abdul Rahim SS, Omar A, Abdullah MS, et al.
    Am J Trop Med Hyg, 2020 Sep;103(3):1201-1203.
    PMID: 32705977 DOI: 10.4269/ajtmh.20-0458
    The COVID-19 pandemic caught the world by surprise, causing millions of confirmed cases and hundreds of thousands of deaths. Hence, the Malaysian government announced a Movement Control Order at the start of the containment phase to flatten the epidemiological curve. Universiti Malaysia Sabah (UMS), a public university in Borneo, was accelerated into alert phase because of high risk of case importation from more than 400 China incoming undergraduates. Measures to mitigate the potential COVID-19 outbreaks in its population were taken by using conventional public health measures with special attention to task-shifting and widespread community mental health interventions. A Preparedness and Response Centre was established to overseer the mitigating measures happening inside the university. Measures taken included empowerment of frontline staff, strengthening of restrictions, strengthening university health center, vigorous contact tracing, widespread health education, maintaining cultural sensitivity, and establishment of early standard operating procedures and university continuity plans. Hence, UMS was able to ensure no importation of cases into its campus during both acute and containment phases at the nationwide level.
  2. Fulltext Trapped cystofix: Laparoscopic modality to untie
    Muhamad A, Johan S, Khairuddin A, Hayati F, Payus AO, Zainal Abidin ZA
    Urol Case Rep, 2021 Jan;34:101448.
    PMID: 33088720 DOI: 10.1016/j.eucr.2020.101448
    Suprapubic catheterization (SPC) is a temporary measure to relieve acute urinary retention (AUR). Despite being effective, it can lead to complications such as colon perforation, haematuria, and bladder wall spasm. We present a 52-year-old lady with cystofix for underlying urethral stricture presented with AUR. A new SPC was inserted to drain the urine. However, the SPC had looped and entangled with her cystofix, and laparoscopic removal of cystofix and insertion of a new SPC was done. In conclusion, trapped cystofix to the SPC tube is a potential complication during SPC insertion that can be avoided with appropriate care.
  3. Solution structure and in silico binding of a cyclic peptide with hepatitis B surface antigen
    Muhamad A, Ho KL, Rahman MB, Uhrín D, Tan WS
    Chem Biol Drug Des, 2013 Jun;81(6):784-94.
    PMID: 23405984 DOI: 10.1111/cbdd.12120
    A specific ligand targeting the immunodominant region of hepatitis B virus is desired in neutralizing the infectivity of the virus. In a previous study, a disulfide constrained cyclic peptide cyclo S(1) ,S(9) Cys-Glu-Thr-Gly-Ala-Lys-Pro-His-Cys (S(1) , S(9) -cyclo-CETGAKPHC) was isolated from a phage displayed cyclic peptide library using an affinity selection method against hepatitis B surface antigen. The cyclic peptide binds tightly to hepatitis B surface antigen with a relative dissociation constant (KD (rel) ) of 2.9 nm. The binding site of the peptide was located at the immunodominant region on hepatitis B surface antigen. Consequently, this study was aimed to elucidate the structure of the cyclic peptide and its interaction with hepatitis B surface antigen in silico. The solution structure of this cyclic peptide was solved using (1) H, (13) C, and (15) N NMR spectroscopy and molecular dynamics simulations with NMR-derived distance and torsion angle restraints. The cyclic peptide adopted two distinct conformations due to the isomerization of the Pro residue with one structured region in the ETGA sequence. Docking studies of the peptide ensemble with a model structure of hepatitis B surface antigen revealed that the cyclic peptide can potentially be developed as a therapeutic drug that inhibits the virus-host interactions.
  4. Hepatitis B virus peptide inhibitors: solution structures and interactions with the viral capsid
    Muhamad A, Ho KL, Rahman MB, Tejo BA, Uhrín D, Tan WS
    Org Biomol Chem, 2015 Jul 28;13(28):7780-9.
