Displaying publications 2041 - 2060 of 10379 in total

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  1. Fulltext Optical and Photoacoustic Properties of Laser-Ablated Silver Nanoparticles in a Carbon Dots Solution
    Sadrolhosseini AR, Krishnan G, Shafie S, Abdul Rashid S, Wadi Harun S
    Molecules, 2020 Dec 09;25(24).
    PMID: 33316885 DOI: 10.3390/molecules25245798
    This study used the carbon dots solution for the laser ablation technique to fabricate silver nanoparticles. The ablation time range was from 5 min to 20 min. Analytical methods, including Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, transmission electron microscopy, and Raman spectroscopy were used to categorize the prepared samples. The UV-visible and z-scan techniques provided optical parameters such as linear and nonlinear refractive indices in the range of 1.56759 to 1.81288 and 7.3769 × 10-10 cm2 W-1 to 9.5269 × 10-10 cm2 W-1 and the nonlinear susceptibility was measured in the range of 5.46 × 10-8 to 6.97 × 10-8 esu. The thermal effusivity of prepared samples, which were measured using the photoacoustic technique, were in the range of 0.0941 W s1/2 cm-2 K-1 to 0.8491 W s1/2 cm-2 K-1. The interaction of the prepared sample with fluoride was investigated using a Raman spectrometer. Consequently, the intensity of the Raman signal decreased with the increasing concentration of fluoride, and the detection limit is about 0.1 ppm.
    Matched MeSH terms: Carbon/chemistry*; Fluorides/chemistry; Silver/chemistry*; Nanocomposites/chemistry*; Metal Nanoparticles/chemistry*
  2. Optimization of Pectin Extraction from Sweet Potato Peels Using Citric Acid and its Emulsifying Properties
    Hamidon NH, Abang Zaidel DN, Mohd Jusoh YM
    Recent Pat Food Nutr Agric, 2020;11(3):202-210.
    PMID: 32031081 DOI: 10.2174/2212798411666200207102051
    BACKGROUND: Pectin is a natural polysaccharide that has been used widely as a stabilizer in food emulsion system.

    OBJECTIVE: This study aimed to optimize the yield of pectin extracted from sweet potato residue and investigate its emulsifying properties.

    METHODS: Response surface methodology (RSM) has been utilized to investigate the pectin extracted from sweet potato peels using citric acid as the extracting solvent. Investigation of the effect of different extraction conditions namely temperature (°C), time (min) and solution pH on pectin yield (%) were conducted. A Box-Benhken design with three levels of variation was used to optimize the extraction conditions.

    RESULTS: The optimal conditions determined were temperature 76°C, time 64 min and pH 1.2 with 65.2% yield of pectin. The degree of esterification (DE) of the sweet potato pectin was determined using Fourier Transform Infrared (FTIR) Spectroscopy. The pectin is high-methoxyl pectin with DE of 58.5%. Emulsifying properties of sweet potato pectin were investigated by measuring the zeta-potential, particle size and creaming index with addition of 0.4 and 1.0 wt % pectin to the emulsion.

    CONCLUSION: Extraction using citric acid could improve the pectin yield. Improved emulsion stability was observed with the addition of the sweet potato pectin.

    Matched MeSH terms: Pectins/chemistry*; Plant Extracts/chemistry*; Citric Acid/chemistry; Ipomoea batatas/chemistry*; Emulsifying Agents/chemistry*
  3. Structural and Biochemical Insights into the Inhibition of Human Acetylcholinesterase by G-Series Nerve Agents and Subsequent Reactivation by HI-6
    McGuire JR, Bester SM, Guelta MA, Cheung J, Langley C, Winemiller MD, et al.
    Chem Res Toxicol, 2021 03 15;34(3):804-816.
