Displaying publications 421 - 440 of 680 in total

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  1. Fulltext Cytotoxic and anticancer properties of the Malaysian mangrove pit viper (Trimeresurus purpureomaculatus) venom and its disintegrin (purpureomaculin)
    Tan CH, Liew JL, Navanesan S, Sim KS, Tan NH, Tan KY
    J Venom Anim Toxins Incl Trop Dis, 2020;26:e20200013.
    PMID: 32742279 DOI: 10.1590/1678-9199-JVATITD-2020-0013
    Background: The Asiatic pit vipers from the Trimeresurus complex are medically important venomous snakes. These pit vipers are often associated with snakebite that leads to fatal coagulopathy and tissue necrosis. The cytotoxic venoms of Trimeresurus spp.; however, hold great potential for the development of peptide-based anticancer drugs.

    Methods: This study investigated the cytotoxic effect of the venom from Trimeresurus purpureomaculatus, the mangrove pit viper (also known as shore pit viper) which is native in Malaysia, across a panel of human cancer cell lines from breast, lung, colon and prostate as well as the corresponding normal cell lines of each tissue.

    Results: The venom exhibited dose-dependent cytotoxic activities on all cell lines tested, with median inhibition concentrations (IC50) ranging from 0.42 to 6.98 µg/mL. The venom has a high selectivity index (SI = 14.54) on breast cancer cell line (MCF7), indicating that it is significantly more cytotoxic toward the cancer than to normal cell lines. Furthermore, the venom was fractionated using C18 reversed-phase high-performance liquid chromatography and the anticancer effect of each protein fraction was examined. Fraction 1 that contains a hydrophilic low molecular weight (approximately 7.5 kDa) protein was found to be the most cytotoxic and selective toward the breast cancer cell line (MCF7). The protein was identified using liquid chromatography-tandem mass spectrometry as a venom disintegrin, termed purpureomaculin in this study.

    Conclusion: Taken together, the findings revealed the potent and selective cytotoxicity of a disintegrin protein isolated from the Malaysian T. purpureomaculatus venom and suggested its anticancer potential in drug discovery.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  2. The structural characterization and antioxidant properties of oil palm fronds lignin incorporated with p-hydroxyacetophenone
    Latif NHA, Rahim AA, Brosse N, Hussin MH
    Int J Biol Macromol, 2019 Jun 01;130:947-957.
    PMID: 30851323 DOI: 10.1016/j.ijbiomac.2019.03.032
    This study reports on the effects of unmodified autohydrolyzed ethanol organosolv lignin (AH EOL) and modified autohydrolyzed ethanol organosolv lignin on the structural characteristics and antioxidant properties upon incorporation of p-hydroxyacetophenone (AHP EOL). The lignin samples isolated from black liquor of oil palm fronds (OPF) were evaluated and compared using various complementary analyses; FTIR, 1H and 13C NMR spectroscopy, 2D-NMR spectroscopy (HMBC and HSQC), CHN, GPC, HPLC and thermal analyses (TGA and DSC). Chemically modified organosolv lignin (AHP EOL) provided lignin with lower molecular weight (Mw), which has smaller fragments that leads to higher solubility rate in water in comparison to unmodified organosolv lignin, AH EOL (DAHP EOL: 19.8% > DAH EOL: 14.0%). It was evident that the antioxidant properties of modified organosolv lignin has better reducing power in comparison to the unmodified organosolv lignin. Therefore, the functionalization of lignin polymers enhanced their antioxidant properties and structural features towards a various alternative approach in lignin-based applications.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  3. Hylocereus polyrhizus peel's high-methoxyl pectin: A potential source of hypolipidemic agent
    Zaid RM, Mishra P, Wahid ZA, Sakinah AMM
    Int J Biol Macromol, 2019 Aug 01;134:361-367.