    PMID: 26100394 DOI: 10.1039/c5ob00449g
    Hepatitis B virus (HBV) infection remains a health problem globally despite the availability of effective vaccines. In the assembly of the infectious virion, both the preS and S regions of the HBV large surface antigen (L-HBsAg) interact synergistically with the viral core antigen (HBcAg). Peptides preS and S based on the L-HBsAg were demonstrated as potential inhibitors to block the viral assembly. Therefore, the objectives of this study were to determine the solution structures of these peptides and study their interactions with HBcAg. The solution structures of these peptides were solved using (1)H, (13)C, and (15)N NMR spectroscopy. Peptide preS has several structured regions of β-turns at Ser7-Pro8-Pro9, Arg11-Thr12-Thr13 and Ser22-Thr23-Thr24 sequences whereas peptide S has only one structured region observed at Ser3-Asn4-His5. Both peptides contain bend-like structures surrounding the turn structures. Docking studies revealed that both peptides interacted with the immunodominant region of HBcAg located at the tip of the viral capsid spikes. Saturation Transfer Difference (STD) NMR experiments identified several aromatic residues in peptides preS and S that interact with HBcAg. This study provides insights into the contact regions of L-HBsAg and HBcAg at atomic resolution which can be used to design antiviral agents that inhibit HBV morphogenesis.
  5. A 12-residue epitope displayed on phage T7 reacts strongly with antibodies against foot-and-mouth disease virus
    Wong CL, Yong CY, Muhamad A, Syahir A, Omar AR, Sieo CC, et al.
    Appl Microbiol Biotechnol, 2018 May;102(9):4131-4142.
    PMID: 29564523 DOI: 10.1007/s00253-018-8921-9
    Foot-and-mouth disease (FMD) is a major threat to the livestock industry worldwide. Despite constant surveillance and effective vaccination, the perpetual mutations of the foot-and-mouth disease virus (FMDV) pose a huge challenge to FMD diagnosis. The immunodominant region of the FMDV VP1 protein (residues 131-170) displayed on phage T7 has been used to detect anti-FMDV in bovine sera. In the present study, the functional epitope was further delineated using amino acid sequence alignment, homology modelling and phage display. Two highly conserved regions (VP1145-152 and VP1159-170) were identified among different FMDV serotypes. The coding regions of these two epitopes were fused separately to the T7 genome and displayed on the phage particles. Interestingly, chimeric phage displaying the VP1159-170 epitope demonstrated a higher antigenicity than that displaying the VP1131-170 epitope. By contrast, phage T7 displaying the VP1145-152 epitope did not react significantly with the anti-FMDV antibodies in vaccinated bovine sera. This study has successfully identified a smaller functional epitope, VP1159-170, located at the C-terminal end of the structural VP1 protein. The phage T7 displaying this shorter epitope is a promising diagnostic reagent to detect anti-FMDV antibodies in vaccinated animals.
  6. Perturbations in Amino Acid Metabolism in Reserpine-Treated Zebrafish Brain Detected by 1H Nuclear Magnetic Resonance-Based Metabolomics
    Zakaria F, Akhtar MT, Wan Ibrahim WN, Abu Bakar N, Muhamad A, Shohaimi S, et al.
    Zebrafish, 2021 02;18(1):42-54.
    PMID: 33538644 DOI: 10.1089/zeb.2020.1895
    Depression is a complex and disabling psychiatric disorder, which is expected to be a leading cause for disability by 2030. According to World Health Organization, about 350 million people are suffering with mental health disorders around the globe, especially depression. However, the mechanisms involved in stress-induced depression have not been fully elucidated. In this study, a stress-like state was pharmacologically induced in zebrafish using reserpine, a drug widely used to mediate depression in experimental animal models. Zebrafish received single intraperitoneal (i.p.) injections of 20, 40, and 80 mg/kg body weight reserpine doses and were subjected to open-field test at 2, 24, 48, 72, and 96 h after the treatment. Along with observed changes in behavior and measurement of cortisol levels, the fish were further examined for perturbations in their brain metabolites by 1H nuclear magnetic resonance (NMR)-based metabolomics. We found a significant increase in freezing duration, whereas total distance travelled was decreased 24 h after single intraperitoneal injection of reserpine. Cortisol level was also found to be higher after 48 h of reserpine treatment. The 1H NMR data showed that the levels of metabolites such as glutamate, glutamine, histamine, valine, leucine and histidine, lactate, l-fucose, betaine and γ-amino butyric acid (GABA), β-hydroxyisovalerate, and glutathione were significantly decreased in the reserpine-treated group. This study provided some insights into the molecular nature of stress that could contribute toward a better understanding of depression disorder.