    PMID: 33538594 DOI: 10.1021/acs.chemrestox.0c00406
    The recent use of organophosphate nerve agents in Syria, Malaysia, Russia, and the United Kingdom has reinforced the potential threat of their intentional release. These agents act through their ability to inhibit human acetylcholinesterase (hAChE; E.C. 3.1.1.7), an enzyme vital for survival. The toxicity of hAChE inhibition via G-series nerve agents has been demonstrated to vary widely depending on the G-agent used. To gain insight into this issue, the structures of hAChE inhibited by tabun, sarin, cyclosarin, soman, and GP were obtained along with the inhibition kinetics for these agents. Through this information, the role of hAChE active site plasticity in agent selectivity is revealed. With reports indicating that the efficacy of reactivators can vary based on the nerve agent inhibiting hAChE, human recombinatorially expressed hAChE was utilized to define these variations for HI-6 among various G-agents. To identify the structural underpinnings of this phenomenon, the structures of tabun, sarin, and soman-inhibited hAChE in complex with HI-6 were determined. This revealed how the presence of G-agent adducts impacts reactivator access and placement within the active site. These insights will contribute toward a path of next-generation reactivators and an improved understanding of the innate issues with the current reactivators.
    Matched MeSH terms: Nerve Agents/chemistry; Acetylcholinesterase/chemistry; Cholinesterase Inhibitors/chemistry; Oximes/chemistry; Pyridinium Compounds/chemistry
  4. Fulltext Enhanced polyhydroxybutyrate (PHB) production by newly isolated rare actinomycetes Rhodococcus sp. strain BSRT1-1 using response surface methodology
    Trakunjae C, Boondaeng A, Apiwatanapiwat W, Kosugi A, Arai T, Sudesh K, et al.
    Sci Rep, 2021 01 21;11(1):1896.
    PMID: 33479335 DOI: 10.1038/s41598-021-81386-2
    Poly-β-hydroxybutyrate (PHB) is a biodegradable polymer, synthesized as carbon and energy reserve by bacteria and archaea. To the best of our knowledge, this is the first report on PHB production by a rare actinomycete species, Rhodococcus pyridinivorans BSRT1-1. Response surface methodology (RSM) employing central composite design, was applied to enhance PHB production in a flask scale. A maximum yield of 3.6 ± 0.5 g/L in biomass and 43.1 ± 0.5 wt% of dry cell weight (DCW) of PHB were obtained when using RSM optimized medium, which was improved the production of biomass and PHB content by 2.5 and 2.3-fold, respectively. The optimized medium was applied to upscale PHB production in a 10 L stirred-tank bioreactor, maximum biomass of 5.2 ± 0.5 g/L, and PHB content of 46.8 ± 2 wt% DCW were achieved. Furthermore, the FTIR and 1H NMR results confirmed the polymer as PHB. DSC and TGA analysis results revealed the melting, glass transition, and thermal decomposition temperature of 171.8, 4.03, and 288 °C, respectively. In conclusion, RSM can be a promising technique to improve PHB production by a newly isolated strain of R. pyridinivorans BSRT1-1 and the properties of produced PHB possessed similar properties compared to commercial PHB.
    Matched MeSH terms: Carbon/chemistry; Hydroxybutyrates/chemistry*; Polyesters/chemistry*; Polymers/chemistry*; Rhodococcus/chemistry*
  5. Preparation of methacrylamide-functionalized crosslinked chitosan by free radical polymerization for the removal of lead ions
    Sutirman ZA, Sanagi MM, Abd Karim KJ, Wan Ibrahim WA
    Carbohydr Polym, 2016 Oct 20;151:1091-1099.
    PMID: 27474659 DOI: 10.1016/j.carbpol.2016.06.076
    A new poly(methacrylamide) grafted crosslinked chitosan was prepared for removal of lead, Pb(II) ion from aqueous solution. Crosslinked chitosan, in beads form, was grafted with methacrylamide (MAm) using ammonium persulfate (APS) as free radical initiator. Evidence of grafting was determined by comparing FTIR, TGA, SEM and (13)C NMR analyses of chitosan and graft copolymer. The optimal conditions for grafting reaction were as follow: crosslinked chitosan beads (1g), MAm (17.62×10(-1)M), APS (2.63×10(-1)M), reaction time (3h) and temperature (60°C). The modified chitosan bead was then used in laboratory batch experiments to evaluate the removal of Pb(II) ion from water samples. The Langmuir and Freundlich adsorption models were also applied to describe the equilibrium isotherms. The results revealed that the adsorption of Pb(II) ions onto the beads fitted very well with the Langmuir model with the maximum capacity (qmax) of 250mgg(-1).