    PMID: 31059740 DOI: 10.1016/j.ijbiomac.2019.03.143
    In the present study, high-methoxyl pectin (HMP) was extracted from Hylocereus polyrhizus peel's using physico-chemical process. In addition, the hypolipidemic activity of HMP was investigated at different concentration and time corresponding to its adsorption ability. FTIR and contact angle analysis were used to determine the sorbent characterization. A high degree of esterification (63.8%) and the contact angle (95.5°) confirmed hydrophobic nature and resulting bad wetting of the HMP extract, respectively. The methoxyl content in the pectin acted as an affinity-precursor of the pectin towards cholesterol due to its increased hydrophobicity. The maximum equilibrium uptake capacity of cholesterol of 370.5mg/g (0.96mmol/g) was observed by HMP. The experimental data showed good fitting for Freundlich isotherm equation and followed pseudo-first-order kinetic model with a correlation coefficient (R2) of 0.89-0.97 due to physisorption mechanism. Intra-particle model confirmed that the cholesterol sorption rate by HMP was significantly influenced by external mass transfer (surface diffusion) and intra-particle diffusion (diffusion control). It was also revealed that the HMP extracted from Hylocereus polyrhizus peels possess a high affinity towards cholesterol, making it an ideal hypolipidemic agent.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  4. Fulltext Pharmacokinetics of Free Oxytetracycline and Oxytetracycline Loaded Cockle Shell Calcium Carbonate-Based Nanoparticle in BALB/c Mice
    Idris SB, Abdul Kadir A, Abdullah JFF, Ramanoon SZ, Basit MA, Abubakar MZZA
    Front Vet Sci, 2020;7:270.
    PMID: 32613011 DOI: 10.3389/fvets.2020.00270
    The development and utilization of nano-antibiotics is currently gaining attention as a possible solution to antibiotic resistance. The aim of this study was therefore to determine the pharmacokinetics of free oxytetracycline (OTC) and oxytetracycline loaded cockle shell calcium carbonate-based nanoparticle (OTC-CNP) after a single dose of intraperitoneal (IP) administration in BALB/c mice. A total of 100 female BALB/c mice divided into two groups of equal number (n = 50) were administered with 10 mg/kg OTC and OTC-CNP, respectively. Blood samples were collected before and post-administration from both groups at time 0, 5, 10, 15, and 30 min and 1, 2, 6, 24, and 48 h, and OTC plasma concentration was quantified using a validated HPLC-UV method. The pharmacokinetic parameters were analyzed using a non-compartment model. The Cmax values of OTC in OTC-CNP and free OTC treated group were 64.99 and 23.53 μg/ml, respectively. OTC was detected up to 24 h in the OTC-CNP group as against 1 h in the free OTC group following intraperitoneal administration. In the OTC-CNP group, the plasma elimination rate of OTC was slower while the half-life, the area under the curve, and the volume of the distribution were increased. In conclusion, the pharmacokinetic profile of OTC in the OTC-CNP group differs significantly from that of free OTC. However, further studies are necessary to determine the antibacterial efficacy of OTC-CNP for the treatment of bacterial diseases.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  5. Fulltext Purification and characterization of charantin from Momordica charantia Linn.
    Oh, J. H., Lim, P. K., Hamzah, S., Tan, C. P., Chan, Sook Wah
    Malaysian Journal of Medicine and Health Sciences, 2019;15(102):43-43.
    MyJurnal
    Introduction: Diabetes mellitus (DM) is one of the top diseases that lead public health concern in Malaysia. It was believed to rise in number up to 4.5 million on cases by year 2020 based on the current figure. Momordica charantia Linn (MC), a climber belonging to family Cucurbitaceae, is well known in treating diabetic-related conditions. In earlier studies related to the hypoglycemic properties of MC mainly utilized the crude extract, which contain a mixture of bioactives (charantins, insulin-like peptides and alkaloids). Till now, there is no conclusive result on the major bioactives that play role in the hypoglycemic effect of MC and research regarding the charantin purification was not well established. Hence, the objectives of this study were to purify the charantin from MC and to characterize the purified charantin before further subjected to in vivo hypoglycemic study. Methods: The crude was first extracted from MC using ethanol as solvent via Soxhlet extraction following by a series of purification steps via washing, centrifugation, and C-18 cartridges. Results: The HPLC analysis showed that the charantin of purified extract after passing out from the cartridge exuded at 12.50 min with a concentration of 500 ppm, which is relatively 20 times higher than the crude extract (25 ppm). The structural properties of purified charantin were studied using FTIR and it showed strong peaks of carboxylic acids (2884 nm), alcohols (1023 nm) and diethyl ether (1114 nm) as compared
    with the standard. The compound was reconfirmed in LC-MS analysis. The result displayed mass spectrum in positive mode indicates the presence of similar compound in the purified extract and standard charantin, as presented by ion m/z = 300. Conclusion: The charantin was successfully purified from MC and can act as a potent plant-based hypoglycemic agent for diabetes.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  6. Understanding of the Role of Pretreatment Methods on Rapeseed Oil from the Perspective of Phenolic Compounds
    Xu YJ, Jiang F, Song J, Yang X, Shu N, Yuan L, et al.
