Displaying publications 901 - 920 of 10377 in total

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  1. Preparation and characterization of an amylase-triggered dextrin-linked graphene oxide anticancer drug nanocarrier and its vascular permeability
    Kiew SF, Ho YT, Kiew LV, Kah JCY, Lee HB, Imae T, et al.
    Int J Pharm, 2017 Dec 20;534(1-2):297-307.
    PMID: 29080707 DOI: 10.1016/j.ijpharm.2017.10.045
    We synthesized a dextrin (DEX)-conjugated graphene oxide (GO) nanocarrier (GO100-DEX) as a potential drug delivery system to respond to a tumor-associated stimulus, α-amylase, that has high permeability through the fenestrated endothelial barrier to the tumor site. At acidic pH and in the presence of α-amylase to simulate tumor conditions, GO100-DEX released a 1.5-fold higher amount of doxorubicin (DOX) than of GO100. Under the same conditions, the cytotoxic effects of GO100-DEX/DOX were 2-fold greater than those of free DOX and 2.9-fold greater than those of GO100/DOX. Employing an in vitro biomimetic microfluidic blood vessel model lined with human umbilical vein endothelial cells, we evaluated the tumor vasculature endothelial permeation of GO100-DEX and GO100 using dextrans of 10 and 70kDa for comparison and as standards to validate the microfluidic blood vessel model. The results showed that the permeabilities of GO100-DEX and GO100 were 4.3- and 4.9-fold greater than that of 70kDa dextran and 2.7- and 3.1-fold higher than that of 10kDa dextran, thus demonstrating the good permeability of the GO-based nanocarrier through the fenestrated endothelial barrier.
    Matched MeSH terms: Amylases/chemistry*; Antineoplastic Agents/chemistry*; Dextrans/chemistry; Dextrins/chemistry*; Doxorubicin/chemistry; Drug Carriers/chemistry*; Graphite/chemistry*; Oxides/chemistry*; Nanoparticles/chemistry*
  2. Optimization of headspace solid-phase microextraction for the determination of pesticide residues in vegetables and fruits
    Chai M, Tan G, Lal A
    Anal Sci, 2008 Feb;24(2):273-6.
    PMID: 18270422
    A headspace solid-phase microextraction method has been developed for the determination of 8 pesticides in vegetables and fruits by using gas chromatography with an electron capture detector. Two types of fibers (polyacrylate, 85 microm and polydimethylsiloxane, 100 microm) have been assayed and compared. The main factors: extraction and desorption parameters, ionic strength, and the effects of dilution and organic solvents, were studied and optimized. The optimized procedures resulted in more than 80% recovery for all the investigated vegetable and fruit samples with RSD values below 10%.
    Matched MeSH terms: Acetone/chemistry; Acrylates/chemistry; Methanol/chemistry; Dimethylpolysiloxanes/chemistry; Fruit/chemistry*; Silicones/chemistry; Sodium Chloride/chemistry; Vegetables/chemistry*; Water/chemistry
  3. Adsorption properties of cationic rhodamine B dye onto metals chloride-activated castor bean residue carbons
    Zhi LL, Zaini MA
    Water Sci Technol, 2017 02;75(3-4):864-880.
    PMID: 28234287 DOI: 10.2166/wst.2016.568
    This work was aimed to evaluate the feasibility of castor bean residue based activated carbons prepared through metals chloride activation. The activated carbons were characterized for textural properties and surface chemistry, and the adsorption data of rhodamine B were established to investigate the removal performance. Zinc chloride-activated carbon with specific surface area of 395 m(2)/g displayed a higher adsorption capacity of 175 mg/g. Magnesium chloride and iron(III) chloride are less toxic and promising agents for composite chemical activation. The adsorption data obeyed Langmuir isotherm and pseudo-second-order kinetics model. The rate-limiting step in the adsorption of rhodamine B is film diffusion. The positive values of enthalpy and entropy indicate that the adsorption is endothermic and spontaneous at high temperature.
    Matched MeSH terms: Castor Bean/chemistry*; Charcoal/chemistry*; Chlorides/chemistry*; Ferric Compounds/chemistry; Rhodamines/chemistry; Seeds/chemistry; Water Pollutants, Chemical/chemistry; Magnesium Chloride/chemistry; Zinc Compounds/chemistry
  4. Cellulose nanocomposite films with in situ generated silver nanoparticles using Cassia alata leaf extract as a reducing agent
    Sivaranjana P, Nagarajan ER, Rajini N, Jawaid M, Rajulu AV
    Int J Biol Macromol, 2017 Jun;99:223-232.