    Matched MeSH terms: Acrylamides/chemistry*; Free Radicals/chemistry; Lead/chemistry*; Water Pollutants, Chemical/chemistry*; Chitosan/chemistry*
  6. Gambir, "Gambir Sarawak" and toad venom
    Lim WJ, Yap AT, Mangudi M, Hu CY, Yeo CY, Eyo ZW, et al.
    Drug Test Anal, 2017 Mar;9(3):491-499.
    PMID: 27367276 DOI: 10.1002/dta.2034
    Matched MeSH terms: Amphibian Venoms/chemistry*; Plant Extracts/chemistry*; Plants, Medicinal/chemistry; Street Drugs/chemistry; Uncaria/chemistry*
  7. Fulltext Magnetic Properties of Polyvinyl Alcohol and Doxorubicine Loaded Iron Oxide Nanoparticles for Anticancer Drug Delivery Applications
    Nadeem M, Ahmad M, Akhtar MS, Shaari A, Riaz S, Naseem S, et al.
    PLoS One, 2016;11(6):e0158084.
    PMID: 27348436 DOI: 10.1371/journal.pone.0158084
    The current study emphasizes the synthesis of iron oxide nanoparticles (IONPs) and impact of hydrophilic polymer polyvinyl alcohol (PVA) coating concentration as well as anticancer drug doxorubicin (DOX) loading on saturation magnetization for target drug delivery applications. Iron oxide nanoparticles particles were synthesized by a reformed version of the co-precipitation method. The coating of polyvinyl alcohol along with doxorubicin loading was carried out by the physical immobilization method. X-ray diffraction confirmed the magnetite (Fe3O4) structure of particles that remained unchanged before and after polyvinyl alcohol coating and drug loading. Microstructure and morphological analysis was carried out by transmission electron microscopy revealing the formation of nanoparticles with an average size of 10 nm with slight variation after coating and drug loading. Transmission electron microscopy, energy dispersive, and Fourier transform infrared spectra further confirmed the conjugation of polymer and doxorubicin with iron oxide nanoparticles. The room temperature superparamagnetic behavior of polymer-coated and drug-loaded magnetite nanoparticles were studied by vibrating sample magnetometer. The variation in saturation magnetization after coating evaluated that a sufficient amount of polyvinyl alcohol would be 3 wt. % regarding the externally controlled movement of IONPs in blood under the influence of applied magnetic field for in-vivo target drug delivery.
    Matched MeSH terms: Antibiotics, Antineoplastic/chemistry; Doxorubicin/chemistry; Ferric Compounds/chemistry; Polyvinyl Alcohol/chemistry; Magnetite Nanoparticles/chemistry*
  8. Flavonoids-Rich Orthosiphon stamineus Extract as New Candidate for Angiotensin I-Converting Enzyme Inhibition: A Molecular Docking Study
    Shafaei A, Sultan Khan MS, F A Aisha A, Abdul Majid AM, Hamdan MR, Mordi MN, et al.
    Molecules, 2016 Nov 09;21(11).
    PMID: 27834876
    This study aims to evaluate the in vitro angiotensin-converting enzyme (ACE) inhibition activity of different extracts of Orthosiphon stamineus (OS) leaves and their main flavonoids, namely rosmarinic acid (RA), sinensetin (SIN), eupatorin (EUP) and 3'-hydroxy-5,6,7,4'-tetramethoxyflavone (TMF). Furthermore, to identify possible mechanisms of action based on structure-activity relationships and molecular docking. The in vitro ACE inhibition activity relied on determining hippuric acid (HA) formation from ACE-specific substrate (hippuryl-histidyl-leucine (HHL)) by the action of ACE enzyme. A High Performance Liquid Chromatography method combined with UV detection was developed and validated for measurement the concentration of produced HA. The chelation ability of OS extract and its reference compounds was evaluated by tetramethylmurexide reagent. Furthermore, molecular docking study was performed by LeadIT-FlexX: BioSolveIT's LeadIT program. OS ethanolic extract (OS-E) exhibited highest inhibition and lowest IC50 value (45.77 ± 1.17 µg/mL) against ACE compared to the other extracts. Among the tested reference compounds, EUP with IC50 15.35 ± 4.49 µg/mL had highest inhibition against ACE and binding ability with Zn (II) (56.03% ± 1.26%) compared to RA, TMF and SIN. Molecular docking studies also confirmed that flavonoids inhibit ACE via interaction with the zinc ion and this interaction is stabilized by other interactions with amino acids in the active site. In this study, we have demonstrated that changes in flavonoids active core affect their capacity to inhibit ACE. Moreover, we showed that ACE inhibition activity of flavonoids compounds is directly related to their ability to bind with zinc ion in the active site of ACE enzyme. It was also revealed that OS extract contained high amount of flavonoids other than RA, TMF, SIN and EUP. As such, application of OS extract is useful as inhibitors of ACE.