    J Agric Food Chem, 2020 Aug 19;68(33):8847-8854.
    PMID: 32806128 DOI: 10.1021/acs.jafc.0c03539
    The thermal pretreatment of oilseed prior to oil extraction could increase the oil yield and improve the oil quality. Phenolic compounds are important antioxidants in rapeseed oil. In this study, we investigated the impact of thermal pretreatment method on the rapeseed oil based on phenolic compound levels. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis showed that the phenolic compound contents in the microwave-pretreated oil were higher than those in the oven- and infrared-treated oils. Sinapic acid (SA) and canolol (CA), which are the top two phenolic compounds in rapeseed oil, exerted well 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with IC50 values of 8.45 and 8.80 μmol/L. The cell experiment uncovered that SA and CA have significant biological activities related to rapeseed oil quality, including increase of antioxidant enzymes superoxide dismutase (SOD), alleviation of reactive oxygen species (ROS), and cytotoxicity of HepG2 cells after the intake of excessive oleic acid. Further investigation indicated that SA and CA reduced cell apoptosis rate through Bax-Bcl-2-caspase-3 and p53-Bax-Bcl-2-caspase-3, respectively. Taken together, our findings suggest that microwave pretreatment is the best method to improve the content of phenolic compounds in rapeseed oil compared with oven and infrared pretreatments.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  7. Anti-proliferative and anti-invasive properties of a purified fraction from Streptomyces sp. H7372
    Yip WK, Cheenpracha S, Chang LC, Ho CC, Seow HF
    Int J Oncol, 2010 Nov;37(5):1229-41.
    PMID: 20878070
    Secondary metabolites from actinomycetes especially the genus Streptomyces may be one of the most important sources for novel anticancer agents. A purified fraction from a novel actinomycete strain, Streptomyces sp. H7372, was elucidated in breast cancer cells. We have isolated three purified fractions from a novel strain, Streptomyces sp. H7372. One of the fractions, designated as 31-2, exhibited the strongest growth-inhibitory effect and thereby was selected for further studies. 31-2 exerted a growth-inhibitory effect on a panel of 15 human cancer and 2 non-malignant cell lines. In MCF-7 and MDA-MB-231 breast cancer cells, 31-2 induced a cytostatic (anti-proliferative) effect without causing cytotoxicity (cell death). Our data suggest that the cytostasis resulted from cell cycle arrest at the G1 phase in MCF-7 cells and at the S phase in MDA-MB-231 cells. Western blot analysis demonstrated a modulation of phosphorylation of the Rb and CDC2 proteins and of CDK4, cyclin D1 and cyclin D3 in the 31-2-treated breast cancer cell lines. The protein levels of CDK2, CDK6, and PCNA were not affected by 31-2 treatment. 31-2 also exhibited an anti-invasive effect in MDA-MB-231 cells. However, this effect is not attributed to the modulation of proteolytic activity in MDA-MB-231 cells as the enzymatic degradation of type IV collagen was not affected by 31-2. The 31-2 is a potent cytostatic and anti-invasive agent and modulates the cell cycle pathway. Together, these results will have important implications in searching for novel approaches to treat cancer.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  8. Immunomodulatory effects of Tinospora crispa extract and its major compounds on the immune functions of RAW 264.7 macrophages
    Ahmad W, Jantan I, Kumolosasi E, Haque MA, Bukhari SNA
    Int Immunopharmacol, 2018 Jul;60:141-151.