    PMID: 28237574 DOI: 10.1016/j.ijbiomac.2017.02.070
    Cotton linters were dissolved in aq. (8% LiOH+15% urea) that was pre-cooled to -12.5°C. Using this solution cellulose gel films were prepared by regeneration method with ethyl alcohol as a coagulant. These wet films were diffused with 10wt% Cassia alata leaf extract that acted as a reducing agent. The leaf extract diffused cellulose wet films were used as the matrix. The wet matrix films were dipped individually in lower concentrated 1-5mM aq.AgNO3 source solutions in the presence of sunlight and allowed the solutions to react with the diffused leaf extract reducing agent which in situ generated the silver nanoparticles (AgNPs) inside the films as well as in the source solution. The AgNPs formed in the source solution were observed by transmission electron microscope (TEM) and scanning electron microscope (SEM) while those formed in situ the films were observed by SEM and the particle size distribution was determined. The cellulose/AgNP composite films showed good antibacterial activity against Escherichia coli bacteria. These nanocomposite films were also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and tensile tests. At temperatures below 300°C, the thermal stability of the nanocomposite films was lower than that of the matrix due to the catalytic effect of AgNPs. The nanocomposite films also possessed good tensile properties. The ecofriendly cellulose/AgNP composite films with good antibacterial activity and tensile properties can be considered for medical applications like dressing materials.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry; Cassia/chemistry*; Cellulose/chemistry*; Plant Extracts/chemistry*; Silver/chemistry*; Plant Leaves/chemistry*; Reducing Agents/chemistry; Nanocomposites/chemistry*; Metal Nanoparticles/chemistry*
  5. Fulltext Optimization of process parameters in preparation of tocotrienol-rich red palm oil-based nanoemulsion stabilized by Tween80-Span 80 using response surface methodology
    Chong WT, Tan CP, Cheah YK, B Lajis AF, Habi Mat Dian NL, Kanagaratnam S, et al.
    PLoS One, 2018;13(8):e0202771.
    PMID: 30142164 DOI: 10.1371/journal.pone.0202771
    Red palm oil (RPO) is a natural source of Vitamin E (70-80% tocotrienol). It is a potent natural antioxidant that can be used in skin-care products. Its antioxidant property protects skin from inflammation and aging. In our work, a tocotrienol-rich RPO-based nanoemulsion formulation was optimized using response surface methodology (RSM) and formulated using high pressure homogenizer. Effect of the concentration of three independent variables [surfactant (5-15 wt%), co-solvent (10-30 wt%) and homogenization pressure (500-700 bar)] toward two response variables (droplet size, polydispersity index) was studied using central composite design (CCD) coupled to RSM. RSM analysis showed that the experimental data could be fitted into a second-order polynomial model and the coefficients of multiple determination (R2) is 0.9115. The optimized formulation of RPO-based nanoemulsion consisted of 6.09 wt% mixed surfactant [Tween 80/Span 80 (63:37, wt)], 20 wt% glycerol as a co-solvent via homogenization pressure (500 bar). The optimized tocotrienol-rich RPO-based nanoemulsion response values for droplet size and polydispersity index were 119.49nm and 0.286, respectively. The actual values of the formulated nanoemulsion were in good agreement with the predicted values obtained from RSM, thus the optimized compositions have the potential to be used as a nanoemulsion for cosmetic formulations.
    Matched MeSH terms: Chemistry, Pharmaceutical; Emulsions/chemistry*; Hexoses/chemistry*; Polysorbates/chemistry; Surface-Active Agents/chemistry*; Water/chemistry; Tocotrienols/chemistry; Nanostructures/chemistry*; Lipid Droplets/chemistry
  6. Tunable Schiff's base-cross-linked chitosan composite for the removal of reactive red 120 dye: Adsorption and mechanism study
    Jawad AH, Mubarak NSA, Abdulhameed AS
    Int J Biol Macromol, 2020 Jan 01;142:732-741.