    Matched MeSH terms: Angiotensin-Converting Enzyme Inhibitors/chemistry*; Flavonoids/chemistry*; Peptidyl-Dipeptidase A/chemistry*; Plant Extracts/chemistry*; Orthosiphon/chemistry*
  9. Selective dual cholinesterase inhibitors from Aconitum laeve
    Ahmad H, Ahmad S, Shah SAA, Khan HU, Khan FA, Ali M, et al.
    J Asian Nat Prod Res, 2018 Feb;20(2):172-181.
    PMID: 28463565 DOI: 10.1080/10286020.2017.1319820
    New lycoctonine-type dual cholinesterase inhibitor, swatinine-C (1), along with three known norditerpenoid alkaloids, hohenackerine (2), aconorine (5) and lappaconitine (6) and two synthetically known but phytochemically new benzene derivatives, methyl 2-acetamidobenzoate (3) and methyl 4-[2-(methoxycarbonyl)anilino]-4-oxobutanoate (4), was isolated from the roots of A. laeve. Structures of new and known compounds (1-6) were established on the basis of latest spectroscopic techniques and by close comparison with the data available in literature. In vitro, compounds (1-6) were tested against AChE and BChE inhibitory activities. Compounds 1 and 2 showed competitive inhibition against AChE (IC50 = 3.7 μM, 4.53 μM) and BChE (IC50 = 12.23 μM, 9.94 μM), respectively. Compounds 5 and 6 showed promising noncompetitive type of inhibitory profile against AChE (IC50 = 2.51 and 6.13 μM) only. Compounds 3 and 4 showed weak inhibitory profile against both AChE and BChE.
    Matched MeSH terms: Aconitine/chemistry; Alkaloids/chemistry; Cholinesterase Inhibitors/chemistry; Plant Roots/chemistry; Aconitum/chemistry*
  10. Near-infrared activatable phthalocyanine-poly-L-glutamic acid conjugate: increased cellular uptake and light-dark toxicity ratio toward an effective photodynamic cancer therapy
    Kiew LV, Cheah HY, Voon SH, Gallon E, Movellan J, Ng KH, et al.
    Nanomedicine, 2017 05;13(4):1447-1458.
    PMID: 28214608 DOI: 10.1016/j.nano.2017.02.002
    In photodynamic therapy (PDT), the low absorptivity of photosensitizers in an aqueous environment reduces singlet oxygen generation efficiency and thereby decreases photosensitizing efficacy in biological conditions. To circumvent this problem, we designed a phthalocyanine-poly-L-glutamic acid conjugate (1-PG) made from a new phthalocyanine (Pc 1) monofunctionalized to allow adequate conjugation to PGA. The resulting 1-PG conjugate retained high absorptivity in the near-infrared (NIR) region at its λmax675nm in an aqueous environment. The 1-PG conjugate demonstrated good singlet oxygen generation efficiency, increased uptake by 4 T1 breast cancer cells via clathrin-mediated endocytosis, and enhanced photocytotoxic efficacy. The conjugate also displayed a high light-dark toxicity ratio, approximately 1.5-fold greater than zinc phthalocyanine at higher concentration (10 μM), an important feature for the reduction of dark toxicity and unwanted side effects. These results suggest that the 1-PG conjugate could be a useful alternative for deep tissue treatment with enhanced anti-cancer (PDT) efficacy.