  7. Centella asiatica (L.) Urb. Extract ameliorates branched-chain amino acid (BCAA) metabolism in acute reserpine-induced stress zebrafish model via 1H Nuclear Magnetic Resonance (NMR)-based metabolomics approach
    Zakaria F, Akhtar MT, Wan Norhamidah WI, Noraini AB, Muhamad A, Shohaimi S, et al.
    Comp Biochem Physiol C Toxicol Pharmacol, 2023 Feb;264:109501.
    PMID: 36336330 DOI: 10.1016/j.cbpc.2022.109501
    Depression is a common mental disorder that can adversely affect psychosocial function and quality of life. However, the exact aetiology and pathogenesis of depression are still unclear. Stress plays a major role in the pathogenesis of depression. The use of currently prescribed antidepressants has many side effects. Centella asiatica (C. asiatica) has shown promising antidepressant activity in rodent models. Here, we developed a reserpine-induced zebrafish stress-like model and performed behavioural analysis, cortisol measurement and 1H-Nuclear Magnetic Resonance (1H NMR) spectroscopy-based metabolomics analysis to test the anti-stress activity of ethanolic extract of C. asiatica (RECA). A significant increase in total distance travelled (F(8,8) = 8.905, p = 0.0054) and a reduction in freezing duration (F(9, 9) = 10.38, p = 0.0018) were found in the open field test (OFT). Asiaticoside, one of tested C.asiatica's triterpenoid gives a significant increase in contact duration (F(5,5) = 142.3, (p = 0.0330) at 2.5 mg/kg). Eight biomarkers were found, i.e. ß-hydroxyisovaleric acid, leucine, threonine, scylloinositol, lactate, betaine, valine, choline and l-fucose, to be responsible for the class separation between stress and RECA-treated groups. Metabolic pathway alteration in zebrafish brain upon treatment with RECA was identified as valine, leucine and isoleucine biosynthesis, while alanine, aspartate, glutamate and glycerophospholipid metabolism was involved after fluoxetine treatment.
  8. Fulltext Meat Quality, Fatty Acid Content and NMR Metabolic Profile of Dorper Sheep Supplemented with Bypass Fats
    Behan AA, Akhtar MT, Loh TC, Fakurazi S, Kaka U, Muhamad A, et al.
    Foods, 2021 May 19;10(5).
    PMID: 34069633 DOI: 10.3390/foods10051133
    The supplementation of rumen bypass fat (RBF) has remained one of the preferred approaches used to decrease undesirable saturated fatty acids (FA) and increase beneficial unsaturated FA in the meat. This study was planned to evaluate the influences of rumen bypass fats on meat quality, fatty acid and metabolic profiles in male Dorper sheep (n = 36) with 24.66 ± 0.76 kg (mean ± standard error) initial body weight. Treatment comprised a basal diet (30:70 rice straw to concentrate) with no added RBF as a control (CON), basal diet with prilled fat (PF), basal diet with prilled fat plus lecithin (PFL) and basal diet with calcium soap of palm fatty acids (CaS). The findings revealed that cooking loss, drip loss and shear force in longissimus dorsi (LD) muscle were not affected by RBF supplementation, while meat pH was significantly higher in the CaS on aging day 1. However, the diet supplemented with prilled fat and lecithin modified the meat's fatty acid profile significantly by increasing unsaturated fatty acids and decreasing saturated fats. The relative quantification of the major differentiating metabolites found in LD muscle of sheep showed that total cholesterol, esterified cholesterol, choline, glycerophosphocholine and glycerophospholipids were significantly lower in CaS and PFL diets, while glycerol and sphingomyelin were significantly higher in CaS and PFL diets. Most of the metabolites in the liver did not show any significant difference. Based on our results, the supplementation of protected fats did not have a negative influence on meat quality and the meat from Dorper sheep fed prilled fat with lecithin contained more healthy fatty acids compared to other diets.
