Displaying publications 1 - 20 of 73 in total

Abstract:
Sort:
  1. Fulltext A gastrointestinal transit study on amphotericin B-loaded solid lipid nanoparticles in rats
    Amekyeh H, Billa N, Yuen KH, Chin SL
    AAPS PharmSciTech, 2015 Aug;16(4):871-7.
    PMID: 25588365 DOI: 10.1208/s12249-014-0279-4
    The gastrointestinal (GI) transit behavior of and absorption from an amphotericin B (AmB) solid lipid nanoformulation (SLN) in rats was investigated. We aimed to estimate the gastric emptying time (GET) and cecal arrival time (CAT) of AmB SLN in rats as animal models. From these two parameters, an insight on the absorption window of AmB was ascertained. Three types of SLNs, AmB, paracetamol (PAR), and sulfasalazine (SSZ), were similarly formulated using beeswax/theobroma oil composite as the lipid matrix and characterized with regard to size, viscosity, density, migration propensity within agarose gel, in vitro drug release, morphology, gastrointestinal transit, and in vivo absorption. The GET and CAT were estimated indirectly using marker drugs: PAR and sulfapyridine (SP). All three types of SLNs exhibited identical properties with regard to z-average, viscosity, relative density, and propensity to migrate. PAR was absorbed rapidly from the small intestine following emptying of the SLNs giving the T50E (time for 50% absorption of PAR) to be 1.6 h. SP was absorbed after release and microbial degradation of SSZ from SLN in the colon with a lag time of 2 h post-administration, serving as the estimated cecal arrival time of the SLNs. AmB within SLN was favorably absorbed from the small intestine, albeit slowly.
    Matched MeSH terms: Lipids/chemistry*
  2. A study on large scale cultivation of Microcystis aeruginosa under open raceway pond at semi-continuous mode for biodiesel production
    Ashokkumar V, Agila E, Salam Z, Ponraj M, Din MFM, Ani FN
    Bioresour Technol, 2014 Nov;172:186-193.
    PMID: 25262427 DOI: 10.1016/j.biortech.2014.08.100
    The study explores on upstream and downstream process in Microcystis aeruginosa for biodiesel production. The alga was isolated from temple tank, acclimatized and successfully mass cultivated in open raceway pond at semi-continuous mode. A two step combined process was designed and harvested 99.3% of biomass, the daily dry biomass productivity was recorded up to 28gm(-2)day(-1). The lipid extraction was optimized and achieved 21.3%; physicochemical properties were characterized and found 11.7% of FFA, iodine value 72% and 99.2% of ester content. The lipid was transesterified by a two step simultaneous process and produced 90.1% of biodiesel; the calorific value of the biodiesel was 38.8MJ/kg. Further, the physicochemical properties of biodiesel was characterized and found to be within the limits of American ASTM D6751. Based on the areal and volumetric biomass productivity estimation, M. aeruginosa can yield 84.1 tons of dry biomass ha(-1)year(-1).
    Matched MeSH terms: Lipids/chemistry
  3. Acute and subacute toxicity profiles of thymoquinone-loaded nanostructured lipid carrier in BALB/c mice
    Ong YS, Saiful Yazan L, Ng WK, Noordin MM, Sapuan S, Foo JB, et al.
    Int J Nanomedicine, 2016 11 09;11:5905-5915.
    PMID: 27877037
    BACKGROUND: Thymoquinone (TQ), the predominant active lipophilic component in Nigella sativa seed oil, has a variety of pharmacological properties such as anticancer activities. However, translation of TQ to clinical phase is still not possible due to its hydrophobic properties. This problem can be solved by encapsulating it in nanoformulations to enhance its pharmacological properties. In our previous study, TQ has been successfully encapsulated in a nanostructured lipid carrier (hereinafter referred to as TQNLC) with excellent physiochemical properties such as high encapsulation efficiency, high drug-loading capacity, particle diameter less than 100 nm, and stability up to 2 years. In vitro studies also proved that TQNLC exhibited antiproliferative activity toward breast and cervical cancer cell lines. However, no toxicity profile related to this formulation has been reported. In this study, we determine and compare the in vivo toxicity of both TQNLC and TQ.