    Matched MeSH terms: Indoles/chemistry*; Photosensitizing Agents/chemistry*; Glutamic Acid/chemistry*; Singlet Oxygen/chemistry; Nanoconjugates/chemistry*
  11. Multiboronic acid-conjugated chitosan scaffolds with glucose selectivity to insulin release
    Siddiqui NA, Billa N, Roberts CJ
    J Biomater Sci Polym Ed, 2017 Jun;28(8):781-793.
    PMID: 28278045 DOI: 10.1080/09205063.2017.1301774
    The principal challenge for the use of boronic acids (BA) as glucose sensors is their lack of specificity for glucose. We examined the selectivity of and insulin release from two boronic acids- (2-formyl-3-thienylboronic acid (FTBA) and 4-formylphenylboronic acid (FPBA)) conjugated chitosan scaffolds to glucose and fructose. Adsorption of glucose to BA: chitosan conjugates was dose-dependent up to 1:1 at 35 and 42% for FPBA and FTBA respectively but the FTBA conjugates adsorbed more glucose and fructose at respective FPBA ratios. The affinity of both BA conjugates to glucose decreased with increase in BA ratio. On the other hand, the affinity of both BA conjugates for fructose decreased from ratio 1:1 to 2:1 then rose again at 3:1. Insulin release from FPBA nanoparticles (FPBAINP) and FTBA nanoparticles (FTBAINP) were both concentration-dependent within glyceamically relevant values (1-3 mg/ml glucose and 0.002 mg/ml fructose). Furthermore, the total amounts of insulin released from FPBAINP in both the media were higher than from FTBAINP. Both FPBAINP and FTBAINP have the potential for development as a glucose-selective insulin delivery system in physiological settings.
    Matched MeSH terms: Boronic Acids/chemistry*; Drug Carriers/chemistry*; Insulin/chemistry*; Chitosan/chemistry*; Nanoparticles/chemistry
  12. Antioxidant activity, total phenolics and flavonoids contents: Should we ban in vitro screening methods?
    Granato D, Shahidi F, Wrolstad R, Kilmartin P, Melton LD, Hidalgo FJ, et al.
    Food Chem, 2018 Oct 30;264:471-475.
    PMID: 29853403 DOI: 10.1016/j.foodchem.2018.04.012
    As many studies are exploring the association between ingestion of bioactive compounds and decreased risk of non-communicable diseases, the scientific community continues to show considerable interest in these compounds. In addition, as many non-nutrients with putative health benefits are reducing agents, hydrogen donors, singlet oxygen quenchers or metal chelators, measurement of antioxidant activity using in vitro assays has become very popular over recent decades. Measuring concentrations of total phenolics, flavonoids, and other compound (sub)classes using UV/Vis spectrophotometry offers a rapid chemical index, but chromatographic techniques are necessary to establish structure-activity. For bioactive purposes, in vivo models are required or, at the very least, methods that employ distinct mechanisms of action (i.e., single electron transfer, transition metal chelating ability, and hydrogen atom transfer). In this regard, better understanding and application of in vitro screening methods should help design of future research studies on 'bioactive compounds'.
    Matched MeSH terms: Antioxidants/chemistry; Chelating Agents/chemistry; Flavonoids/chemistry; Metals/chemistry; Phenols/chemistry
  13. Equilibrium, kinetic and mechanism studies of Cu(II) and Cd(II) ions adsorption by modified chitosan beads
    Sutirman ZA, Sanagi MM, Abd Karim KJ, Wan Ibrahim WA, Jume BH
    Int J Biol Macromol, 2018 Sep;116:255-263.