    PMID: 29730557 DOI: 10.1016/j.intimp.2018.04.046
    The in vivo immunomodulatory activities of Tinospora crispa have been reported but its molecular mechanisms underlying its immunomodulatory properties remains obscure and the active constituents contributing to the activities have not been identified. The present study was aimed to investigate the immunomodulatory effects of T. crispa extract (TCE) and its chemical constituents on RAW 264.7 macrophages. Six known compounds including magnoflorine and syringin were isolated by various chromatographic techniques from TCE and their structures were determined spectroscopically. A validated HPLC method was used to quantify magnoflorine and syringin in the extract. The immunomodulatory effects of TCE and its isolated compounds on chemotaxis, phagocytosis, production of inflammatory mediators including reactive oxygen species (ROS), nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokines which include tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and monocyte chemoattractant protein-1 (MCP-1) on macrophages were assessed. TCE increased the chemotaxis and phagocytic activity of macrophages and significantly enhanced the production of ROS, NO and pro-inflammatory cytokines. All alkaloids isolated, specifically magnoflorine showed remarkable inducing effects on the chemotaxis, phagocytic activity, ROS and NO productions and the secretions of IL-1β, TNF-α, IL6, PGE2 and MCP-1. In contrast, syringin potently reduced the chemotaxis, phagocytic activity, ROS and NO productions and secretions of IL-1β, TNF-α, IL6, PGE2 and MCP-1. TCE showed strong immunostimulant effects on various components of the immune system and these activities were possibly contributed mainly by the alkaloids specifically magnoflorine. TCE has potential to be developed as an effective natural immunostimulant for improvement of immune-related disorders.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  9. Fulltext Over-Expression of the Pikh Gene with a CaMV 35S Promoter Leads to Improved Blast Disease (Magnaporthe oryzae) Tolerance in Rice
    Azizi P, Rafii MY, Abdullah SN, Hanafi MM, Maziah M, Sahebi M, et al.
    Front Plant Sci, 2016;7:773.
    PMID: 27379107 DOI: 10.3389/fpls.2016.00773
    Magnaporthe oryzae is a rice blast fungus and plant pathogen that causes a serious rice disease and, therefore, poses a threat to the world's second most important food security crop. Plant transformation technology has become an adaptable system for cultivar improvement and to functionally analyze genes in plants. The objective of this study was to determine the effects (through over-expressing and using the CaMV 35S promoter) of Pikh on MR219 resistance because it is a rice variety that is susceptible to the blast fungus pathotype P7.2. Thus, a full DNA and coding DNA sequence (CDS) of the Pikh gene, 3172 bp, and 1206 bp in length, were obtained through amplifying the gDNA and cDNA template from a PH9-resistant rice variety using a specific primer. Agrobacterium-mediated transformation technology was also used to introduce the Pikh gene into the MR219 callus. Subsequently, transgenic plants were evaluated from the DNA to protein stages using polymerase chain reaction (PCR), semi-quantitative RT-PCR, real-time quantitative PCR and high performance liquid chromatography (HPLC). Transgenic plants were also compared with a control using a real-time quantification technique (to quantify the pathogen population), and transgenic and control plants were challenged with the local most virulent M. oryzae pathotype, P7.2. Based on the results, the Pikh gene encodes a hydrophilic protein with 18 sheets, 4 helixes, and 21 coils. This protein contains 401 amino acids, among which the amino acid sequence from 1 to 376 is a non-cytoplasmic region, that from 377 to 397 is a transmembrane region, and that from 398 to 401 is a cytoplasmic region with no identified disordered regions. The Pikh gene was up-regulated in the transgenic plants compared with the control plants. The quantity of the amino acid leucine in the transgenic rice plants increased significantly from 17.131 in the wild-type to 47.865 mg g(-1) in transgenic plants. The M. oryzae population was constant at 31, 48, and 72 h after inoculation in transgenic plants, while it was increased in the inoculated control plants. This study successfully clarified that over-expression of the Pikh gene in transgenic plants can improve their blast resistance against the M. oryzae pathotype P7.2.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  10. Fulltext Ergogenic, anti-diabetic and antioxidant attributes of selected Malaysian herbs: characterisation of flavonoids and correlation of functional activities
    Sallehuddin, N. A., Azizah Abdul Hamid, Salleh, S. Z., Nazia Abdul Majid, Hani Hafeeza Halim, Nurul Shazini Ramli, et al.
    International Food Research Journal, 2020;27(1):197-207.