    MATERIALS AND METHODS: The in vivo toxicity (acute and subacute toxicity) study was carried out by oral administration of TQNLC and TQ to BALB/c mice. Animal survival, body weight, organ weight-to-body weight ratio, hematological profile, biochemistry profile, and histopathological changes were analyzed.

    RESULTS: In acute toxicity, TQ that is loaded in nanostructured lipid carrier (NLC) was found to be less toxic than pure TQ. It can be concluded that encapsulation of TQ in lipid carrier minimizes the toxicity of the compound. In the subacute toxicity study, oral administration of 100 mg/kg of TQNLC and TQ did not cause mortality to either male or female but resulted in toxicity to the liver. It is postulated that long-term consumption of TQNLC and TQ may cause toxicity to the liver but not to the extent of altering the functions of the organ. For both treatments, the no observed adverse effect level (NOAEL) was found to be 10 mg/kg/d for mice in both sexes.

    CONCLUSION: For long-term oral consumption, TQ and TQNLC at a dose of 10 mg/kg is safe in mice and does not exert any toxic effect. The results provide safety information of TQNLC, which would further help researchers in clinical use.

    Matched MeSH terms: Lipids/chemistry*
  4. Fulltext An effective ostrich oil bleaching technique using peroxide value as an indicator
    Palanisamy UD, Sivanathan M, Radhakrishnan AK, Haleagrahara N, Subramaniam T, Chiew GS
    Molecules, 2011 Jul 05;16(7):5709-19.
    PMID: 21730920 DOI: 10.3390/molecules16075709
    Ostrich oil has been used extensively in the cosmetic and pharmaceutical industries. However, rancidity causes undesirable chemical changes in flavour, colour, odour and nutritional value. Bleaching is an important process in refining ostrich oil. Bleaching refers to the removal of certain minor constituents (colour pigments, free fatty acid, peroxides, odour and non-fatty materials) from crude fats and oils to yield purified glycerides. There is a need to optimize the bleaching process of crude ostrich oil prior to its use for therapeutic purposes. The objective of our study was to establish an effective method to bleach ostrich oil using peroxide value as an indicator of refinement. In our study, we showed that natural earth clay was better than bentonite and acid-activated clay to bleach ostrich oil. It was also found that 1 hour incubation at a 150 °C was suitable to lower peroxide value by 90%. In addition, the nitrogen trap technique in the bleaching process was as effective as the continuous nitrogen flow technique and as such would be the recommended technique due to its cost effectiveness.
    Matched MeSH terms: Lipids/chemistry*
  5. An improved method for the preparations of nanostructured lipid carriers containing heat-sensitive bioactives
    Hung LC, Basri M, Tejo BA, Ismail R, Nang HL, Abu Hassan H, et al.
    Colloids Surf B Biointerfaces, 2011 Oct 1;87(1):180-6.
    PMID: 21652183 DOI: 10.1016/j.colsurfb.2011.05.019
    Heat-sensitive bioactive compounds such as β-carotene and tocols, are widely used in the pharmaceutical and cosmetic fields. Their chemical stability in delivery systems is one of the major concerns in the production of nanostructured lipid carriers (NLCs). A previously established high-temperature high-pressure homogenisation technique involved in the preparation of NLCs can cause degradation of heat-sensitive compounds. Therefore, a novel preparation process needs to be developed to minimise the degradation of heat-sensitive active compounds during the preparation of NLCs. In this work, modified methods A and B were designed to minimise the degradation of β-carotene and tocols during the production of NLCs. These methods improved the chemical stability of heat-sensitive bioactive compounds (β-carotene and tocols) significantly compared to the previously established method. The physical stability of the formulation was maintained throughout study duration.
    Matched MeSH terms: Lipids/chemistry
  6. Anesthetic Molecule Interaction of Noble Gases with Proteins and Lipids and their Effect: A Review
    Kundu SK, Chakraborty C, Yagihara S, Teoh SL, Das S
    Curr Drug Deliv, 2018;15(10):1381-1392.