  9. Generation mean analysis of grain quality traits in selected rice populations derived from different amylose characteristics
    Ramli AB, Rafii MY, Latif MA, Saleh GB, Omar OB, Puteh AB
    J Sci Food Agric, 2016 Mar;96(5):1593-600.
    PMID: 25982124 DOI: 10.1002/jsfa.7260
    Genetic analysis using generation mean analysis is a tool for designing the most appropriate breeding approaches to developing varieties of rice. It estimates the gene actions that control quantitative traits, as well as the additive, dominance and epistatic effects. This study was conducted using three rice populations that were derived from parental lines with different amylose content. The aim was to partition the gene actions using generation mean analysis for the selected populations.
  10. Fulltext Gastric trichobezoar in an end-stage renal failure and mental health disorder presented with chronic epigastric pain: A case report
    Ali AA, Gurung R, Fuad ZM, Moosa M, Ali I, Abdulla A, et al.
    Ann Med Surg (Lond), 2020 Oct;58:76-79.
    PMID: 32953103 DOI: 10.1016/j.amsu.2020.08.021
    Background: Gastric trichobezoar happens when there is an indigestible substance or food found in the gastrointestinal tract. It is a rare presentation which is usually associated with trichotillomania and trichopagia. The presentation may not be specific and is usually related to dyspepsia-like symptoms. In the worst-case scenario, this may cause gastric outlet or intestinal obstruction which eventually requires surgery.

    Case presentation: We present a 36-year-old lady with underlying end-stage renal failure (ESRF) and undiagnosed mental health issues who was treated for recurrent episodes of gastritis. Imaging modalities revealed intragastric foreign body ingestion which is consistent with gastric trichobezoar. She eventually underwent laparotomy and gastrotomy to remove the foreign body. Postoperatively, she was referred and followed-up by the psychiatric team.

    Conclusion: Gastric trichobezoar has strong associations with psychiatric disorders. With the co-existence of an ESRF, uraemia might contribute to the aetiology of the trichotillomania and trichophagia. Open surgery is the choice of definitive management especially if bezoars are larger. Should the recurrence be remitted, a biopsychosocial modality and regular haemodialysis is the most sustainable approach to ensure the behaviour does not persist.

  11. Peptidyl-prolyl isomerases: functionality and potential therapeutic targets in cardiovascular disease
    Rostam MA, Piva TJ, Rezaei HB, Kamato D, Little PJ, Zheng W, et al.
    Clin Exp Pharmacol Physiol, 2015 Feb;42(2):117-24.
    PMID: 25377120 DOI: 10.1111/1440-1681.12335
    Peptidyl-prolyl cis/trans isomerases (PPIases) are a conserved group of enzymes that catalyse the conversion between cis and trans conformations of proline imidic peptide bonds. These enzymes play critical roles in regulatory mechanisms of cellular function and pathophysiology of disease. There are three different classes of PPIases and increasing interest in the development of specific PPIase inhibitors. Cyclosporine A, FK506, rapamycin and juglone are known PPIase inhibitors. Herein, we review recent advances in elucidating the role and regulation of the PPIase family in vascular disease. We focus on peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (Pin1), an important member of the PPIase family that plays a role in cell cycle progression, gene expression, cell signalling and cell proliferation. In addition, Pin1 may be involved in atherosclerosis. The unique role of Pin1 as a molecular switch that impacts on multiple downstream pathways necessitates the evaluation of a highly specific Pin1 inhibitor to aid in potential therapeutic drug discovery.
  12. The role of specific Smad linker region phosphorylation in TGF-β mediated expression of glycosaminoglycan synthesizing enzymes in vascular smooth muscle
    Rostam MA, Kamato D, Piva TJ, Zheng W, Little PJ, Osman N
    Cell Signal, 2016 08;28(8):956-66.