    PMID: 31760013 DOI: 10.1016/j.ijbiomac.2019.10.014
    In this study, tunable Schiff's base-cross-linked chitosan-glutaraldehyde (CS-GLA) was modified and applied to remove reactive red 120 (RR120) dye from an aqueous solution. Different ratios of TiO2 nanoparticles, such as 25% TiO2 nanoparticles (CS-GLA/TNC-25) and 50% TiO2 nanoparticles (CS-GLA/TNC-50), were loaded into the CS-GLA's molecular structure. The adsorptive properties of CS-GLA, CS-GLA/TNC-25, and CS-GLA/TNC-50 for the RR120 dye in the aqueous solution were evaluated. CS-GLA/TNC-25 exhibited the best adsorptive property possibly because of the perfect balancing between the surface area and available amine (NH2) groups in the composite formulation. The impact of adsorption key parameters, such as adsorbent dosage (0.01-1.2 g), RR120 dye concentration (30-400 mg/L), solution pH (3-12), and contact time (0-400 min) were explored by batch adsorption mode. The adsorption was well described by the Freundlich model and pseudo-second order kinetic model. The adsorption capacity of CS-GLA/TNC-25 for RR120 dye was 103.1 mg/g at 303K. The adsorption mechanism of RR120 on the CS-GLA/TNC-25 surface can be assigned to various interactions, such as electrostatic attraction, n-π stacking, and H-bonding. Results indicate the potential application of CS-GLA/TNC-25 as environment-friendly biosorbent for removing acid and/or textile dyes, such as RR120, from aqueous environments.
    Matched MeSH terms: Amines/chemistry; Cross-Linking Reagents/chemistry*; Glutaral/chemistry*; Schiff Bases/chemistry*; Titanium/chemistry*; Triazines/chemistry*; Water Pollutants, Chemical/chemistry; Chitosan/chemistry*; Nanocomposites/chemistry*
  7. Fulltext Antifungal Activity of Aqueous Extracts of Some Dominant Algerian Medicinal Plants
    Salhi N, Mohammed Saghir SA, Terzi V, Brahmi I, Ghedairi N, Bissati S
    Biomed Res Int, 2017;2017:7526291.
    PMID: 29226147 DOI: 10.1155/2017/7526291
    Aim: This study investigated the antifungal properties of aqueous extracts obtained from indigenous plants that grow spontaneously in the Northern Sahara of Algeria. The activities of these plants in controlling two fungal species that belong to Fusarium genus were evaluated in an in vitro assay.

    Materials and Methods: Fresh aerial parts of four plant species (Artemisia herba alba, Cotula cinerea, Asphodelus tenuifolius, and Euphorbia guyoniana) were collected for the preparation of aqueous extracts. Two levels of dilution (10% and 20%) of the pure extracts were evaluated against Fusarium graminearum and Fusarium sporotrichioides.

    Results: The results of this study revealed that the A. herba alba, C. cinerea, A. tenuifolius, and E. guyoniana aqueous extracts are effective at both concentrations of 10% and 20% for the Fusarium mycelia growth inhibition. In particular, A. tenuifolius extract is effective against F. graminearum, whereas F. sporotrichioides mycelium growth is strongly affected by the E. guyoniana 20% extract. The phytochemical characterization of the compositions of the aqueous extracts has revealed that the presence of some chemical compounds (tannins, flavonoids, saponins, steroids, and alkaloids) is likely to be responsible for the antifungal activities sought.

    Conclusion: The antifungal properties of A. herba alba, C. cinerea, A. tenuifolius, and E. guyoniana make these plants of potential interest for the control of fungi affecting both wheat yield and safety.

    Matched MeSH terms: Alkaloids/chemistry; Antifungal Agents/chemistry; Flavonoids/chemistry; Plant Extracts/chemistry; Plants, Medicinal/chemistry*; Saponins/chemistry; Steroids/chemistry; Tannins/chemistry; Artemisia/chemistry*
  8. Aqueous chlorination of acebutolol: kinetics, transformation by-products, and mechanism
    Khalit WN, Tay KS
    Environ Sci Pollut Res Int, 2016 Feb;23(3):2521-9.