    PMID: 30124152 DOI: 10.2174/1567201815666180820101255
    Surgical operations are impossible without administering proper analgesia. Advancement in the field of anesthesia has invariably resulted in the accomplishment of all surgical processes without any inconvenience. Admittedly, the use of noble gas is on the decline. The noble gases may not interact chemically with any other substance under normal temperature and pressure but they may interact with proteins and lipids. Different anesthetic molecules may stimulate either proteins or lipids in membrane. There is a connection between the anesthetic molecules and the hydrophobic region of the membrane. In the present review, we attempt to highlight the interaction between the anesthetic molecule with proteins and lipids and their effects. We sketched few noble gases and some other existing molecules such as halothane and alcohol which interacted with proteins and lipids.
    Matched MeSH terms: Lipids/chemistry*
  7. Antifungal and Mucoadhesive Properties of an Orally Administered Chitosan-Coated Amphotericin B Nanostructured Lipid Carrier (NLC)
    Ling JTS, Roberts CJ, Billa N
    AAPS PharmSciTech, 2019 Mar 05;20(3):136.
    PMID: 30838459 DOI: 10.1208/s12249-019-1346-7
    Surface-modified nanostructured lipid carriers (NLC) represent a promising mode of drug delivery used to enhance retention of drugs at absorption site. Formulated chitosan-coated amphotericin-B-loaded NLC (ChiAmp NLC) had a size of 394.4 ± 6.4 nm, encapsulation and loading efficiencies of 86.0 ± 3% and 11.0 ± 0.1% respectively. Amphotericin-B release from NLCs was biphasic with no changes in physical properties upon exposure to simulated gastrointestinal conditions. Antifungal properties of Amphotericin-B and ChiAmpB NLC were comparable but ChiAmpB NLC was twice less toxic to red blood cells and ten times safer on HT-29 cell lines. In vitro mucoadhesion data were observed ex vivo, where ChiAmpB NLC resulted in higher retention within the small intestine compared to the uncoated formulation. The data strongly offers the possibility of orally administering a non-toxic, yet effective Amphotericin-B nanoformulation for the treatment of systemic fungal infections.
    Matched MeSH terms: Lipids/chemistry*
  8. Fulltext Antileukemic effect of zerumbone-loaded nanostructured lipid carrier in WEHI-3B cell-induced murine leukemia model
    Rahman HS, Rasedee A, How CW, Zeenathul NA, Chartrand MS, Yeap SK, et al.
    Int J Nanomedicine, 2015;10:1649-66.
    PMID: 25767386 DOI: 10.2147/IJN.S67113
    Cancer nanotherapy is progressing rapidly with the introduction of many innovative drug delivery systems to replace conventional therapy. Although the antitumor activity of zerumbone (ZER) has been reported, there has been no information available on the effect of ZER-loaded nanostructured lipid carrier (NLC) (ZER-NLC) on murine leukemia cells. In this study, the in vitro and in vivo effects of ZER-NLC on murine leukemia induced with WEHI-3B cells were investigated. The results from 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, Hoechst 33342, Annexin V, cell cycle, and caspase activity assays showed that the growth of leukemia cells in vitro was inhibited by ZER-NLC. In addition, outcomes of histopathology, transmission electron microscopy, and Tdt-mediated dUTP nick-end labeling analyses revealed that the number of leukemia cells in the spleen of BALB/c leukemia mice significantly decreased after 4 weeks of oral treatment with various doses of ZER-NLC. Western blotting and reverse-transcription quantitative polymerase chain reaction assays confirmed the antileukemia effects of ZER-NLC. In conclusion, ZER-NLC was shown to induce a mitochondrial-dependent apoptotic pathway in murine leukemia. Loading of ZER in NLC did not compromise the anticancer effect of the compound, suggesting ZER-NLC as a promising and effective delivery system for treatment of cancers.
    Matched MeSH terms: Lipids/chemistry
  9. Antinociceptive, antiinflammatory and antipyretic properties of Channa striatus fillet aqueous and lipid-based extracts in rats
    Zakaria ZA, Kumar GH, Mat Jais AM, Sulaiman MR, Somchit MN
    Methods Find Exp Clin Pharmacol, 2008 Jun;30(5):355-62.