    PMID: 29746971 DOI: 10.1016/j.ijbiomac.2018.05.031
    In this study, the Cu(II) and Cd(II) ions removal behavior of crosslinked chitosan beads grafted poly(methacrylamide) (abbreviated as crosslinked chitosan-g-PMAm) from single metal ion solutions was investigated. The modified chitosan beads presented a remarkable improvement in acid resistance. The batch experiments demonstrated that pH of solution played a significant role in adsorption. It was found that the adsorption of Cu(II) and Cd(II) were optimum at pH 4 and pH 5, respectively. The maximum adsorption capacities for Cu(II) and Cd(II) based on Langmuir equation were 140.9 mg g-1 and 178.6 mg g-1, respectively. Pseudo-second order gave a better fit for adsorption data with respect to linearity coefficients than pseudo-first order suggesting that chemisorption or electron transfer is the dominant mechanism of the metal ions onto crosslinked chitosan-g-PMAm. In addition, X-ray photoelectron spectroscopy (XPS) investigations revealed that adsorption of both metal ions took place on the surfaces of crosslinked chitosan-g-PMAm by chelation through CNH2, CO and CO groups. Overall, the modified chitosan has proved a promising adsorbent for removal of metal ions.
    Matched MeSH terms: Cadmium/chemistry*; Copper/chemistry*; Ions/chemistry*; Water Pollutants, Chemical/chemistry; Chitosan/chemistry*
  14. Photocatalytic degradation of oilfield produced water using graphitic carbon nitride embedded in electrospun polyacrylonitrile nanofibers
    Alias NH, Jaafar J, Samitsu S, Yusof N, Othman MHD, Rahman MA, et al.
    Chemosphere, 2018 Aug;204:79-86.
    PMID: 29653325 DOI: 10.1016/j.chemosphere.2018.04.033
    Separation and purification of oilfield produced water (OPW) is a major environmental challenge due to the co-production of the OPW during petroleum exploration and production operations. Effective capture of oil contaminant and its in-situ photodegradation is one of the promising methods to purify the OPW. Based on the photocatalytic capability of graphitic carbon nitride (GCN) which was recently rediscovered, photodegradation capability of GCN for OPW was investigated in this study. GCN was synthesized by calcination of urea and further exfoliated into nanosheets. The GCNs were incorporated into polyacrylonitrile nanofibers using electrospinning, which gave a liquid-permeable self-supporting photocatalytic nanofiber mat that can be handled by hand. The photocatalytic nanofiber demonstrated 85.4% degradation of OPW under visible light irradiation, and improved the degradation to 96.6% under UV light. Effective photodegradation of the photocatalytic nanofiber for OPW originates from synergetic effects of oil adsorption by PAN nanofibers and oil photodegradation by GCNs. This study provides an insight for industrial application on purification of OPW through photocatalytic degradation under solar irradiation.
    Matched MeSH terms: Nitriles/chemistry*; Water/chemistry*; Water Pollutants, Chemical/chemistry; Nanofibers/chemistry*; Oil and Gas Fields/chemistry*
  15. A new achievement in green degradation of aqueous organic pollutants under visible-light irradiation
    Abdollahi Y, Sabbaghi S, Abouzari-Lotf E, Jahangirian H, Sairi NA
    Water Sci Technol, 2018 Mar;77(5-6):1493-1504.
    PMID: 29595152 DOI: 10.2166/wst.2018.017
    The global attention has been focused on degradation of the environmental organic pollutants through green methods such as advanced oxidation processes (AOPs) under sunlight. However, AOPs have not yet been efficient in function of the photocatalyst that has been used. In this work, firstly, CaCu3Ti4O12 nanocomposite was simultaneously synthesized and decorated in different amounts of graphene oxide to enhance photodegradation of the organics. The result of the photocatalyst characterization showed that the sample with 8% graphene presented optimum photo-electrical properties such as low band gap energy and a great surface area. Secondly, the photocatalyst was applied for photodegradation of an organic model in a batch photoreactor. Thirdly, to scale up the process and optimize the efficiency, the photodegradation was modeled by multivariate semi-empirical methods. As the optimized condition showed, 45 mg/L of the methyl-orange has been removed at pH 5.8 by 0.96 g/L of the photocatalyst during 288 min of the light irradiation. Moreover, the photodegradation has been scaled up for industrial applications by determining the importance of the input effective variables according to the following organics order > photocatalyst > pH > irradiation time.