    PMID: 26423291 DOI: 10.1007/s11356-015-5470-y
    This study investigated the reaction kinetics and the transformation by-products of acebutolol during aqueous chlorination. Acebutolol is one of the commonly used β-blockers for the treatment of cardiovascular diseases. It has been frequently detected in the aquatic environment. In the kinetics study, the second-order rate constant for the reaction between acebutolol and chlorine (k app) was determined at 25 ± 0.1 °C. The degradation of acebutolol by free available chlorine was highly pH dependence. When the pH increased from 6 to 8, it was found that the k app for the reaction between acebutolol and free available chlorine was increased from 1.68 to 11.2 M(-1) min(-1). By comparing with the reported k app values, the reactivity of acebutolol toward free available chlorine was found to be higher than atenolol and metoprolol but lower than nadolol and propranolol. Characterization of the transformation by-products formed during the chlorination of acebutolol was carried out using liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometry. Seven major transformation by-products were identified. These transformation by-products were mainly formed through dealkylation, hydroxylation, chlorination, and oxidation reactions.
    Matched MeSH terms: Acebutolol/chemistry*; Adrenergic beta-Antagonists/chemistry; Antihypertensive Agents/chemistry*; Atenolol/chemistry; Chlorine/chemistry; Propranolol/chemistry; Water/chemistry; Water Pollutants, Chemical/chemistry*; Adrenergic beta-1 Receptor Antagonists/chemistry*
  9. Fulltext Impact of soil field water capacity on secondary metabolites, phenylalanine ammonia-lyase (PAL), maliondialdehyde (MDA) and photosynthetic responses of Malaysian kacip fatimah (Labisia pumila Benth)
    Jaafar HZ, Ibrahim MH, Mohamad Fakri NF
    Molecules, 2012 Jun 13;17(6):7305-22.
    PMID: 22695235 DOI: 10.3390/molecules17067305
    A randomized complete block design 2 × 4 experiment was designed and conducted for 15 weeks to characterize the relationships between production of total phenolics, flavonoid, anthocyanin, leaf gas exchange, total chlorophyll, phenylalanine ammonia-lyase (PAL) and malondialdehyde (MDA) activity in two varieties of Labisia pumila Benth, namely the var. alata and pumila, under four levels of evapotranspiration replacement (ER) (100%; well watered), (75%, moderate water stress), (50%; high water stress) and (25%; severe water stress). The production of total phenolics, flavonoids, anthocyanin, soluble sugar and relative leaf water content was affected by the interaction between varieties and SWC. As the ER levels decreased from 100% to 25%, the production of PAL and MDA activity increased steadily. At the highest (100%) ER L. pumila exhibited significantly higher net photosynthesis, apparent quantum yield, maximum efficiency of photosystem II (f(v)/f(m)) and lower dark respiration rates compared to the other treatment. The production of total phenolics, flavonoids and anthocyanin was also found to be higher under high water stress (50% ER replacement) compared to severe water stress (25% ER). From this study, it was observed that as net photosynthesis, apparent quantum yield and chlorophyll content were downregulated under high water stress the production of total phenolics, flavonoids and anthocyanin were upregulated implying that the imposition of high water stress can enhance the medicinal properties of L. pumila Benth.
    Matched MeSH terms: Anthocyanins/chemistry; Chlorophyll/chemistry; Flavonoids/chemistry; Phenols/chemistry; Soil/chemistry*; Sucrose/chemistry; Water/chemistry*; Plant Leaves/chemistry; Primulaceae/chemistry
  10. Fulltext Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications
    Ang TF, Maiangwa J, Salleh AB, Normi YM, Leow TC
    Molecules, 2018 05 07;23(5).
    PMID: 29735886 DOI: 10.3390/molecules23051100
    The variety of halogenated substances and their derivatives widely used as pesticides, herbicides and other industrial products is of great concern due to the hazardous nature of these compounds owing to their toxicity, and persistent environmental pollution. Therefore, from the viewpoint of environmental technology, the need for environmentally relevant enzymes involved in biodegradation of these pollutants has received a great boost. One result of this great deal of attention has been the identification of environmentally relevant bacteria that produce hydrolytic dehalogenases—key enzymes which are considered cost-effective and eco-friendly in the removal and detoxification of these pollutants. These group of enzymes catalyzing the cleavage of the carbon-halogen bond of organohalogen compounds have potential applications in the chemical industry and bioremediation. The dehalogenases make use of fundamentally different strategies with a common mechanism to cleave carbon-halogen bonds whereby, an active-site carboxylate group attacks the substrate C atom bound to the halogen atom to form an ester intermediate and a halide ion with subsequent hydrolysis of the intermediate. Structurally, these dehalogenases have been characterized and shown to use substitution mechanisms that proceed via a covalent aspartyl intermediate. More so, the widest dehalogenation spectrum of electron acceptors tested with bacterial strains which could dehalogenate recalcitrant organohalides has further proven the versatility of bacterial dehalogenators to be considered when determining the fate of halogenated organics at contaminated sites. In this review, the general features of most widely studied bacterial dehalogenases, their structural properties, basis of the degradation of organohalides and their derivatives and how they have been improved for various applications is discussed.