    PMID: 27153775 DOI: 10.1016/j.cellsig.2016.05.002
    Hyperelongation of glycosaminoglycan chains on proteoglycans facilitates increased lipoprotein binding in the blood vessel wall and the development of atherosclerosis. Increased mRNA expression of glycosaminoglycan chain synthesizing enzymes in vivo is associated with the development of atherosclerosis. In human vascular smooth muscle, transforming growth factor-β (TGF-β) regulates glycosaminoglycan chain hyperelongation via ERK and p38 as well as Smad2 linker region (Smad2L) phosphorylation. In this study, we identified the involvement of TGF-β receptor, intracellular serine/threonine kinases and specific residues on transcription factor Smad2L that regulate glycosaminoglycan synthesizing enzymes. Of six glycosaminoglycan synthesizing enzymes, xylosyltransferase-1, chondroitin sulfate synthase-1, and chondroitin sulfotransferase-1 were regulated by TGF-β. In addition ERK, p38, PI3K and CDK were found to differentially regulate mRNA expression of each enzyme. Four individual residues in the TGF-β receptor mediator Smad2L can be phosphorylated by these kinases and in turn regulate the synthesis and activity of glycosaminoglycan synthesizing enzymes. Smad2L Thr220 was phosphorylated by CDKs and Smad2L Ser250 by ERK. p38 selectively signalled via Smad2L Ser245. Phosphorylation of Smad2L serine residues induced glycosaminoglycan synthesizing enzymes associated with glycosaminoglycan chain elongation. Phosphorylation of Smad2L Thr220 was associated with XT-1 enzyme regulation, a critical enzyme in chain initiation. These findings provide a deeper understanding of the complex signalling pathways that contribute to glycosaminoglycan chain modification that could be targeted using pharmacological agents to inhibit the development of atherosclerosis.
  13. Fulltext Protean manifestations of gastrointestinal tuberculosis
    Ismail Y, Muhamad A
    Med J Malaysia, 2003 Aug;58(3):345-9.
    PMID: 14750373
    We present 11 cases to illustrate the protean presentations of gastrointestinal tuberculosis. The patients presented with perianal fistula, appendicitis, ascites, rectal, intestinal or gastric 'growth', "ulcerative colitis", or recurrent anemia. In some of these cases there was no conclusive proof of infection with Mycobacterium tuberculosis but they responded well to empirical treatment with anti-tuberculous therapy. These cases illustrate that because signs and symptoms of intestinal tuberculosis are non-specific and even histology can be misleading, the diagnosis of gastrointestinal tuberculosis requires a high index of suspicion. A therapeutic trial of antituberculous drugs should be considered for patients with a high clinical suspicion of tuberculosis.
  14. Prayer Moderating Job Stress Among Muslim Nursing Staff at the University of Malaya Medical Centre (UMMC)
    Achour M, Muhamad A, Syihab AH, Mohd Nor MR, Mohd Yusoff MYZ
    J Relig Health, 2021 Feb;60(1):202-220.
    PMID: 31079348 DOI: 10.1007/s10943-019-00834-6
    This study examines how Salat (prayer) in Islam moderates the relationship between job stress and life satisfaction among Muslim nursing staff. The researchers sampled 335 nursing staff employed at the University of Malaya Medical Centre in Kuala Lumpur, Malaysia. Their ages ranged from 21 to 60 years. The findings indicate the job stress was associated negatively with life satisfaction; there is a strong positive and significant correlation, respectively, between Salat and life satisfaction and that Salat reduces stress and increases the life satisfaction of Muslim nurses. Thus, Salat has a moderating effect on job stress and life satisfaction of Muslim nurses.
  15. Flavopiridol Inhibits TGF-β-Stimulated Biglycan Synthesis by Blocking Linker Region Phosphorylation and Nuclear Translocation of Smad2
    Rostam MA, Shajimoon A, Kamato D, Mitra P, Piva TJ, Getachew R, et al.
