Displaying publications 2521 - 2540 of 10379 in total

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  1. Venalstonine and dioxokopsan derivatives from Kopsia fruticosa
    Kam TS, Choo YM
    Phytochemistry, 2004 Jul;65(14):2119-22.
    PMID: 15279982
    Two new venalstonine derivatives, viz., venacarpines A and B, and one new dioxokopsan derivative, kopsorinine, in addition to the kopsifolines A-F, and 11 other known alkaloids, were isolated from a Malayan Kopsia species. The structures of the new alkaloids were determined using NMR and MS analysis.
    Matched MeSH terms: Alkaloids/chemistry; Plant Extracts/chemistry; Plant Leaves/chemistry; Alstonia/chemistry*
  2. Alkaloids from Alstonia angustifolia
    Kam TS, Choo YM
    Phytochemistry, 2004 Mar;65(5):603-8.
    PMID: 15003424
    Six new alkaloids, viz., alstolactone, affinisine oxindole, lagumicine, N(4)-demethylalstonerine, N(4)-demethylalstonerinal, and 10-methoxycathafoline N(4)-oxide, in addition to 36 other known alkaloids, were obtained from the leaf extract of Alstonia angustifolia var. latifolia. The structures of the new alkaloids were determined using NMR and MS analysis.
    Matched MeSH terms: Alkaloids/chemistry*; Plant Extracts/chemistry; Plant Leaves/chemistry; Alstonia/chemistry*
  3. A new flavonoid and sulphur-containing amides from Glycosmis chlorosperma
    Rahmani M, Leng KW, Ismail HB, Hin TY, Sukari MA, Ali AM, et al.
    Nat Prod Res, 2004 Feb;18(1):85-8.
    PMID: 14974620
    A new flavonoid, dihydroglychalcone-A, was isolated from the leaves extract of Glycosmis chlorosperma in addition to two known sulphur-containing amides, dambullin and gerambullin. The structure of the new compound was assigned as 2'-hydroxy-4,6'-dimethoxy-3',4'-(2",2"-dimethylpyrano)dihydrochalcone. The extract of the leaves was also found to exhibit antimicrobial and cytotoxic activities.
    Matched MeSH terms: Flavonoids/chemistry*; Plant Extracts/chemistry; Plant Leaves/chemistry; Rutaceae/chemistry*
  4. Sorption of Cr(VI) and Cu(II) in aqueous solution by ethylenediamine modified rice hull
    Tang PL, Lee CK, Low KS, Zainal Z
    Environ Technol, 2003 Oct;24(10):1243-51.
    PMID: 14669804
    The sorption characteristics of Cr(VI) and Cu(II) by ethylenediamine modified rice hull from single and binary metal ion solutions were evaluated under various experimental conditions. Optimal Cr(VI) and Cu(II) removal from single metal ion solutions occurred at pH 2.0 and 5.5, respectively. Simultaneous removal of Cr(VI) and Cu(II) occurred at pH greater than 3.0. The sorption kinetics of Cr(VI) and Cu(II) from single and binary metal ion solutions were studied with reference to metal concentration, agitation rate and particle size. Sorption of Cr(VI) was more rapid than Cu(II). The kinetics of metal ion sorption fitted a pseudo-second order expression. The variation in the initial uptake rates was very small at an agitation rate beyond 150 rpm and sorption was generally independent of particle size. Equilibrium sorption data could be fitted into the Langmuir isotherm equation. Maximum sorption capacities of ethylenediamine modified rice hull for Cr(VI) at pH 2 and Cu(II) at pH 4 in single metal solutions were 0.45 and 0.06 mmol g(-1), respectively. This corresponds to an enhancement factor of 2.6 and 3 fold for Cr(VI) and Cu(II), respectively, compared to natural rice hull. A synergistic effect was observed for sorption of these ions in binary metal solutions.