    Matched MeSH terms: Bacteria/chemistry; Bacterial Proteins/chemistry*; Environmental Pollutants/chemistry*; Esters/chemistry; Halogens/chemistry; Hydrocarbons, Halogenated/chemistry*; Hydrolases/chemistry*; Isoenzymes/chemistry; Pesticides/chemistry
  11. Fulltext Degradability enhancement of poly(lactic acid) by stearate-Zn(3)Al LDH nanolayers
    Eili M, Shameli K, Ibrahim NA, Wan Yunus WMZ
    Int J Mol Sci, 2012;13(7):7938-7951.
    PMID: 22942682 DOI: 10.3390/ijms13077938
    Recent environmental problems and societal concerns associated with the disposal of petroleum based plastics throughout the world have triggered renewed efforts to develop new biodegradable products compatible with our environment. This article describes the preparation, characterization and biodegradation study of poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites from PLA and stearate-Zn(3)Al LDH. A solution casting method was used to prepare PLA/stearate-Zn(3)Al LDH nanocomposites. The anionic clay Zn(3)Al LDH was firstly prepared by co-precipitation method from a nitrate salt solution at pH 7.0 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.83 Å to 40.10 Å. The morphology and properties of the prepared PLA/stearate-Zn(3)Al LDH nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), tensile tests as well as biodegradation studies. From the XRD analysis and TEM observation, the stearate-Zn(3)Al LDH lost its ordered stacking-structure and was greatly exfoliated in the PLA matrix. Tensile test results of PLA/stearate-Zn(3)Al LDH nanocomposites showed that the presence of around 1.0-3.0 wt % of the stearate-Zn(3)Al LDH in the PLA drastically improved its elongation at break. The biodegradation studies demonstrated a significant biodegradation rate improvement of PLA in the presence of stearate-Zn(3)Al LDH nanolayers. This effect can be caused by the catalytic role of the stearate groups in the biodegradation mechanism leading to much faster disintegration of nanocomposites than pure PLA.
    Matched MeSH terms: Enzymes, Immobilized/chemistry; Hydroxides/chemistry*; Nitrates/chemistry*; Polymers/chemistry*; Stearates/chemistry*; Aluminum Compounds/chemistry*; Zinc Compounds/chemistry*; Lactic Acid/chemistry*; Nanocomposites/chemistry
  12. Fulltext The impact of local surface changes in Borneo on atmospheric composition at wider spatial scales: coastal processes, land-use change and air quality
    Pyle JA, Warwick NJ, Harris NR, Abas MR, Archibald AT, Ashfold MJ, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3210-24.
    PMID: 22006963 DOI: 10.1098/rstb.2011.0060
    We present results from the OP3 campaign in Sabah during 2008 that allow us to study the impact of local emission changes over Borneo on atmospheric composition at the regional and wider scale. OP3 constituent data provide an important constraint on model performance. Treatment of boundary layer processes is highlighted as an important area of model uncertainty. Model studies of land-use change confirm earlier work, indicating that further changes to intensive oil palm agriculture in South East Asia, and the tropics in general, could have important impacts on air quality, with the biggest factor being the concomitant changes in NO(x) emissions. With the model scenarios used here, local increases in ozone of around 50 per cent could occur. We also report measurements of short-lived brominated compounds around Sabah suggesting that oceanic (and, especially, coastal) emission sources dominate locally. The concentration of bromine in short-lived halocarbons measured at the surface during OP3 amounted to about 7 ppt, setting an upper limit on the amount of these species that can reach the lower stratosphere.
    Matched MeSH terms: Atmosphere/chemistry*; Bromine/chemistry; Butadienes/chemistry; Carbanilides/chemistry; Formaldehyde/chemistry; Nitrogen Oxides/chemistry; Ozone/chemistry; Pentanes/chemistry; Trees/chemistry*; Arecaceae/chemistry*; Hemiterpenes/chemistry; Volatile Organic Compounds/chemistry
  13. Properties of the tray adhesive of an addition polymerizing silicone to impression tray materials
    Sulong MZ, Setchell DJ
    J Prosthet Dent, 1991 Dec;66(6):743-7.