    MyJurnal
    In the present work, aqueous ethanolic (60% ethanol) extracts from selected Malaysian herbs
    including Murraya koenigii L. Spreng, Lawsonia inermis L., Cosmos caudatus Kunth, Piper
    betle L., and P. sarmentosum Roxb. were evaluated for their ergogenic, anti-diabetic and
    antioxidant potentials. Results showed that the analysed herbs had ergogenic property and
    were able to activate 5'AMP-activated protein kinase (AMPK) in a concentration dependant
    manner. The highest AMPK activation was exhibited by M. koenigii extract which showed no
    significant (p > 0.05) difference with green tea (positive control). For anti-diabetic potential,
    the highest α-glucosidase inhibition was exhibited by M. koenigii extract with IC50 of 43.35
    ± 7.5 µg/mL, which was higher than acarbose (positive control). The determinations of free
    radical scavenging activity and total phenolics content (TPC) indicated that the analysed herbs
    had good antioxidant activity. However, C. caudatus extract showed superior antioxidant
    activity with IC50 against free radical and TPC of 21.12 ± 3.20 µg/mL and 221.61 ± 7.49 mg
    GAE/g, respectively. RP-HPLC analysis established the presence of flavonoids in the herbs
    wherein L. inermis contained the highest flavonoid (catechin, epicatechin, naringin and rutin)
    content (668.87 mg/kg of extract). Correlations between the analyses were conducted, and
    revealed incoherent trends. Overall, M. koenigii was noted to be the most potent herb for
    enhancement of AMPK activity and α-glucosidase inhibition but exhibited moderate antioxidant activity. These results revealed that the selected herbs could be potential sources of
    natural ergogenic and anti-diabetic/antioxidant agents due to their rich profile of phenolics.
    Further analysis in vivo should be carried out to further elucidate the mechanism of actions of
    these herbs as ergogenic aids and anti-diabetic/antioxidant agents.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  11. Fulltext Characterization of phenolics and biological activities of different solvent extracts from Withania somnifera fruit
    Tabassam, Q., Mehmood, T., Anwar, F., Saari, N., Qadir, R.
    International Food Research Journal, 2020;27(5):915-924.
    MyJurnal
    The present work studies the profiling of phenolic bioactive and in vitro biological (anticancer, antioxidant, and antimicrobial) activities of different solvent extracts from Withania
    somnifera fruit. Anticancer activity was performed using potato-disc assay and Agrobacterium tumefaciens. While antibacterial and antifungal evaluation was done by using disc diffusion method against bacterial (Staphylococcus aureus, S. epidermidis, Escherichia coli, and
    Klebsiella pneumonia) and fungal (Aspergillus flavus and Fusarium oxysporum) strains.
    Among different extraction solvents used, n-hexane extract exhibited the highest inhibition of
    tumour initiation (64%), whereas ethyl acetate (15%) was the lowest by using potato-disc
    assay. Highest total phenolic and total flavonoid contents were noted for methanolic (69.10
    GAE mg/g DW%) and n-hexane (29.45 CE mg/g DW%) extracts, respectively. For antioxidant potential, 2,2,1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC50) and reducing power EC50 were noted to be superior (0.6 and 2.0 mg/mL, respectively) for n-hexane
    extract. All the tested extracts showed considerable antibacterial and antifungal activity with
    the highest growth inhibition zones for K. pneumoniae (31.70 mm) and A. flavus (27.09 mm)
    were shown by n-hexane extract. High Performance Liquid Chromatographic (HPLC) analysis of individual phenolics (gallic acid, 2,288.48 mg/kg) indicated the highest contents of these
    compounds in n-hexane extract, which might explain the potent biological activities of this
    extract. Our findings revealed that the bioactive present in the tested fruit had significant
    potential as anticancer, antibacterial, and antifungal agents. Further studies are needed to
    elucidate the mechanism of actions of isolated bioactive against specific diseases such as
    cancer, especially in the case of n-hexane fraction.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  12. Fulltext Influence of vitamin D binding protein polymorphism, demographics and lifestyle factors on vitamin D status of healthy Malaysian pregnant women
    Lee SS, Ling KH, Tusimin M, Subramaniam R, Rahim KF, Loh SP
    BMC Pregnancy Childbirth, 2020 Nov 23;20(1):714.
    PMID: 33228578 DOI: 10.1186/s12884-020-03397-7
    BACKGROUND: Vitamin D deficiency (VDD) has been related to vitamin D binding protein (GC) gene polymorphism, demographics and lifestyle factors in different populations. However, previous studies only focused on demographic and lifestyle factors or genetic factors alone. Therefore, this cross-sectional study aimed to assess the association between GC gene polymorphism, demographics and lifestyle factors with VDD among Malaysian pregnant women.

    METHOD: Information on demographic characteristics, dietary vitamin D intake from supplement and food, time spent outdoors, skin type and clothing were collected using a questionnaire. Plasma total 25-hydroxyvitamin D (25OHD) levels were measured using an Ultra-High-Performance Liquid Chromatography (UHPLC). Maternal GC single nucleotide polymorphisms (SNPs) (rs4588 and rs7041) were determined using restriction fragment length polymorphism (RFLP) technique.