    Matched MeSH terms: Carcinogens, Environmental/chemistry*; Chromium/chemistry*; Copper/chemistry*; Ethylenediamines/chemistry*
  5. Fulltext Identification and characterization of jasmonic acid- and linolenic acid-mediated transcriptional regulation of secondary laticifer differentiation in Hevea brasiliensis
    Loh SC, Othman AS, Veera Singham G
    Sci Rep, 2019 10 04;9(1):14296.
    PMID: 31586098 DOI: 10.1038/s41598-019-50800-1
    Hevea brasiliensis remains the primary crop commercially exploited to obtain latex, which is produced from the articulated secondary laticifer. Here, we described the transcriptional events related to jasmonic acid (JA)- and linolenic acid (LA)-induced secondary laticifer differentiation (SLD) in H. brasiliensis clone RRIM 600 based on RNA-seq approach. Histochemical approach proved that JA- and LA-treated samples resulted in SLD in H. brasiliensis when compared to ethephon and untreated control. RNA-seq data resulted in 86,614 unigenes, of which 2,664 genes were differentially expressed in JA and LA-induced secondary laticifer harvested from H. brasiliensis bark samples. Among these, 450 genes were unique to JA and LA as they were not differentially expressed in ethephon-treated samples compared with the untreated samples. Most transcription factors from the JA- and LA-specific dataset were classified under MYB, APETALA2/ethylene response factor (AP2/ERF), and basic-helix-loop-helix (bHLH) gene families that were involved in tissue developmental pathways, and we proposed that Bel5-GA2 oxidase 1-KNOTTED-like homeobox complex are likely involved in JA- and LA-induced SLD in H. brasiliensis. We also discovered alternative spliced transcripts, putative novel transcripts, and cis-natural antisense transcript pairs related to SLD event. This study has advanced understanding on the transcriptional regulatory network of SLD in H. brasiliensis.
    Matched MeSH terms: Cyclopentanes/chemistry; Organophosphorus Compounds/chemistry; alpha-Linolenic Acid/chemistry; Oxylipins/chemistry
  6. Identification and characterization of antibacterial compound(s) of cockroaches (Periplaneta americana)
    Ali SM, Siddiqui R, Ong SK, Shah MR, Anwar A, Heard PJ, et al.
    Appl Microbiol Biotechnol, 2017 Jan;101(1):253-286.
    PMID: 27743045 DOI: 10.1007/s00253-016-7872-2
    Infectious diseases remain a significant threat to human health, contributing to more than 17 million deaths, annually. With the worsening trends of drug resistance, there is a need for newer and more powerful antimicrobial agents. We hypothesized that animals living in polluted environments are potential sources of antimicrobials. Under polluted milieus, organisms such as cockroaches encounter different types of microbes, including superbugs. Such creatures survive the onslaught of superbugs and are able to ward off disease by producing antimicrobial substances. Here, we characterized antibacterial properties in extracts of various body organs of cockroaches (Periplaneta americana) and showed potent antibacterial activity in crude brain extract against methicillin-resistant Staphylococcus aureus and neuropathogenic Escherichia coli K1. The size-exclusion spin columns revealed that the active compound(s) are less than 10 kDa in molecular mass. Using cytotoxicity assays, it was observed that pre-treatment of bacteria with lysates inhibited bacteria-mediated host cell cytotoxicity. Using spectra obtained with LC-MS on Agilent 1290 infinity liquid chromatograph, coupled with an Agilent 6460 triple quadruple mass spectrometer, tissues lysates were analysed. Among hundreds of compounds, only a few homologous compounds were identified that contained the isoquinoline group, chromene derivatives, thiazine groups, imidazoles, pyrrole-containing analogs, sulfonamides, furanones, and flavanones and known to possess broad-spectrum antimicrobial properties and anti-inflammatory, anti-tumour, and analgesic properties. Further identification, characterization, and functional studies using individual compounds can act as a breakthrough in developing novel therapeutics against various pathogens including superbugs.