    PMID: 18806894 DOI: 10.1358/mf.2008.30.5.1186084
    The present study was carried out to elucidate the antinociceptive, antiinflammatory and antipyretic properties of the aqueous and lipid-based extracts of Channa striatus fillet in rats. The antinociceptive activity was assessed using the formalin test, and the antiinflammatory and antipyretic activities were assessed using the carrageenan-induced paw edema and brewer's yeast-induced pyrexia tests, respectively. Both types of extracts were prepared in concentrations of 10%, 50% and 100% by serial dilution in distilled water or dimethyl sulfoxide, respectively, and were administered subcutaneously 30 min prior to each test. Except for the 10% aqueous extract which exhibits activity only in the early phase, the extracts were found to exhibit significant (P < 0.05) activity in the early and late phases of the formalin test. Furthermore, the aqueous and lipid-based extracts were also found to show significant (P < 0.05) antiinflammatory activity, with the former showing a greater effect at the lowest concentration used. The lipidbased, but not the aqueous, extract was found to have significant (P < 0.05) activity in the pyrexia test. In conclusion, the present study demonstrated that C. striatus extracts possess antinociceptive, antiinflammatory and antipyretic activities.
    Matched MeSH terms: Lipids/chemistry
  10. Fulltext Antitumor and Anti-Metastatic Effects of Citral-Loaded Nanostructured Lipid Carrier in 4T1-Induced Breast Cancer Mouse Model
    Nordin N, Yeap SK, Rahman HS, Zamberi NR, Mohamad NE, Abu N, et al.
    Molecules, 2020 Jun 09;25(11).
    PMID: 32526880 DOI: 10.3390/molecules25112670
    Cancer nano-therapy has been progressing rapidly with the introduction of many novel drug delivery systems. The previous study has reported on the in vitro cytotoxicity of citral-loaded nanostructured lipid carrier (NLC-Citral) on MDA-MB-231 cells and some preliminary in vivo antitumor effects on 4T1 breast cancer cells challenged mice. However, the in vivo apoptosis induction and anti-metastatic effects of NLC-Citral have yet to be reported. In this study, the in vitro cytotoxic, anti-migration, and anti-invasion effects of NLC-Citral were tested on 4T1 breast cancer cells. In addition, the in vivo antitumor effects of oral delivery of NLC-Citral was also evaluated on BALB/c mice induced with 4T1 cells. In vitro cytotoxicity results showed that NLC-Citral and citral gave similar IC50 values on 4T1 cells. However, wound healing, migration, and invasion assays reflected better in vitro anti-metastasis potential for NLC-Citral than citral alone. Results from the in vivo study indicated that both NLC-Citral and citral have anti-tumor and anti-metastasis effects, whereby the NLC-Citral showed better efficacy than citral in all experiments. Also, the delay of tumor progression was through the suppression of the c-myc gene expression and induction of apoptosis in the tumor. In addition, the inhibition of metastasis of 4T1 cells to lung and bone marrow by the NLC-Citral and citral treatments was correlated with the downregulation of metastasis-related genes expression including MMP-9, ICAM, iNOS, and NF-kB and the angiogenesis-related proteins including G-CSF alpha, Eotaxin, bFGF, VEGF, IL-1alpha, and M-CSF in the tumor. Moreover, NLC-Citral showed greater downregulation of MMP-9, iNOS, ICAM, Eotaxin, bFGF, VEGF, and M-CSF than citral treatment in the 4T1-challenged mice, which may contribute to the better anti-metastatic effect of the encapsulated citral. This study suggests that NLC is a potential and effective delivery system for citral to target triple-negative breast cancer.
    Matched MeSH terms: Lipids/chemistry*
  11. Augmented delivery of gemcitabine in lung cancer cells exploring mannose anchored solid lipid nanoparticles
    Soni N, Soni N, Pandey H, Maheshwari R, Kesharwani P, Tekade RK
    J Colloid Interface Sci, 2016 Nov 01;481:107-16.