    Matched MeSH terms: Azo Compounds/chemistry; Graphite/chemistry; Oxides/chemistry; Water Pollutants, Chemical/chemistry*; Nanocomposites/chemistry*
  16. Influence of citric acid on the physical and biomineralization ability of freeze/thaw poly(vinyl alcohol) hydrogel
    Wahid MNA, Abd Razak SI, Abdul Kadir MR, Hassan R, Nayan NHM, Mat Amin KA
    J Biomater Appl, 2018 07;33(1):94-102.
    PMID: 29716417 DOI: 10.1177/0885328218771195
    This work reports the modification of freeze/thaw poly(vinyl alcohol) hydrogel using citric acid as the bioactive molecule for hydroxyapatite formation in simulated body fluid. Inclusion of 1.3 mM citric acid into the poly(vinyl alcohol) hydrogel showed that the mechanical strength, crystalline phase, functional groups and swelling ability were still intact. Adding citric acid at higher concentrations (1.8 and 2.3 mM), however, resulted in physically poor hydrogels. Presence of 1.3 mM of citric acid showed the growth of porous hydroxyapatite crystals on the poly(vinyl alcohol) surface just after one day of immersion in simulated body fluid. Meanwhile, a fully covered apatite layer on the poly(vinyl alcohol) surface plus the evidence of apatite forming within the hydrogel were observed after soaking for seven days. Gel strength of the soaked poly(vinyl alcohol)/citric acid-1.3 mM hydrogel revealed that the load resistance was enhanced compared to that of the neat poly(vinyl alcohol) hydrogel. This facile method of inducing rapid growth of hydroxyapatite on the hydrogel surface as well as within the hydrogel network can be useful for guided bone regenerative materials.
    Matched MeSH terms: Biocompatible Materials/chemistry*; Polyvinyl Alcohol/chemistry*; Durapatite/chemistry*; Citric Acid/chemistry*; Hydrogels/chemistry*
  17. The influences of thermal processing on phytochemicals and possible routes to the discovery of new phytochemical conjugates
    Wong FC, Chai TT, Xiao J
    Crit Rev Food Sci Nutr, 2019;59(6):947-952.
    PMID: 29787299 DOI: 10.1080/10408398.2018.1479681
    In our diets, many of the consumed foods are subjected to various forms of heating and thermal processing. Besides enhancing the taste, texture, and aroma of the foods, heating helps to sterilize and facilitate food storage. On the other hand, heating and thermal processing are frequently reported during the preparation of various traditional herbal medicines. In this review, we intend to highlight works by various research groups which reported on changes in phytochemicals and bioactivities, following thermal processing of selected plant-derived foods and herbal medicines. Relevant cases from plant-derived foods (garlic, coffee, cocoa, barley) and traditional herbal medicines (Panax ginseng, Polygonum multiforum, Aconitum carmichaelii Debeaux, Angelica sinensis Radix) will be presented in this review. Additionally, related works using pure phytochemical compounds will also be highlighted. In some of these cases, the amazing formation of new compounds were being reported. Maillard reaction could be concluded as the predominant pathway leading to the formation of new conjugates, along with other possibilities being suggested (degradation, transglycosylation, deglycosylation and dehydration). With collective efforts from all researchers, it is hoped that more details will be revealed and lead to the possible discovery of new, heat-mediated phytochemical conjugates.
    Matched MeSH terms: Hordeum/chemistry; Cacao/chemistry; Coffee/chemistry; Garlic/chemistry; Plants, Medicinal/chemistry
  18. Novel multiplex PCR-RFLP assay discriminates bovine, porcine and fish gelatin substitution in Asian pharmaceuticals capsule shells
    Sultana S, Hossain MAM, Naquiah NNA, Ali ME
    Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2018 Sep;35(9):1662-1673.