    Matched MeSH terms: Animal Structures/chemistry; Anti-Bacterial Agents/chemistry; Cell Extracts/chemistry*; Cockroaches/chemistry*
  7. Fulltext The Pharmacological Potential of Oil Palm Phenolics (OPP) Individual Components
    Syarifah-Noratiqah SB, Zulfarina MS, Ahmad SU, Fairus S, Naina-Mohamed I
    Int J Med Sci, 2019;16(5):711-719.
    PMID: 31217739 DOI: 10.7150/ijms.29934
    The oil palm tree (Elaeis guineensis) from the family Arecaceae is a high oil-producing agricultural crop. A significant amount of vegetation liquor is discarded during the palm oil milling process amounting to 90 million tons per year around the world. This water-soluble extract is rich in phenolic compounds known as Oil Palm Phenolics (OPP). Several phenolic acids including the three isomers of caffeoylshikimic acid (CFA), p-hydroxybenzoic acid (PHBA), protocatechuic acid (PCA) and hydroxytyrosol are among the primary active ingredients in the OPP. Previous investigations have reported several positive pharmacological potentials by OPP such as neuroprotective and atheroprotective effects, anti-tumor and reduction in Aβ deposition in Alzheimer's disease model. In the current review, the pharmacological potential for CFA, PHBA, PCA and hydroxytyrosol is carefully reviewed and evaluated.
    Matched MeSH terms: Antioxidants/chemistry; Phenols/chemistry*; Arecaceae/chemistry*; Hydroxybenzoates/chemistry
  8. Utilization of waste fish oil and glycerol as carbon sources for polyhydroxyalkanoate production by Salinivibrio sp. M318
    Van Thuoc D, My DN, Loan TT, Sudesh K
    Int J Biol Macromol, 2019 Dec 01;141:885-892.
    PMID: 31513855 DOI: 10.1016/j.ijbiomac.2019.09.063
    A moderately halophilic bacterium isolated from fermenting shrimp paste, Salinivibrio sp. M318 was found capable of using fish sauce and mixtures of waste fish oil and glycerol as nitrogen and carbon sources, respectively, for poly(3-hydroxybutyrate) (PHB) production. A cell dry weight (CDW) of up to 10 g/L and PHB content of 51.7 wt% were obtained after 48 h of cultivation in flask experiment. Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] was synthesized when 1,4-butanediol, γ-butyrolactone, or sodium 4-hydroxybutyrate was added as precursors to the culture medium. The biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] was achieved by supplying precursors such as sodium valerate, sodium propionate, and sodium heptanoate. Salinivibrio sp. M318 was able to accumulate the above mentioned PHAs during the growth phase. High CDW of 69.1 g/L and PHB content of 51.5 wt% were obtained by strain Salinivibrio sp. M318 after 78 h of cultivation in fed-batch culture. The results demonstrate Salinivibrio sp. M318 to be a promising wild-type bacterium for the production of PHA from aquaculture residues.
    Matched MeSH terms: Carbon/chemistry*; Fish Oils/chemistry*; Glycerol/chemistry*; Nitrogen/chemistry
  9. Colloid mobilization and heavy metal transport in the sampling of soil solution from Duckum soil in South Korea
    Lee S, Ko IW, Yoon IH, Kim DW, Kim KW
    Environ Geochem Health, 2019 Feb;41(1):469-480.