    PMID: 27459173 DOI: 10.1016/j.jcis.2016.07.020
    Gemcitabine (GmcH) is an effective anti-cancer agent used in the chemotherapy of lung cancer. However, the clinical applications of GmcH has been impeded primarily due to its low blood residence time, unfavorable pharmacokinetic and pharmacodynamic (PK/PD) profile, and poor penetration in the complex environment of lung cancer cells. Thus, the present study aims to formulate GmcH loaded mannosylated solid lipid nanoparticles (GmcH-SLNs) for improving its drug uptake into the lung cancer cells. GmcH-SLNs were prepared by emulsification and solvent evaporation process, and surface modification was done with mannose using ring opening technique. The cellular toxicity and cell uptake studies were performed in A549 lung adenocarcinoma cell line. The developed nanoformulation appears to be proficient in targeted delivery of GmcH with improved therapeutic effectiveness and enhanced safety.
    Matched MeSH terms: Lipids/chemistry*
  12. Fulltext Biochemical Modulation of Lipid Pathway in Microalgae Dunaliella sp. for Biodiesel Production
    Talebi AF, Tohidfar M, Mousavi Derazmahalleh SM, Sulaiman A, Baharuddin AS, Tabatabaei M
    Biomed Res Int, 2015;2015:597198.
    PMID: 26146623 DOI: 10.1155/2015/597198
    Exploitation of renewable sources of energy such as algal biodiesel could turn energy supplies problem around. Studies on a locally isolated strain of Dunaliella sp. showed that the mean lipid content in cultures enriched by 200 mg L(-1) myoinositol was raised by around 33% (1.5 times higher than the control). Similarly, higher lipid productivity values were achieved in cultures treated by 100 and 200 mg L(-1) myoinositol. Fluorometry analyses (microplate fluorescence and flow cytometry) revealed increased oil accumulation in the Nile red-stained algal samples. Moreover, it was predicted that biodiesel produced from myoinositol-treated cells possessed improved oxidative stability, cetane number, and cloud point values. From the genomic point of view, real-time analyses revealed that myoinositol negatively influenced transcript abundance of AccD gene (one of the key genes involved in lipid production pathway) due to feedback inhibition and that its positive effect must have been exerted through other genes. The findings of the current research are not to interprete that myoinositol supplementation could answer all the challenges faced in microalgal biodiesel production but instead to show that "there is a there there" for biochemical modulation strategies, which we achieved, increased algal oil quantity and enhanced resultant biodiesel quality.
    Matched MeSH terms: Lipids/chemistry
  13. Cell-Penetrating Peptides: Correlation between Peptide-Lipid Interaction and Penetration Efficiency
    Her Choong F, Keat Yap B
    Chemphyschem, 2021 03 03;22(5):493-498.
    PMID: 33377300 DOI: 10.1002/cphc.202000873
    Cell-penetrating peptides are used in the delivery of peptides and biologics, with some cell-penetrating peptides found to be more efficient than others. The exact mechanism of how they interact with the cell membrane and penetrate it, however, remains unclear. This study attempts to investigate the difference in free energy profiles of three cell-penetrating peptides (TAT, CPP1 and CPP9) with a model lipid bilayer (DOPC) using molecular dynamics pulling simulations with umbrella sampling. Potential mean force (PMF) and free energy barrier between the peptides and DOPC are determined using WHAM analysis and MM-PBSA analysis, respectively. CPP9 is found to have the smallest PMF value, followed by CPP1 and TAT, consistent with the experimental data. YDEGE peptide, however, does not give the highest PMF value, although it is a non-cell-permeable peptide. YDEGE is also found to form water pores, alongside with TAT and CPP9, suggesting that it is difficult to distinguish true water pore formation from artefacts arising from pulling simulations. On the contrary, free energy analysis of the peptide-DOPC complex at the lipid-water interface with MM-PBSA provides results consistent with experimental data with CPP9 having the least interaction with DOPC and lowest free energy barrier, followed by CPP1, TAT and YDEGE. These findings suggest that peptide-lipid interaction at the lipid-water interface has a direct correlation with the penetration efficiency of peptides across the lipid bilayer.