    RESULTS: Results showed that 50.2% of pregnant women were vitamin D deficient (25OHD high prevalence of maternal VDD found in this study suggests the need for urgent development and implementation of vitamin D supplementation or fortification strategies to reduce VDD among pregnant women. The discrepancy in the association between GC rs7041 gene polymorphism and VDD reflects the variation in the factors associated with VDD in pregnancy compared to non-pregnant state.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  13. Computational-aided design: minimal peptide sequence to block dengue virus transmission into cells
    Arumugam AC, Agharbaoui FE, Khazali AS, Yusof R, Abd Rahman N, Ahmad Fuaad AAH
    J Biomol Struct Dyn, 2020 Dec 31.
    PMID: 33382015 DOI: 10.1080/07391102.2020.1866074
    Dengue virus (DV) infection is one of the main public health concerns, affecting approximately 390 million people worldwide, as reported by the World Health Organization. Yet, there is no antiviral treatment for DV infection. Therefore, the development of potent and nontoxic anti-DV, as a complement for the existing treatment strategies, is urgently needed. Herein, we investigate a series of small peptides inhibitors of DV antiviral activity targeting the entry process as the promising strategy to block DV infection. The peptides were designed based on our previously reported peptide sequence, DN58opt (TWWCFYFCRRHHPFWFFYRHN), to identify minimal effective inhibitory sequence through molecular docking and dynamics studies. The in silico designed peptides were synthesized using conventional Fmoc solid-phase peptide synthesis chemistry, purified by RP-HPLC and characterized using LCMS. Later, they were screened for their antiviral activity. One of the peptides, AC 001, was able to reduce about 40% of DV plaque formation. This observation correlates well with the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) analysis - AC 001 showed the most favorable binding affinity through 60 ns simulations. Pairwise residue decomposition analysis has revealed four key residues that contributed to the binding of these peptides into the DV2 E protein pocket. This work identifies the minimal peptide sequence required to inhibit DV replication and explains the behavior observed on an atomic level using computational study.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  14. Fulltext Amino acid compounds released by the giant freshwater prawn Macrobrachium rosenbergii during ecdysis: a factor attracting cannibalistic behaviour?
    Juneta-Nor AS, Noordin NM, Azra MN, Ma HY, Husin NM, Ikhwanuddin M
    J Zhejiang Univ Sci B, 2020 10 13;21(10):823-834.
    PMID: 33043647 DOI: 10.1631/jzus.B2000126
    Ecdysis is a common phenomenon that happens throughout the life phase of the giant freshwater prawn Macrobrachium rosenbergii. It is vital to better understand the correlation between cannibalism and biochemical compound that exists during the moulting process. The objective of the present study was to determine the amino acid profile released by M. rosenbergii during the ecdysis process that promotes cannibalism. To accomplish this, changes in amino acid levels (total amino acid (TAA) and free amino acid (FAA)) of tissue muscle, exoskeleton, and sample water of culture medium from the moulting (E-stage) and non-moulting (C-stage) prawns were analysed using high-performance liquid chromatography (HPLC). Comparison study revealed that among the TAA compounds, proline and sarcosine of tissues from moulting prawn were found at the highest levels. The level of FAA from water that contains moulting prawns (E-stage) was dominated by tryptophan and proline. Significant values obtained in the present study suggested that these amino acid compounds act as a chemical cue to promote cannibalism in M. rosenbergii during ecdysis. The knowledge of compositions and compounds that were released during the moulting process should be helpful for better understanding of the mechanism and chemical cues that play roles on triggering cannibalism, and also for future dietary manipulation to improve feeding efficiencies and feeding management, which indirectly impacts productivity and profitability.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  15. Biosurfactants from Marine Cyanobacteria Collected in Sabah, Malaysia
    Mehjabin JJ, Wei L, Petitbois JG, Umezawa T, Matsuda F, Vairappan CS, et al.
    J Nat Prod, 2020 06 26;83(6):1925-1930.