    J. Pharmacol. Exp. Ther., 2018 04;365(1):156-164.
    PMID: 29438988 DOI: 10.1124/jpet.117.244483
    Transforming growth factor-β (TGF-β) is a pleiotropic growth factor implicated in the development of atherosclerosis for its role in mediating glycosaminoglycan (GAG) chain hyperelongation on the proteoglycan biglycan, a phenomenon that increases the binding of atherogenic lipoproteins in the vessel wall. Phosphorylation of the transcription factor Smad has emerged as a critical step in the signaling pathways that control the synthesis of biglycan, both the core protein and the GAG chains. We have used flavopiridol, a well-known cyclin-dependent kinase inhibitor, to study the role of linker region phosphorylation in the TGF-β-stimulated synthesis of biglycan. We used radiosulfate incorporation and SDS-PAGE to assess proteoglycan synthesis, real-time polymerase chain reaction to assess gene expression, and chromatin immunoprecipitation to assess the binding of Smads to the promoter region of GAG Synthesizing genes. Flavopiridol blocked TGF-β-stimulated synthesis of mRNA for the GAG synthesizing enzymes, and chondroitin 4-sulfotransferase (C4ST-1), chondroitin sulfate synthase-1 (ChSy-1) and TGF-β-mediated proteoglycans synthesis as well as GAG hyperelongation. Flavopiridol blocked TGF-β-stimulated Smad2 phosphorylation at both the serine triplet and the isolated threonine residue in the linker region. The binding of Smad to the promoter region of the C4ST-1 and ChSy-1 genes was stimulated by TGF-β, and this response was blocked by flavopiridol, demonstrating that linker region phosphorylated Smad can pass to the nucleus and positively regulate transcription. These results demonstrate the validity of the kinases, which phosphorylate the Smad linker region as potential therapeutic target(s) for the development of an agent to prevent atherosclerosis.
  16. Alstoscholactine and Alstolaxepine, Monoterpenoid Indole Alkaloids with γ-Lactone-Bridged Cycloheptane and Oxepane Moieties from Alstonia scholaris
    Krishnan P, Lee FK, Chong KW, Mai CW, Muhamad A, Lim SH, et al.
    Org. Lett., 2018 12 21;20(24):8014-8018.
    PMID: 30543301 DOI: 10.1021/acs.orglett.8b03592
    Two new monoterpenoid indole alkaloids, alstoscholactine (1) and alstolaxepine (2), were isolated from Alstonia scholaris. Compound 1 represents a rearranged stemmadenine alkaloid with an unprecedented C-6-C-19 connectivity, whereas compound 2 represents a 6,7- seco-angustilobine B-type alkaloid incorporating a rare γ-lactone-bridged oxepane ring system. Their structures and absolute configurations were determined by spectroscopic analyses. Compound 1 was successfully semisynthesized from 19 E-vallesamine. Compound 2 induced marked vasorelaxation in rat isolated aortic rings precontracted with phenylephrine.
  17. Concise synthesis of the vasorelaxant alkaloids schwarzinicines A and B
    Lee FK, Krishnan P, Muhamad A, Low YY, Kam TS, Ting KN, et al.
    Nat Prod Res, 2021 Mar 22.
    PMID: 33749454 DOI: 10.1080/14786419.2021.1903005
    A concise synthesis of the 1,4-diarylbutanoid-phenethylamine alkaloids, schwarzinicines A (1) and B (2), recently isolated from Ficus schwarzii, is reported. Key steps include a Claisen condensation to assemble the 1,4-diaryl-2-butanone intermediate, followed by a reductive amination to furnish the core skeleton of the target compounds. The overall synthetic yields of 1 and 2 were 9.1% and 3.5%, respectively. Synthetic (-)-1, (+)-1 and (±)-1 exhibited comparable vasorelaxation as natural schwarzinicine A on rat isolated aortic rings, suggesting that the observed vasorelaxant effects were not influenced by the chirality at C-2.
  18. Preparation and Preliminary Structure-Activity Relationship Studies of Schwarzinicine A Analogs as Vasorelaxant Agents
    Lee FK, Chan NJ, Krishnan P, Datu Abdul Salam DS, Chee XW, Muhamad A, et al.
    J Nat Prod, 2024 Apr 26;87(4):675-691.