    Matched MeSH terms: Lipids/chemistry
  14. Characterization and cytotoxicity of nanostructured lipid carriers formulated with olive oil, hydrogenated palm oil, and polysorbate 80
    How CW, Rasedee A, Abbasalipourkabir R
    IEEE Trans Nanobioscience, 2013 Jun;12(2):72-8.
    PMID: 23268387 DOI: 10.1109/TNB.2012.2232937
    Nanostructured lipid carriers (NLC) composed of solid and liquid lipids, and surfactants are potentially good colloidal drug carriers. Before NLC can be used as drug carriers, the cytotoxicity of their components must be ascertained. The cytotoxicity of solid lipids (trilaurin, palmitin, docosanoid acid, and hydrogenated palm oil [HPO]) and surfactants (Polysorbate 20, 80, and 85) were determined on BALB/c 3T3 cells. The HPO and Polysorbate 80 were least cytotoxic and used with olive oil in the formulation of NLC. The particle size, polydispersity index, zeta potential, specific surface area, and crystallinity index of the NLC were 61.14 nm, 0.461, -25.4 mV, and 49.07 m(2) and 27.12% respectively, while the melting point was 4.3 °C lower than of HPO. Unlike in serum-free, NLC incubated in fetal bovine serum-supplemented medium did not show particle growth, suggesting that serum proteins in medium inhibit nanoparticles aggregation. The study also showed that NLC was less toxic to BALB/c 3T3 cells than Polysorbate 80. Thus, NLC with olive oil, HPO, and Polysorbate 80 as components are potentially good drug carriers with minimal cytotoxicity on normal cells.
    Matched MeSH terms: Lipids/chemistry
  15. Fulltext Combating Intracellular Pathogens with Nanohybrid-Facilitated Antibiotic Delivery
    Bose RJC, Tharmalingam N, Choi Y, Madheswaran T, Paulmurugan R, McCarthy JR, et al.
    Int J Nanomedicine, 2020;15:8437-8449.
    PMID: 33162754 DOI: 10.2147/IJN.S271850
    BACKGROUND: Lipid polymer hybrid nanoparticles (LPHNPs) have been widely investigated in drug and gene delivery as well as in medical imaging. A knowledge of lipid-based surface engineering and its effects on how the physicochemical properties of LPHNPs affect the cell-nanoparticle interactions, and consequently how it influences the cytological response, is in high demand.

    METHODS: Herein, we have engineered antibiotic-loaded (doxycycline or vancomycin) LPHNPs with cationic and zwitterionic lipids and examined the effects on their physicochemical characteristics (size and charge), antibiotic entrapment efficiency, and the in vitro intracellular bacterial killing efficiency against Mycobacterium smegmatis or Staphylococcus aureus infected macrophages.

    RESULTS: The incorporation of cationic or zwitterionic lipids in the LPHNP formulation resulted in a size reduction in LPHNPs formulations and shifted the surface charge of bare NPs towards positive or neutral values. Also observed were influences on the drug incorporation efficiency and modulation of the drug release from the biodegradable polymeric core. The therapeutic efficacy of LPHNPs loaded with vancomycin was improved as its minimum inhibitory concentration (MIC) (2 µg/mL) versus free vancomycin (4 µg/mL). Importantly, our results show a direct relationship between the cationic surface nature of LPHNPs and its intracellular bacterial killing efficiency as the cationic doxycycline or vancomycin loaded LPHNPs reduced 4 or 3 log CFU respectively versus the untreated controls.

    CONCLUSION: In our study, modulation of surface charge in the nanomaterial formulation increased macrophage uptake and intracellular bacterial killing efficiency of LPHNPs loaded with antibiotics, suggesting alternate way for optimizing their use in biomedical applications.

    Matched MeSH terms: Lipids/chemistry
  16. Fulltext Comparison of two derivatization methods for the analysis of fatty acids and trans fatty acids in bakery products using gas chromatography
    Salimon J, Omar TA, Salih N
    ScientificWorldJournal, 2014;2014:906407.