    PMID: 29574658 DOI: 10.1007/s10653-018-0099-7
    Colloid mobilization is a significant process governing colloid-associated transport of heavy metals in subsurface environments. It has been studied for the last three decades to understand this process. However, colloid mobilization and heavy metal transport in soil solutions have rarely been studied using soils in South Korea. We investigated the colloid mobilization in a variety of flow rates during sampling soil solutions in sand columns. The colloid concentrations were increased at low flow rates and in saturated regimes. Colloid concentrations increased 1000-fold higher at pH 9.2 than at pH 7.3 in the absence of 10 mM NaCl solution. In addition, those were fourfold higher in the absence than in the presence of the NaCl solution at pH 9.2. It was suggested that the mobility of colloids should be enhanced in porous media under the basic conditions and the low ionic strength. In real field soils, the concentrations of As, Cr, and Pb in soil solutions increased with the increase in colloid concentrations at initial momentarily changed soil water pressure, whereas the concentrations of Cd, Cu, Fe, Ni, Al, and Co lagged behind the colloid release. Therefore, physicochemical changes and heavy metal characteristics have important implications for colloid-facilitated transport during sampling soil solutions.
    Matched MeSH terms: Colloids/chemistry*; Soil/chemistry*; Soil Pollutants/chemistry*; Metals, Heavy/chemistry*
  10. Fulltext Antioxidants and α-glucosidase inhibitors from Neptunia oleracea fractions using 1H NMR-based metabolomics approach and UHPLC-MS/MS analysis
    Lee SY, Mediani A, Ismail IS, Maulidiani, Abas F
    BMC Complement Altern Med, 2019 Jan 07;19(1):7.
    PMID: 30616569 DOI: 10.1186/s12906-018-2413-4
    BACKGROUND: Neptunia oleracea is a plant cultivated as vegetable in Southeast Asia. Previous works have revealed the potential of this plant as a source of natural antioxidants and α-glucosidase inhibitors. Continuing our interest on this plant, the present work is focused in identification of the bioactive compounds from different polarity fractions of N. oleracea, namely hexane (HF), chloroform (CF), ethyl acetate (EF) and methanol (MF).

    METHODS: The N. oleracea fractions were obtained using solid phase extraction (SPE). A metabolomics approach that coupled the use of proton nuclear magnetic resonance (1H NMR) with multivariate data analysis (MVDA) was applied to distinguish the metabolite variations among the N. oleracea fractions, as well as to assess the correlation between metabolite variation and the studied bioactivities (DPPH free radical scavenging and α-glucosidase inhibitory activities). The bioactive fractions were then subjected to ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis to profile and identify the potential bioactive constituents.

    RESULTS: The principal component analysis (PCA) discriminated EF and MF from the other fractions with the higher distributions of phenolics. Partial least squares (PLS) analysis revealed a strong correlation between the phenolics and the studied bioactivities in the EF and the MF. The UHPLC-MS/MS profiling of EF and MF had tentatively identified the phenolics present. Together with some non-phenolic metabolites, a total of 37 metabolites were tentatively assigned.

    CONCLUSIONS: The findings of this work supported that N. oleracea is a rich source of phenolics that can be potential antioxidants and α-glucosidase inhibitors for the management of diabetes. To our knowledge, this study is the first report on the metabolite-bioactivity correlation and UHPLC-MS/MS analysis of N. oleracea fractions.

    Matched MeSH terms: Antioxidants/chemistry; Fabaceae/chemistry*; Plant Extracts/chemistry*; Glycoside Hydrolase Inhibitors/chemistry
  11. Estimation of carbon pool in soil, above and below ground vegetation at different types of mangrove forests in Peninsular Malaysia
    Rozainah MZ, Nazri MN, Sofawi AB, Hemati Z, Juliana WA
    Mar Pollut Bull, 2018 Dec;137:237-245.
    PMID: 30503430 DOI: 10.1016/j.marpolbul.2018.10.023
    This paper evaluated the total carbon stock of mangrove ecosystems in two contrasting sites: a fishing village in Delta Kelantan (DK) and Ramsar sites in Johor Park (JP). In both sites, aboveground carbon was significantly higher than belowground carbon, and stems contained more carbon than leaf and root partitions. The average carbon concentration of individual mangrove species (44.9-48.1%) was not significantly different but the larger biomass of the DK samples resulted in vegetation carbon stock that was higher than that in JP. Season played an important role in soil carbon stock-a pronounced wet season in DK coincided with the dry season in JP. The total carbon pool was estimated to be 427.88 t ha-1 in JP and 512.51 t ha-1 in DK, where at least 80% was contributed by soil carbon. The carbon dioxide equivalent was 1570.32 t ha-1 CO2e (JP) and 1880.91 t ha-1 CO2e (DK).