    PMID: 32432877 DOI: 10.1021/acs.jnatprod.0c00164
    Chemical investigation of the organic extract from Moorea bouillonii, collected in Sabah, Malaysia, led to the isolation of three new chlorinated fatty acid amides, columbamides F (1), G (2), and H (3). The planar structures of 1-3 were established by a combination of mass spectrometric and NMR spectroscopic analyses. The absolute configuration of 1 was determined by Marfey's analysis of its hydrolysate and chiral-phase HPLC analysis after conversion and esterification with Ohrui's acid, (1S,2S)-2-(anthracene-2,3-dicarboximido)cyclohexanecarboxylic acid. Compound 1 showed biosurfactant activity by an oil displacement assay. Related known fatty acid amides columbamide D and serinolamide C exhibited biosurfactant activity with critical micelle concentrations of about 0.34 and 0.78 mM, respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  16. Fulltext An inhibited dopamine synthesizing cell model of AADC deficiency
    Melati Khalid, Mohamad Aris Mohd Moklas
    Life Sciences, Medicine and Biomedicine, 2019;3(2):1-7.
    MyJurnal
    Aromatic L-amino acid decarboxylase deficiency (AADC) is a rare autosomal recessive pediatric neurotransmitter disease. To date it remains poorly understood mainly due to an absence of a disease model. The dopaminergic neuroblastoma cell SH-SY5Y was chosen to develop our AADC deficiency model. These cells are not native dopamine synthesizers. Objective: To develop a dopamine-producing cellular model of AADC deficiency using SH-SY5Y neuroblastoma cells. Methods: Dopamine pathway proteins were identified with Western Blotting. Dopaminergic differentiation was attempted using all-trans retinoic acid (ATRA) with dopamine detection via HPLC-ECD post alumina extraction. Treatment with L-DOPA provided SH-SY5Y with excess precursor. RT-PCR was used to determine the expression of markers of mature neurons. Results: Western Blot screening identified AADC, dopamine β-hydroxylase and tyrosine hyrdoxylase proteins, indicative of a dopaminergic pathway. ATRA was unsuccessful in producing dopamine from the cells. L-DOPA treatment however, generated dopamine first visible as a HPLC-ECD peak 30 minutes post-incubation. Prior to this, SH-SY5Y dopamine synthesis from L-DOPA has never been documented. This de novo synthesis is then inhibited using benserazide to form our AADC deficiency cell model. RT-PCR showed that SH-SY5Y cells express markers of mature neurons in its ‘native’ state and is not affected by L-DOPA and benserazide treatment. This cell model will potentially benefit many areas of AADC deficiency research. Conclusion: SH-SY5Y cells produced HPLC-ECD measureable amounts of dopamine with the addition of L-DOPA. Our model of AADC deficiency is generated by quelling the dopamine production with Benserazide.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  17. Fulltext Folate content and availability in Malaysian cooked foods
    Chew SC, Khor GL, Loh SP
    Malays J Nutr, 2012 Dec;18(3):383-91.
    PMID: 24568079 MyJurnal
    Data on folate availability of Malaysian cooked foods would be useful for estimation of dietary folate intake; however such information is scarce.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  18. Fulltext Urinary amino acids profile of vegetarians and non-vegetarians
    Chia, Yoke Yin, Ton, So Ha
    Malays J Nutr, 2006;12(1):67-78.
    MyJurnal
    The objective of the study was to quantify and to profile the amino acids content in urine samples. The amino acids content in urine was determined in 162 individuals (62 young non-vegetarians aged 15-45 years, 24 elderly non-vegetarians aged 46-70 years, 40 young vegetarians and 36 elderly vegetarians) by high performance liquid chromatography (HPLC). The most common amino acids detected in the young and elderly individuals on vegetarian and non-vegetarian diets were phenylalanine, threonine, arginine and asparagine, while leucine, aspartic acid and alanine were not found in any urine samples in both groups. Isoleucine was not detected in the urine of vegetarians. The concentrations of the majority of essential amino acids were between 0.10 - 2.00 mgl24hrs except for histidine which had a range of 4.1 - 5.0 mgl24hrs. The concentrations of non-essential amino acids varied. Proline, glycine and tyrosine concentrations were between 0.10 - 1.00 mg/24hrs, while cysteine, glutamine, glutamic acid and cystine concentrations were between 11.0 - 21.0 mg124hrs. Asparagine and hydroxy-proline had a range of 0.10 - 5.00 mg/24hrs, while serine and arginine ranged between 31.0 - 50.0 mg124hrs. Isoleucine and serine were not detected in elderly vegetarians while histidine, glycine, glutamic acid and hydroxy-proline were not detected in elderly non-vegetarians. Isoleucine, glycine and hydroxy proline were detected in young non-vegetarians but not in young vegetarians. The levels of amino acids showed no significant statistical differences between young vegetarians and non-vegetarians as well as between elderly vegetarians and non-vegetarians. Phenylalanine, threonine and trypthophan were commonly detected in the lacto-ovo and lacto vegetarians, while valine, cysteine, arginine and asparagine were commonly detected in vegans. In conclusion, except for isoleucine, general differences were seen in urinary amino acid excretions between vegetarians and non-vegetarians even though the differences were statistically not significant. Therefore lacto-ovo diets could be nutritionally adequate as the nutrients were substituted by dairy or plant products.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  19. Fulltext Determination of Vitamin C, β-carotene and Riboflavin Contents in Five Green Vegetables Organically and Conventionally Grown
    Malays J Nutr, 2003;9(1):-.