    PMID: 1805022
    Adhesive bond strength studies for the tray adhesive of an addition vinyl polysiloxane (President) impression material were conducted with an acrylic resin, chromium-plated brass, and plastic trays. Tensile and shear stress studies were performed on the Instron Universal testing machine. Acrylic resin specimens roughened with 80-grit silicon carbide paper exhibited appreciably higher bond strengths compared with different types of tray material and methods of surface preparation.
    Matched MeSH terms: Acrylic Resins/chemistry*; Adhesives/chemistry*; Alloys/chemistry; Carbon/chemistry; Chromium/chemistry; Copper/chemistry; Dental Impression Materials/chemistry*; Polystyrenes/chemistry; Polyvinyls/chemistry*; Silicon/chemistry; Siloxanes/chemistry*; Zinc/chemistry
  14. Particle size analysis of nanocrystals: improved analysis method
    Keck CM
    Int J Pharm, 2010 May 5;390(1):3-12.
    PMID: 19733647 DOI: 10.1016/j.ijpharm.2009.08.042
    The influence of optical parameters, additional techniques (e.g. PIDS technology) and the importance of light microscopy were investigated by comparing laser diffraction data obtained via the conventional method and an optimized analysis method. Also the influence of a possible dissolution of nanocrystals during a measurement on the size result obtained was assessed in this study. The results reveal that dissolution occurs if unsaturated medium or microparticle saturated medium is used for the measurements. The dissolution is erratic and the results are not reproducible. Dissolution can be overcome by saturating the measuring medium prior to the measurement. If nanocrystals are analysed the dispersion medium should be saturated with the nanocrystals, because the solubility is higher than for coarse micro-sized drug material. The importance of using the optimized analysis method was proven by analysing 40 different nanosuspensions via the conventional versus the optimized sizing method. There was no large difference in the results obtained for the 40 nanosuspensions using the conventional method. This would have led to the conclusion, that all the 40 formulations investigated are physically stable. However, the analysis via the optimized method revealed that from 40 formulations investigated only four were physically stable. In conclusion an optimized analysis saves time and money and avoids misleading developments, because discrimination between "stable" and "unstable" can be done reliably at a very early stage of the development.
    Matched MeSH terms: Chemistry Techniques, Analytical/instrumentation; Chemistry Techniques, Analytical/methods*; Excipients/chemistry; Polyethylene Glycols/chemistry; Polysorbates/chemistry; Rutin/chemistry; Sodium Dodecyl Sulfate/chemistry; Vitamin E/chemistry; Cyclosporine/chemistry; Poloxamer/chemistry; Nanoparticles/chemistry*
  15. Fulltext Chemical Profile, Antioxidant Properties and Antimicrobial Activities of Malaysian Heterotrigona itama Bee Bread
    Suleiman JB, Mohamed M, Abu Bakar AB, Nna VU, Zakaria Z, Othman ZA, et al.
    Molecules, 2021 Aug 15;26(16).
    PMID: 34443531 DOI: 10.3390/molecules26164943
    The aim of the study was to determine the chemical profile, antioxidant properties and antimicrobial activities of Heterotrigona itama bee bread from Malaysia. The pH, presence of phytochemicals, antioxidant properties, total phenolic content (TPC) and total flavonoid content (TFC), as well as antimicrobial activities, were assessed. Results revealed a decrease in the pH of bee bread water extract (BBW) relative to bee bread ethanolic extract (BBE) and bee bread hot water extract (BBH). Further, alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, resins, glycosides and xanthoproteins were detected in BBW, BBH and BBE. Also, significant decreases in TPC, TFC, DPPH activity and FRAP were detected in BBW relative to BBH and BBE. We detected phenolic acids such as gallic acid, caffeic acid, trans-ferulic acid, trans 3-hydroxycinnamic acid and 2-hydroxycinnamic acid, and flavonoids such as quercetin, kaempferol, apigenin and mangiferin in BBE using high-performance liquid chromatography analysis. The strongest antimicrobial activity was observed in Klebsilla pneumonia (MIC50 1.914 µg/mL), followed by E. coli (MIC50 1.923 µg/mL), Shigella (MIC50 1.813 µg/mL) and Salmonella typhi (MIC50 1.617 µg/mL). Bee bread samples possess antioxidant and antimicrobial properties. Bee bread contains phenolic acids and flavonoids, and could be beneficial in the management and treatment of metabolic diseases.