    PMID: 38442031 DOI: 10.1021/acs.jnatprod.3c00707
    Schwarzinicines A-D, a series of alkaloids recently discovered from Ficus schwarzii, exhibit pronounced vasorelaxant activity in rat isolated aorta. Building on this finding, a concise synthesis of schwarzinicines A and B has been reported, allowing further investigations into their biological properties. Herein, a preliminary exploration of the chemical space surrounding the structure of schwarzinicine A (1) was carried out aiming to identify structural features that are essential for vasorelaxant activity. A total of 57 analogs were synthesized and tested for vasorelaxant activity in rat isolated aorta. Both efficacy (Emax) and potency (EC50) of these analogs were compared. In addition to identifying structural features that are required for activity or associated with potency enhancement effect, four analogs showed significant potency improvements of up to 40.2-fold when compared to 1. Molecular dynamics simulation of a tetrameric 44-bound transient receptor potential canonical-6 (TRPC6) protein indicated that 44 could potentially form important interactions with the residues Glu509, Asp530, Lys748, Arg758, and Tyr521. These results may serve as a foundation for guiding further structural optimization of the schwarzinicine A scaffold, aiming to discover even more potent analogs.
  19. Identification of α-tocopherol as a bioactive component of Dicranopteris linearis with disrupting property against preformed biofilm of Staphylococcus aureus
    Mawang CI, Lim YY, Ong KS, Muhamad A, Lee SM
    J Appl Microbiol, 2017 Nov;123(5):1148-1159.
    PMID: 28869803 DOI: 10.1111/jam.13578
    AIMS: The potential of Dicranopteris linearis leaves' extract and its bioactive components were investigated for the first time for its disrupting ability against Staphylococcus aureus biofilms.

    METHODS AND RESULTS: The leaves of D. linearis were subjected to sonication-assisted extraction using hexane (HEX), dichloromethane, ethyl acetate and methanol (MeOH). It was found that only the MeOH fraction exhibited antimicrobial activity using broth microdilution assay; while all four fractions do not exhibit biofilm inhibition activity against S. aureusATCC 6538P, S. aureusATCC 43300, S. aureusATCC 33591 and S. aureusATCC 29213 using crystal violet assay. Among the four fractions tested, only the HEX fraction showed biofilm disrupting ability, with 60-90% disruption activity at 5 mg ml-1against all four S. aureus strains tested. Bioassay-guided purification of the active fraction has led to the isolation of α-tocopherol. α-Tocopherol does not affect the cells within the biofilms but instead affects the biofilm matrix in order to disrupt S. aureus biofilms.

    CONCLUSIONS: α-Tocopherol was identified to be the bioactive component of D. linearis with disruption activity against S. aureus biofilm matrix.

    SIGNIFICANCE AND IMPACT OF THE STUDY: The use of α-tocopherol as a biofilm disruptive agent might potentially be useful to treat biofilm-associated infections in the future.

  20. Fulltext Investigation on the antimicrobial activities of gingers (Etlingera coccinea (Blume) S.Sakai & Nagam and Etlingera sessilanthera R.M.Sm.) endemic to Borneo
    Daniel-Jambun D, Dwiyanto J, Lim YY, Tan JBL, Muhamad A, Yap SW, et al.
    J Appl Microbiol, 2017 Oct;123(4):810-818.
    PMID: 28708293 DOI: 10.1111/jam.13536
    AIMS: To investigate the antimicrobial properties of Etlingera coccinea and Etlingera sessilanthera and to isolate and identify the antimicrobial compounds.

    METHODS AND RESULTS: Extracts were obtained via sequential solvent extraction method using hexane, dichloromethane, ethyl acetate, methanol and water. Antimicrobial activity testing was done using broth microdilution assay against 17 strains of bacteria. The leaf hexane extract of E. coccinea and rhizome hexane extract of E. sessilanthera showed best antimicrobial activities, with minimum inhibitory concentration (MIC) values ranging from 0·016 to 1 mg ml-1 against Gram-positive bacteria. From these active extracts, two antimicrobials were isolated and identified as trans-2-dodecenal and 8(17),12-labdadiene-15,16-dial with MIC values ranging from 4 to 8 μg ml-1 against Bacillus cereus, Bacillus subtilis and Staphylococcus aureus.

    CONCLUSION: Etlingera coccinea and E. sessilanthera demonstrated good antimicrobial activities against clinically relevant bacteria strains. The antimicrobial compounds isolated showed low MIC values, hence suggesting their potential use as antimicrobial agents.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to identify the potent antimicrobials from these gingers. The antimicrobials isolated could potentially be developed further for use in treatment of bacterial infections. Also, this study warrants further research into other Etlingera species in search for more antimicrobial compounds.

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