    PMID: 24719581 DOI: 10.1155/2014/906407
    Two different procedures for the methylation of fatty acids (FAs) and trans fatty acids (TFAs) in food fats were compared using gas chromatography (GC-FID). The base-catalyzed followed by an acid-catalyzed method (KOCH3/HCl) and the base-catalyzed followed by (trimethylsilyl)diazomethane (TMS-DM) method were used to prepare FA methyl esters (FAMEs) from lipids extracted from food products. In general, both methods were suitable for the determination of cis/trans FAs. The correlation coefficients (r) between the methods were relatively small (ranging from 0.86 to 0.99) and had a high level of agreement for the most abundant FAs. The significant differences (P = 0.05) can be observed for unsaturated FAs (UFAs), specifically for TFAs. The results from the KOCH3/HCl method showed the lowest recovery values (%R) and higher variation (from 84% to 112%), especially for UFAs. The TMS-DM method had higher R values, less variation (from 90% to 106%), and more balance between variation and %RSD values in intraday and interday measurements (less than 4% and 6%, resp.) than the KOCH3/HCl method, except for C12:0, C14:0, and C18:0. Nevertheless, the KOCH3/HCl method required shorter time and was less expensive than the TMS-DM method which is more convenient for an accurate and thorough analysis of rich cis/trans UFA samples.
    Matched MeSH terms: Lipids/chemistry
  17. Fulltext Conformational dynamics of dry lamellar crystals of sugar based lipids: an atomistic simulation study
    ManickamAchari V, Bryce RA, Hashim R
    PLoS One, 2014;9(6):e101110.
    PMID: 24978205 DOI: 10.1371/journal.pone.0101110
    The rational design of a glycolipid application (e.g. drug delivery) with a tailored property depends on the detailed understanding of its structure and dynamics. Because of the complexity of sugar stereochemistry, we have undertaken a simulation study on the conformational dynamics of a set of synthetic glycosides with different sugar groups and chain design, namely dodecyl β-maltoside, dodecyl β-cellobioside, dodecyl β-isomaltoside and a C12C10 branched β-maltoside under anhydrous conditions. We examined the chain structure in detail, including the chain packing, gauche/trans conformations and chain tilting. In addition, we also investigated the rotational dynamics of the headgroup and alkyl chains. Monoalkylated glycosides possess a small amount of gauche conformers (∼20%) in the hydrophobic region of the lamellar crystal (LC) phase. In contrast, the branched chain glycolipid in the fluid Lα phase has a high gauche population of up to ∼40%. Rotational diffusion analysis reveals that the carbons closest to the headgroup have the highest correlation times. Furthermore, its value depends on sugar type, where the rotational dynamics of an isomaltose was found to be 11-15% and more restrained near the sugar, possibly due to the chain disorder and partial inter-digitation compared to the other monoalkylated lipids. Intriguingly, the present simulation demonstrates the chain from the branched glycolipid bilayer has the ability to enter into the hydrophilic region. This interesting feature of the anhydrous glycolipid bilayer simulation appears to arise from a combination of lipid crowding and the amphoteric nature of the sugar headgroups.
    Matched MeSH terms: Glycolipids/chemistry; Lipids/chemistry*
  18. Consumption of repeatedly heated soy oil increases the serum parameters related to atherosclerosis in ovariectomized rats
    Adam SK, Das S, Soelaiman IN, Umar NA, Jaarin K
    Tohoku J. Exp. Med., 2008 Jul;215(3):219-26.