    Matched MeSH terms: Alkaloids/chemistry; Anti-Infective Agents/chemistry; Antioxidants/chemistry; Bees/chemistry*; Flavonoids/chemistry; Glycosides/chemistry; Hymenoptera/chemistry; Phenols/chemistry; Propolis/chemistry; Saponins/chemistry; Tannins/chemistry; Terpenes/chemistry
  16. Fulltext Phenolic content and antioxidant activity of Hibiscus cannabinus L. seed extracts after sequential solvent extraction
    Yusri NM, Chan KW, Iqbal S, Ismail M
    Molecules, 2012 Oct 25;17(11):12612-21.
    PMID: 23099617 DOI: 10.3390/molecules171112612
    A sequential solvent extraction scheme was employed for the extraction of antioxidant compounds from kenaf (Hibiscus cannabinus L.) seeds. Yield of extracts varied widely among the solvents and was the highest for hexane extract (16.6% based on dry weight basis), while water extract exhibited the highest total phenolic content (18.78 mg GAE/g extract), total flavonoid content (2.49 mg RE/g extract), and antioxidant activities (p < 0.05). DPPH and hydroxyl radical scavenging, β-carotene bleaching, metal chelating activity, ferric thiocyanate and thiobarbituric acid reactive substances assays were employed to comprehensively assess the antioxidant potential of different solvent extracts prepared sequentially. Besides water, methanolic extract also exhibited high retardation towards the formation of hydroperoxides and thiobarbituric acid reactive substances in the total antioxidant activity tests (p < 0.05). As conclusion, water and methanol extracts of kenaf seed may potentially serve as new sources of antioxidants for food and nutraceutical applications.
    Matched MeSH terms: Biphenyl Compounds/chemistry; Chelating Agents/chemistry; Flavonoids/chemistry; Free Radicals/chemistry; Hexanes/chemistry; Iron/chemistry; Phenols/chemistry*; Picrates/chemistry; Plant Extracts/chemistry*; Seeds/chemistry*; Solvents/chemistry; Thiocyanates/chemistry; Water/chemistry; Free Radical Scavengers/chemistry*; Thiobarbituric Acid Reactive Substances/chemistry; beta Carotene/chemistry; Hibiscus/chemistry*
  17. Adsorption and photocatalytic degradation of anionic dyes on Chitosan/PVA/Na-Titanate/TiO2 composites synthesized by solution casting method
    Habiba U, Islam MS, Siddique TA, Afifi AM, Ang BC
    Carbohydr Polym, 2016 09 20;149:317-31.
    PMID: 27261756 DOI: 10.1016/j.carbpol.2016.04.127
    Chitosan/PVA/Na-titanate/TiO2 composite was synthesized by solution casting method. The composite was analyzed via Fourier Transform Infrared Spectroscopy, X-ray diffraction, Field Emission Scanning Electron Microscopy, Thermal gravimetric analysis and water stability test. Incorporation of Na-titanate shown decrease of crystallinity for chitosan but increase water stability. However, the composite structure was deteriorated with considerable weight loss in acidic medium. Two anionic dyes, methyl orange and congo red were used for the adsorption test. The adsorption behavior of the composites were described by pseudo-second-order kinetic model and Lagergren-first-order model for methyl orange and congo red, respectively. For methyl orange, adsorption was started with a promising decolorization rate. 99.9% of methyl orange dye was removed by the composite having higher weightage of chitosan and crystalline TiO2 phase. On the other hand, for the congo red the composite having higher chitosan and Na-titanate showed an efficient removal capacity of 95.76%. UV-vis results showed that the molecular backbone of methyl orange and congo red was almost destroyed when equilibrium was obtained, and the decolorization rate was reaching 100%. Kinetic study results showed that the photocatalytic degradation of methyl orange and congo red could be explained by Langmuir-Hinshelwood model. Thus, chitosan/PVA/Na-titanate/TiO2 possesses efficient adsorptivity and photocatalytic property for dye degradation.
    Matched MeSH terms: Coloring Agents/chemistry*; Oxides/chemistry*; Polyvinyl Alcohol/chemistry*; Titanium/chemistry*; Water Pollutants, Chemical/chemistry; Chitosan/chemistry*
  18. Low-melting-point polymeric nanoshells for thermal-triggered drug release under hyperthermia condition
    Dabbagh A, Mahmoodian R, Abdullah BJ, Abdullah H, Hamdi M, Abu Kasim NH
    Int J Hyperthermia, 2015;31(8):920-9.