    Matched MeSH terms: Plants/chemistry; Soil/chemistry*; Plant Leaves/chemistry; Plant Roots/chemistry
  12. Goniolanceolatins A-H, Cytotoxic Bis-styryllactones from Goniothalamus lanceolatus
    Bihud NV, Rasol NE, Imran S, Awang K, Ahmad FB, Mai CW, et al.
    J Nat Prod, 2019 09 27;82(9):2430-2442.
    PMID: 31433181 DOI: 10.1021/acs.jnatprod.8b01067
    Eight new bis-styryllactones, goniolanceolatins A-H (1-8), possessing a rare α,β-unsaturated δ-lactone moiety with a (6S)-configuration, were isolated from the CH2Cl2 extract of the stembark and roots of Goniothalamus lanceolatus Miq., a plant endemic to Malaysia. Absolute structures were established through extensive 1D- and 2D-NMR data analysis, in combination with electronic dichroism (ECD) data. All of the isolates were evaluated for their cytotoxicity against human lung and colorectal cancer cell lines. Compounds 2 and 4 showed cytotoxicity, with IC50 values ranging from 2.3 to 4.2 μM, and were inactive toward human noncancerous lung and colorectal cells. Compounds 1, 3, 6, 7, and 8 showed moderate to weak cytotoxicity. Docking studies of compounds 2 and 4 showed that they bind with EGFR tyrosine kinase and cyclin-dependent kinase 2 through hydrogen bonding interactions with the important amino acids, including Lys721, Met769, Asn818, Arg157, Ile10, and Glu12.
    Matched MeSH terms: Antineoplastic Agents, Phytogenic/chemistry; Lactones/chemistry; Plant Extracts/chemistry; Goniothalamus/chemistry*
  13. Ultrasound-assisted packed-bed extraction of hypericin from Hypericum perforatum L. and optimization by response surface methodology
    Tahmasebi-Boldaji R, Hatamipour MS, Khanahmadi M, Sadeh P, Najafipour I
    Ultrason Sonochem, 2019 Oct;57:89-97.
    PMID: 31208622 DOI: 10.1016/j.ultsonch.2019.05.018
    This paper presents the successful application of ultrasound-assisted packed-bed (UAE-PB) method for the extraction of hypericin from the Hypericum perfuratum L. The Soxhlet system was utilized for the determination of suitable solvent from ethanol, methanol or from the mixture of different proportions of ethanol-methanol. The mixture of 50:50 v/v ethanol-methanol was obtained to be the most suitable solvent since it led to the highest extraction amount of hypericin. The extraction amount of hypericin increased by 13.6% and 21.4% when the solvent changed from pure methanol to the mixture of 50:50 v/v ethanol-methanol for the extraction time of 3 and 8 h, respectively. Subsequently, the extraction was conducted through the UAE-PB, and the effects of temperature, time, and the ratio of solvent to the dried plant were studied. The response surface method (RSM) was used to investigate the effect of parameters on the extraction in the UAE-PB system. At the temperature of 60 °C, extraction time of 105 min, and the solvent to plant ratio of 15.3, the maximum extraction yield of hypericin was achieved. In the optimal conditions, the amount of extraction was 0.112 mg hypericin/g dried plant, which was in accordance with the optimized predicted value (0.111 mg hypericin/g dried plant) from Design-Expert software.
    Matched MeSH terms: Ethanol/chemistry; Methanol/chemistry; Solvents/chemistry; Hypericum/chemistry*
  14. Fulltext Isolation and Characterization of Lactobacillus spp. from Kefir Samples in Malaysia
    Talib N, Mohamad NE, Yeap SK, Hussin Y, Aziz MNM, Masarudin MJ, et al.