    MyJurnal
    As consumer interest in organically grown vegetables is increasing in Malaysia, there is a need to answer whether the vegetables are more nutritious than those conventionally grown. This study investigates commercially available vegetables grown organically and conventionally, purchased from retailers to analyse â-carotene, vitamin C and riboflavin contents. Five types of green vegetables were selected, namely Chinese mustard (sawi) (Brassica juncea), Chinese kale (kailan) (Brassica alboglabra), lettuce (daun salad) (Lactuca sativa), spinach (bayam putih) (Amaranthus viridis) and swamp cabbage (kangkung) (Ipomoea aquatica). For vitamin analysis, a reverse-phase high performance liquid chromatography was used to identify and quantify β-carotene, vitamin C and riboflavin. The findings showed that not all of the organically grown vegetables were higher in vitamins than that conventionally grown. This study found that only swamp cabbage grown organically was highest in β-carotene , vitamin C and riboflavin contents among the entire samples studied. The various nutrients in organically grown vegetables need to be analysed for the generation of a database on nutritional value which is important for future research.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  20. Fulltext Dietary Fat and Fibre Intakes of Malaysian Adults: Issues and Implications when ‘Western Targets’ Are Set as Dietary Goals
    Malays J Nutr, 1997;3(2):-.
    MyJurnal
    This article examines the fat and fibre intakes of Malaysian adults and highlights discrepancies and practical limitations if these intakes are to match the levels for these nutrients advocated in the World Health Organisation (WHO) and American Heart Association (AHA) ‘diet models’. Local data on food consumption showed that the total fat intakes amongst Malaysian adults, contrary to common perception, were not high and the mean values obtained fell within the range of 40-66g or 22-26% kcal. As such, the dietary target of 30% kcal total fat or its intermediate target of 30-35% kcal, advocated by WHO and AHA mainly to address the problem of a high consumption of dietary fats in western populations, should not be adopted indiscriminately by Malaysians. Dietary fatty acid (FA) analysis by high performance liquid chromatography (HPLC) coupled with the use of food composition tables, showed that the typical Malaysian diet prepared with palm olein or palm olein-groundnut oil blends as cooking oil contained 3.2-4.0% kcal polyunsaturated fatty acids (PUFA), mainly as the w-6 linoleic acid, which is also the predominant essential fatty acid (EFA) in humans. This level of linoleic acid, with an ω-6/ ω--3 FA ratio approximating 10, is adequate for basal PUPA and EFA needs but fell short of the 4-10% kcal linoleic acid recommended by WHO (1993) to counter the effects of the cholesterol-raising saturated fatty acids (SFA). This raised upper limit of 10% kcal linoleic acid (previously 7% kcal), which equals the level of PUFA implied in the AHA diet model, appears unnecessarily high considering that the cholesterol-lowering potential of linoleic acid is maximum at about 6% kcal, while the health hazards associated with long-term high intakes of PUPA have never been completely dismissed. The new WHO lower limit for dietary linoleic acid (4% kcal) would have a controversial impact of raising the previous minimal 3% kcal EFA to above 4% kcal (linoleic + alpha-linolenic acids). Similarly, the WHO recommendation for total dietary fibre of 27-40g (equivalent to a daily combined intake of 400g of vegetables and fruits, 30g of which should come from pulses) appears at present, too high a dietary target for the average Malaysian adult whose habitual daily diet was estimated to contain about 180g of vegetables plus fruits, providing only about 13-16g total dietary fibre. Appropriately, an expert panel on Malaysian Dietary Guidelines has recommended instead, 20-30% kcal total fat containing 3-7% kcal PUFA, and 20-30g total dietary fibre for the local population.
    Matched MeSH terms: Chromatography, High Pressure Liquid
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