    PMID: 18648182
    Repeated heating of soy oil may promote lipid peroxidation. Oxidized unsaturated fatty acids may contribute to the pathogenesis of atherosclerosis, especially in estrogen-deficient states. This study was performed to explore the deleterious effects of repeatedly heated soy oil on the development of atherosclerosis using ovariectomized rats, which represent an estrogen-deficient state. Twenty-four female Sprague-Dawley rats were ovariectomized and were divided equally into four groups. The control group was fed with 2% cholesterol diet without any oil. The three treatment groups each received 2% cholesterol diet fortified with fresh, once-heated or five-times-heated (repeatedly heated) soy oil, respectively. Serum thiobarbituric acid reactive substances (TBARS), lipid profile and homocysteine levels were measured prior to ovariectomy and at the end of four months. Ovariectomized rats treated with repeatedly heated soy oil showed significant increases in lipid peroxidation and low-density lipoprotein (LDL) levels. Treatment with once-heated or repeatedly heated soy oil caused a significant increase in total cholesterol, while fresh soy oil caused significant reduction in homocysteine level as compared to other groups. Repeatedly heated soy oil caused significant increases in TBARS and LDL as compared to fresh oil. The higher level of homocysteine in the ovariectomized rats fed with repeatedly heated oil, as compared to those fed with fresh oil, also suggests the repeatedly heated oil contributes to the development of atherosclerosis. Importantly, the protective effect of the soy oil may be lost once it was being repeatedly heated. In conclusion, the consumption of repeatedly heated oil may predispose to atherosclerosis in estrogen-deficient states.
    Matched MeSH terms: Lipids/chemistry
  19. Correlating gastric emptying of amphotericin B and paracetamol solid lipid nanoparticles with changes in particle surface chemistry
    Amekyeh H, Billa N, Roberts C
    Int J Pharm, 2017 Jan 30;517(1-2):42-49.
    PMID: 27923696 DOI: 10.1016/j.ijpharm.2016.12.001
    Oral delivery of pharmaceuticals requires that they retain their physical and chemical attributes during transit within the gastrointestinal (GI) tract, for the manifestation of desired therapeutic profiles. Solid lipid nanoparticles (SLNs) are used as carriers to improve the absorption of hydrophobic drugs. In this study, we examine the stability of amphotericin B (AmB) and paracetamol (PAR) SLNs in simulated GI fluids during gastric emptying. On contact with the simulated fluids, the particles increased in size due to ingress of the dissolution media into the particles. Simulated gastric emptying revealed that the formulations had mean sizes <350nm and neutral surface charges, both of which are optimal for intestinal absorption of SLNs. There was ingress of the fluids into the SLNs, followed by diffusion of the dissolved drug, whose rate depended on the solubility of the loaded-drug in the particular medium. Time-of-flight secondary ion mass spectrometry analyses indicated that drug loading followed the core-shell model and that the AmB SLNs have a more drug-enriched core than the PAR SLNs do. The AmB SLNs are therefore a very suitable carrier of AmB for oral delivery. The stability of the SLNs in the simulated GI media indicates their suitability for oral delivery.
    Matched MeSH terms: Lipids/chemistry*
  20. Fulltext Detecting local heterogeneity and ionization ability in the head group region of different lipidic phases using modified fluorescent probes
    Abou-Zied OK, Zahid NI, Khyasudeen MF, Giera DS, Thimm JC, Hashim R
    Sci Rep, 2015;5:8699.
    PMID: 25731606 DOI: 10.1038/srep08699
    Local heterogeneity in lipid self-assembly is important for executing the cellular membrane functions. In this work, we chemically modified 2-(2'-hydroxyphenyl)benzoxazole (HBO) and attached a C8 alkyl chain in two different locations to probe the microscopic environment of four lipidic phases of dodecyl β-maltoside. The fluorescence change in HBO and the new probes (HBO-1 and HBO-2) shows that in all phases (micellar, hexagonal, cubic and lamellar) three HBO tautomeric species (solvated syn-enol, anionic, and closed syn-keto) are stable. The formation of multi tautomers reflects the heterogeneity of the lipidic phases. The results indicate that HBO and HBO-1 reside in a similar location within the head group region, whereas HBO-2 is slightly pushed away from the sugar-dominated area. The stability of the solvated syn-enol tautomer is due to the formation of a hydrogen bond between the OH group of the HBO moiety and an adjacent oxygen atom of a sugar unit. The detected HBO anions was proposed to be a consequence of this solvation effect where a hydrogen ion abstraction by the sugar units is enhanced. Our results point to a degree of local heterogeneity and ionization ability in the head group region as a consequence of the sugar amphoterism.
    Matched MeSH terms: Lipids/chemistry*
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links