    Molecules, 2019 Jul 17;24(14).
    PMID: 31319614 DOI: 10.3390/molecules24142606
    Kefir is a homemade, natural fermented product comprised of a probiotic bacteria and yeast complex. Kefir consumption has been associated with many advantageous properties to general health, including as an antioxidative, anti-obesity, anti-inflammatory, anti-microbial, and anti-tumor moiety. This beverage is commonly found and consumed by people in the United States of America, China, France, Brazil, and Japan. Recently, the consumption of kefir has been popularized in other countries including Malaysia. The microflora in kefir from different countries differs due to variations in culture conditions and the starter media. Thus, this study was aimed at isolating and characterizing the lactic acid bacteria that are predominant in Malaysian kefir grains via macroscopic examination and 16S ribosomal RNA gene sequencing. The results revealed that the Malaysian kefir grains are dominated by three different strains of Lactobacillus strains, which are Lactobacillus harbinensis, Lactobacillusparacasei, and Lactobacillus plantarum. The probiotic properties of these strains, such as acid and bile salt tolerances, adherence ability to the intestinal mucosa, antibiotic resistance, and hemolytic test, were subsequently conducted and extensively studied. The isolated Lactobacillus spp. from kefir H maintained its survival rate within 3 h of incubation at pH 3 and pH 4 at 98.0 ± 3.3% and 96.1 ± 1.7% of bacteria growth and exhibited the highest survival at bile salt condition at 0.3% and 0.5%. The same isolate also showed high adherence ability to intestinal cells at 96.3 ± 0.01%, has antibiotic resistance towards ampicillin, penicillin, and tetracycline, and showed no hemolytic activity. In addition, the results of antioxidant activity tests demonstrated that isolated Lactobacillus spp. from kefir G possessed high antioxidant activities for total phenolic content (TPC), total flavonoid content (TFC), ferric reducing ability of plasma (FRAP), and 1,1-diphenyl-2-picryl-hydrazine (DPPH) assay compared to other isolates. From these data, all Lactobacillus spp. isolated from Malaysian kefir serve as promising candidates for probiotics foods and beverage since they exhibit potential probiotic properties and antioxidant activities.
    Matched MeSH terms: Antioxidants/chemistry*; Lactobacillus/chemistry; Probiotics/chemistry; Lactobacillus plantarum/chemistry
  15. GC-MS analysis of metabolites from soxhlet extraction, ultrasound-assisted extraction and supercritical fluid extraction of Salacca zalacca flesh and its alpha-glucosidase inhibitory activity
    Saleh MSM, Bukhari DAM, Siddiqui MJA, Kasmuri AR, Murugesu S, Khatib A
    Nat Prod Res, 2020 May;34(9):1341-1344.
    PMID: 30678487 DOI: 10.1080/14786419.2018.1560295
    Different extraction processes were employed to extract bioactive metabolites from Salacca zalacca flesh by a range of aqueous and organic solvents. The highest extraction yield was obtained by 50% ethanol extract of SE (73.18 ± 4.35%), whereas SFE_1 showed the lowest yield (0.42 ± 0.08%). All extracts were evaluated for in vitro α-glucosidase inhibitory activity, measured by their IC50 values in comparison to that of quercetin, the positive control (IC50 = 2.7 ± 0.7 μg/mL). The lowest α-glucosidase inhibitory activity was indicated by water extract of SE (IC50 = 724.3 ± 42.9 μg/mL) and the highest activity was demonstrated by 60% ethanol extract by UAE (IC50 = 16.2 ± 2.4 μg/mL). All extracts were analysed by GC-MS and identified metabolites like carbohydrates, fatty acids, organic acids, phenolic acids, sterols and alkane-based compounds etcetera that may possess the potential as α-glucosidase inhibitor and may attribute to the α-glucosidase inhibitory activity.