    PMID: 30028648 DOI: 10.1080/19440049.2018.1500719
    Gelatin is widely used in pharmaceuticals as a protective coating, such as soft and hard capsule shells. However, the animal source of gelatin is a sensitive issue because certain gelatins such as porcine and bovine gelatins are not welcome in Halal, Kosher and Hindus' consumer goods. Recently, we have documented DNA barcoding and multiplex PCR platforms for discriminating porcine, bovine and fish gelatins in various fish and confectionary products; but those assays were not self-authenticating and also not tested in highly refined pharmaceutical products. To address this knowledge gap, here we report a self-authenticating multiplex PCR-restriction fragment length polymorphism (RFLP) assay to identify animal sources of various gelatin in pharmaceutical capsules. Three different restriction enzymes, BsaAI, Hpy188I and BcoDI were used to yield distinctive RFLP patterns for gelatin-based bovine (26, 94 bp), fish (97, 198 bp) and porcine (17, 70 bp) DNA in control experiments. The specificity was cross-tested against 16 non-target species and the optimised assay was used to screen gelatin sources in 30 halal-branded pharmaceuticals capsule shells. Bovine and porcine DNA was found in 27 and 3 of the 30 different capsules products. The assay was suitable for detecting 0.1 to 0.01 ng total DNA extracted from pure and mixed gelatins. The study might be useful to authenticate and monitor halal, kosher, vegetarian and Hindu compliant pharmaceuticals, foods and cosmetics.
    Matched MeSH terms: Capsules/chemistry; Chemistry, Pharmaceutical; DNA/chemistry; Pharmaceutical Preparations/chemistry*; Gelatin/chemistry
  19. A tannin-based agent for coagulation and flocculation of municipal wastewater: Chemical composition, performance assessment compared to Polyaluminum chloride, and application in a pilot plant
    Hameed YT, Idris A, Hussain SA, Abdullah N
    J Environ Manage, 2016 Dec 15;184(Pt 3):494-503.
    PMID: 27789092 DOI: 10.1016/j.jenvman.2016.10.033
    Chemical composition and flocculation efficiency were investigated for a commercially produced tannin - based coagulant and flocculant (Tanfloc). The results of Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive Spectroscopy (EDX) confirmed what claimed about the chemical composition of Tanfloc. For moderate polluted municipal wastewater investigated in both jar test and pilot plant, Tanfloc showed high turbidity removal efficiency of approximately 90%, while removal efficiencies of BOD5 and COD were around 60%. According to floc size distribution, Tanfloc was able to show distinct performance compared to Polyaluminum chloride (PAC). While 90% of flocs produced by Tanfloc were smaller than 144 micron, they were smaller than 96 micron for PAC. Practically, zeta potential measurement showed the cationic nature of Tanfloc and suggested coincidence of charge neutralization and another flocculation mechanism (bridging or patch flocculation). Sludge Volumetric Index (SVI) measurements were in agreement with the numbers found in the literature, and they were less than 160 mL/g. Calcium cation as flocculation aid showed significant improvement of flocculation efficiency compared to other cations. Finally Tanfloc showed competing performance compared to PAC in terms of turbidity, BOD5 and COD removal, floc size and sludge characteristics.
    Matched MeSH terms: Aluminum Hydroxide/chemistry*; Sewage/chemistry; Tannins/chemistry*; Water Pollutants, Chemical/chemistry*; Waste Water/chemistry*
  20. Characterization of metabolites in different kiwifruit varieties by NMR and fluorescence spectroscopy
    Abdul Hamid NA, Mediani A, Maulidiani M, Abas F, Park YS, Leontowicz H, et al.
    J Pharm Biomed Anal, 2017 May 10;138:80-91.
    PMID: 28189049 DOI: 10.1016/j.jpba.2017.01.046
    It is known from our previous studies that kiwifruits, which are used in common human diet, have preventive properties of coronary artery disease. This study describes a combination of (1)H NMR spectroscopy, multivariate data analyses and fluorescence measurements in differentiating of some kiwifruit varieties, their quenching and antioxidant properties. A total of 41 metabolites were identified by comparing with literature data Chenomx database and 2D NMR. The binding properties of the extracted polyphenols against HSA showed higher reactivity of studied two cultivars in comparison with the common Hayward. The results showed that the fluorescence of HSA was quenched by Bidan as much as twice than by other fruits. The correlation between the binding properties of polyphenols in the investigated fruits, their relative quantification and suggested metabolic pathway was established. These results can provide possible application of fruit extracts in pharmaceutical industry.
    Matched MeSH terms: Antioxidants/chemistry; Fruit/chemistry*; Plant Extracts/chemistry; Actinidia/chemistry*; Polyphenols/chemistry
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