    PMID: 26670340 DOI: 10.3109/02656736.2015.1094147
    The aim of this paper was to synthesise core-shell nanostructures comprised of mesoporous silica core and a low melting-point polyethylene glycol (PEG) nanoshell with a sharp gel-liquid phase transition for rapid drug release at hyperthermia temperature range.
    Matched MeSH terms: Antibiotics, Antineoplastic/chemistry; Doxorubicin/chemistry; Drug Carriers/chemistry*; Polyethylene Glycols/chemistry; Silicon Dioxide/chemistry; Nanoshells/chemistry*
  19. Effect of hydrolysed cellulose nanowhiskers on properties of montmorillonite/polylactic acid nanocomposites
    Arjmandi R, Hassan A, Haafiz MK, Zakaria Z, Islam MS
    Int J Biol Macromol, 2016 Jan;82:998-1010.
    PMID: 26592699 DOI: 10.1016/j.ijbiomac.2015.11.028
    Polylactic acid (PLA) nanocomposites reinforced with hybrid montmorillonite/cellulose nanowhiskers [MMT/CNW(SO4)] were prepared by solution casting. The CNW(SO4) nanofiller was first isolated from microcrystalline cellulose using acid hydrolysis treatment. PLA/MMT/CNW(SO4) hybrid nanocomposites were prepared by the addition of various amounts of CNW(SO4) [1-9 parts per hundred parts of polymer (phr)] into PLA/MMT nanocomposite at 5 phr MMT content, based on highest tensile strength values as reported previously. The biodegradability, thermal, tensile, morphological, water absorption and transparency properties of PLA/MMT/CNW(SO4) hybrid nanocomposites were investigated. The Biodegradability, thermal stability and crystallinity of hybrid nanocomposites increased compared to PLA/MMT nanocomposite and neat PLA. The highest tensile strength of hybrid nanocomposites was obtained by incorporating 1 phr CNW(SO4) [∼ 36 MPa]. Interestingly, the ductility of hybrid nanocomposites increased significantly by 87% at this formulation. The Young's modulus increased linearly with increasing CNW(SO4) content. This is due to the relatively good dispersion of nanofillers in the hybrid nanocomposites, as revealed by transmission electron microscopy. Fourier transform infrared spectroscopy indicated the formation of some polar interactions. In addition, water resistance of the hybrid nanocomposites improved and the visual transparency of neat PLA film did not affect by addition of CNW(SO4).
    Matched MeSH terms: Bentonite/chemistry*; Biocompatible Materials/chemistry; Cellulose/chemistry*; Polymers/chemistry*; Lactic Acid/chemistry*; Nanocomposites/chemistry*
  20. Antioxidant and α-Glucosidase Inhibitory Constituents from Hornstedtia Species of Malaysia
    Hashim SE, Sirat HM, Yen KH, Ismail IS, Matsuki SN
    Nat Prod Commun, 2015 Sep;10(9):1561-3.
    PMID: 26594759
    Seven compounds were isolated from the n-hexane and chloroform extracts of the flowers and leaves of four Hornstedtia species and their structures were identified using spectroscopic techniques as 3,7,4'-trimethylkaempferol (1), 3,7-dimethylkaempferol (2), 7,4'-dimethylkaempferol (3), 3,5-dimethylkaempferol (4), 3-methylkaempferol (5), stigmast-4-en-3-one (6), and 6-hydroxy-stigmast-4-en-3-one (7). Compounds 1 to 7 were isolated from these species for the first time. They were assayed for free radical scavenging and α-glucosidase inhibition activities. The DPPH assay showed that 3-methylkaempferol (5) was the most potent antioxidant agent with an IC50 value 78.6 µM, followed by 7,4'-dimethylkaempferol (3) (IC50 = 86.1 µM). For α-glucosidase inhibition activity, 3-methylkaempferol (5) exhibited significant inhibitory activity with an IC50 value 21.0 µM. The present study revealed that Hornstedtia species have potential activities as antioxidant and α-glucosidase inhibitors.
    Matched MeSH terms: Antioxidants/chemistry*; Biphenyl Compounds/chemistry; Picrates/chemistry; Plant Leaves/chemistry; Zingiberaceae/chemistry*; Glycoside Hydrolase Inhibitors/chemistry
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