    Matched MeSH terms: Ethanol/chemistry; Solvents/chemistry; Arecaceae/chemistry; Glycoside Hydrolase Inhibitors/chemistry
  16. Schwarzinicines A-G, 1,4-Diarylbutanoid-Phenethylamine Conjugates from the Leaves of Ficus schwarzii
    Krishnan P, Lee FK, Yap VA, Low YY, Kam TS, Yong KT, et al.
    J Nat Prod, 2020 01 24;83(1):152-158.
    PMID: 31935094 DOI: 10.1021/acs.jnatprod.9b01160
    Schwarzinicines A-G (1-7), representing the first examples of 1,4-diarylbutanoid-phenethylamine conjugates, were isolated from the leaves of Ficus schwarzii. The structures of these compounds were determined by detailed analysis of their MS, 1D and 2D NMR data. Compounds 1-4 exhibited pronounced vasorelaxant effects in the rat isolated aorta (Emax 106-120%; EC50 0.96-2.10 μM). However, compounds 1 and 2 showed no cytotoxic effects against A549, MCF-7, and HCT 116 human cancer cells (IC50 > 10 μM).
    Matched MeSH terms: Antineoplastic Agents, Phytogenic/chemistry*; Phenethylamines/chemistry*; Plant Leaves/chemistry*; Ficus/chemistry*
  17. Towards an eco-friendly deconstruction of agro-industrial biomass and preparation of renewable cellulose nanomaterials: A review
    Teo HL, Wahab RA
    Int J Biol Macromol, 2020 Oct 15;161:1414-1430.
    PMID: 32791266 DOI: 10.1016/j.ijbiomac.2020.08.076
    There is an array of methodologies to prepare nanocellulose (NC) and its fibrillated form (CNF) with enhanced physicochemical characteristics. However, acids, bases or organosolv treatments on biomass are far from green, and seriously threaten the environment. Current approach to produce NC/CNF from biomass should be revised and embrace the concept of sustainability and green chemistry. Although hydrothermal process, high-pressure homogenization, ball milling technique, deep eutectic solvent treatment, enzymatic hydrolysis etc., are the current techniques for producing NC, the route designs remain imperfect. Herein, this review highlights the latest methodologies in the pre-processing and isolating of NC/CNF from lignocellulose biomass, by largely focusing on related papers published in the past two years till date. This article also explores the latest advancements in environmentally friendly NC extraction techniques that cooperatively use ball milling and enzymatic hydrolytic routes as an eco-efficient way to produce NC/CNF, alongside the potential applications of the nano-sized celluloses.
    Matched MeSH terms: Cell Wall/chemistry; Cellulose/chemistry*; Lignin/chemistry; Nanostructures/chemistry*
  18. Fulltext Influence of Sputtering Temperature of TiO2 Deposited onto Reduced Graphene Oxide Nanosheet as Efficient Photoanodes in Dye-Sensitized Solar Cells
    Low FW, Chin Hock G, Kashif M, Samsudin NA, Chau CF, Indah Utami AR, et al.
    Molecules, 2020 Oct 21;25(20).
    PMID: 33096759 DOI: 10.3390/molecules25204852
    Renewable solar energy is the key target to reduce fossil fuel consumption, minimize global warming issues, and indirectly minimizes erratic weather patterns. Herein, the authors synthesized an ultrathin reduced graphene oxide (rGO) nanosheet with ~47 nm via an improved Hummer's method. The TiO2 was deposited by RF sputtering onto an rGO nanosheet with a variation of temperature to enhance the photogenerated electron or charge carrier mobility transport for the photoanode component. The morphology, topologies, element composition, crystallinity as well as dye-sensitized solar cells' (DSSCs) performance were determined accordingly. Based on the results, FTIR spectra revealed presence of Ti-O-C bonds in every rGO-TiO2 nanocomposite samples at 800 cm-1. Besides, XRD revealed that a broad peak of anatase TiO2 was detected at ~25.4° after incorporation with the rGO. Furthermore, it was discovered that sputtering temperature of 120 °C created a desired power conversion energy (PCE) of 7.27% based on the J-V plot. Further increase of the sputtering temperature to 160 °C and 200 °C led to excessive TiO2 growth on the rGO nanosheet, thus resulting in undesirable charge recombination formed at the photoanode in the DSSC device.
    Matched MeSH terms: Coloring Agents/chemistry*; Graphite/chemistry; Titanium/chemistry; Nanoparticles/chemistry
  19. Fulltext Combined Optimization of Codon Usage and Glycine Supplementation Enhances the Extracellular Production of a β-Cyclodextrin Glycosyltransferase from Bacillus sp. NR5 UPM in Escherichia coli
    Nik-Pa NIM, Sobri MFM, Abd-Aziz S, Ibrahim MF, Kamal Bahrin E, Mohammed Alitheen NB, et al.
    Int J Mol Sci, 2020 May 30;21(11).
    PMID: 32486212 DOI: 10.3390/ijms21113919
    Two optimization strategies, codon usage modification and glycine supplementation, were adopted to improve the extracellular production of Bacillus sp. NR5 UPM β-cyclodextrin glycosyltransferase (CGT-BS) in recombinant Escherichia coli. Several rare codons were eliminated and replaced with the ones favored by E. coli cells, resulting in an increased codon adaptation index (CAI) from 0.67 to 0.78. The cultivation of the codon modified recombinant E. coli following optimization of glycine supplementation enhanced the secretion of β-CGTase activity up to 2.2-fold at 12 h of cultivation as compared to the control. β-CGTase secreted into the culture medium by the transformant reached 65.524 U/mL at post-induction temperature of 37 °C with addition of 1.2 mM glycine and induced at 2 h of cultivation. A 20.1-fold purity of the recombinant β-CGTase was obtained when purified through a combination of diafiltration and nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography. This combined strategy doubled the extracellular β-CGTase production when compared to the single approach, hence offering the potential of enhancing the expression of extracellular enzymes, particularly β-CGTase by the recombinant E. coli.
    Matched MeSH terms: Codon/chemistry*; Culture Media/chemistry; Glycine/chemistry*; Nickel/chemistry
  20. Bacterial cellulose/acrylamide pH-sensitive smart hydrogel: development, characterization, and toxicity studies in ICR mice model
    Pandey M, Mohamad N, Amin MC
    Mol Pharm, 2014 Oct 6;11(10):3596-608.
    PMID: 25157890 DOI: 10.1021/mp500337r
    The objective of this study is to synthesize and evaluate acute toxicity of the bacterial cellulose (BC)/acrylamide (Am) hydrogels as noncytotoxic and biocompatible oral drug delivery vehicles. A novel series of solubilized BC/Am hydrogels were synthesized using a microwave irradiation method. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), swelling ratio, porosity, drug release, and in vitro and in vivo biocompatibility experiments. FTIR spectra revealed that the BC crystallinity and gel fraction decreased as the NaOH concentration increased from 2% to 10% w/v, whereas the optical transparency, pH sensitivity, and porosity were enhanced with increasing alkali concentration. Theophylline was used as a model drug for drug loading and release studies. The percentage of drug released was higher at pH 7.4 compared to pH 1.5. In vitro cytotoxicity and hemolytic tests indicated that the BC/Am hydrogel is noncytotoxic and hemocompatible. Results of acute oral toxicity tests on ICR mice suggested that the hydrogels are nontoxic up to 2000 mg/kg when administered orally, as no toxic response or histopathological changes were observed in comparison to control mice. The results of this study demonstrated that the pH-sensitive smart hydrogel makes it a possible safe carrier for oral drug delivery.
    Matched MeSH terms: Cellulose/chemistry*; Drug Carriers/chemistry*; Acrylamide/chemistry*; Hydrogel/chemistry*
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