Displaying publications 21 - 40 of 45 in total

Abstract:
Sort:
  1. Mahdi ES, Noor AM, Sakeena MH, Abdullah GZ, Abdulkarim MF, Sattar MA
    Int J Nanomedicine, 2011;6:2499-512.
    PMID: 22072884 DOI: 10.2147/IJN.S22337
    BACKGROUND: Recently there has been a remarkable surge of interest about natural products and their applications in the cosmetic industry. Topical delivery of antioxidants from natural sources is one of the approaches used to reverse signs of skin aging. The aim of this research was to develop a nanoemulsion cream for topical delivery of 30% ethanolic extract derived from local Phyllanthus urinaria (P. urinaria) for skin antiaging.

    METHODS: Palm kernel oil esters (PKOEs)-based nanoemulsions were loaded with P. urinaria extract using a spontaneous method and characterized with respect to particle size, zeta potential, and rheological properties. The release profile of the extract was evaluated using in vitro Franz diffusion cells from an artificial membrane and the antioxidant activity of the extract released was evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method.

    RESULTS: Formulation F12 consisted of wt/wt, 0.05% P. urinaria extract, 1% cetyl alcohol, 0.5% glyceryl monostearate, 12% PKOEs, and 27% Tween 80/Span 80 (9/1) with a hydrophilic lipophilic balance of 13.9, and a 59.5% phosphate buffer system at pH 7.4. Formulation F36 was comprised of 0.05% P. urinaria extract, 1% cetyl alcohol, 1% glyceryl monostearate, 14% PKOEs, 28% Tween 80/Span 80 (9/1) with a hydrophilic lipophilic balance of 13.9, and 56% phosphate buffer system at pH 7.4 with shear thinning and thixotropy. The droplet size of F12 and F36 was 30.74 nm and 35.71 nm, respectively, and their nanosizes were confirmed by transmission electron microscopy images. Thereafter, 51.30% and 51.02% of the loaded extract was released from F12 and F36 through an artificial cellulose membrane, scavenging 29.89% and 30.05% of DPPH radical activity, respectively.

    CONCLUSION: The P. urinaria extract was successfully incorporated into a PKOEs-based nanoemulsion delivery system. In vitro release of the extract from the formulations showed DPPH radical scavenging activity. These formulations can neutralize reactive oxygen species and counteract oxidative injury induced by ultraviolet radiation and thereby ameliorate skin aging.

    Matched MeSH terms: Esters/chemistry
  2. Low SY, Tan JY, Ban ZH, Siwayanan P
    J Oleo Sci, 2021 Aug 05;70(8):1027-1037.
    PMID: 34248098 DOI: 10.5650/jos.ess21078
    Liquid detergent has an increasing demand in North America, Western Europe, and Southeast Asia countries owing to its convenience to use and efficiency to clean. Alpha methyl ester sulfonates (α-MES), an anionic surfactant derived from palm oil based methyl ester, was reported to have lower manufacturing cost, good detergency with less dosage, excellent biodegradability, higher tolerance to hard water, and lower eco-toxicity as compared to linear alkylbenzene sulfonates (LABS). LABS was known as the workhorse of the detergent industry in the 20th century. Although palm-based α-MES was successfully used as the sole surfactant in powder detergent, there are still some unsettled technical issues related to phase stability and viscosity when using this anionic surfactant in heavy-duty laundry liquid detergent formulations. This paper will review not only the market overview of detergents, the application and performance of green surfactants in laundry detergents but also will highlight the technical issues related to the application of palm-based α-MES in laundry liquid detergent and some of the possible methods to overcome the formulation adversities.
    Matched MeSH terms: Esters/chemistry; Sulfuric Acid Esters/chemistry
  3. Lim SH, Lee HB, Ho AS
    Photochem Photobiol, 2011 Sep-Oct;87(5):1152-8.
    PMID: 21534974 DOI: 10.1111/j.1751-1097.2011.00939.x
    In our screening for photosensitizers from natural resources, 15(1)-hydroxypurpurin-7-lactone ethyl methyl diester (compound 1) was isolated for the first time from an Araceae plant. To evaluate the efficacy of compound 1 as a photosensitizer for head and neck cancers, compound 1 was studied in reference to a known photosensitizer pheophorbide-a (Pha), in terms of photophysical properties, singlet oxygen generation and in in vitro experiments (intracellular uptake and phototoxicity assays) in two oral (HSC2 and HSC3) and two nasopharyngeal (HK1 and C666-1) cancer cell lines. In this study, compound 1 exhibited higher intracellular uptake over 24 h compared with Pha in both HSC3 and HK1 cells. When activated by ≥4.8 J cm(-2) of light, compound 1 was slightly more potent as a photosensitizer than Pha by consistently having marginally lower IC(50) values across different cell lines. In flow cytometry experiments to study the mechanism of photoactivated cell death in HSC3, compound 1 was observed to induce more pronounced apoptosis compared with Pha, which may have been driven by the transient G(2)/M cell cycle block which was also observed. These promising results on compound 1 warrant its further investigation as a clinically useful photodynamic therapy agent for head and neck cancer.
    Matched MeSH terms: Esters/chemistry
  4. Lakshmanan S, Yung YL
    PMID: 33596165 DOI: 10.1080/19440049.2020.1842516
    Chloride reduction in crude palm oil (CPO) of greater than 80% was achieved with water washing conducted at 90°C. Inorganic chloride content in CPO was largely removed through washing, with no significant reduction in the organic chloride. Phosphorous content of CPO reduced by 20%, while trace elements such as calcium, magnesium and iron were also reduced in the washing operation. The 3-MCPDE formed in the refined, bleached and deodorised palm oil displayed (RBDPO) a linear relationship with the chloride level in washed CPO, which could be represented by the equation y = 0.91x, where y is 3-MCPDE and x represents the chloride in RBDPO refined from washed CPO. In plant scale trials using 5% water at 90°C, mild acidification of the wash water at 0.05% reduced chloride by average 76% in washed CPO. Utilising selected bleaching earths, controlled wash water temperature and wash water volume produced low chloride levels in RBDPO. Chloride content less than 1.4 mg kg-1 in plant RBDPO production was achieved, through physical refining of washed CPO containing less than 2 mg kg-1 chloride and would correspond to 3-MCPDE levels of 1.25 mg kg-1 in RBDPO. The 3-MCPDE reduced further to 1.1 mg kg-1 as the chloride level of washed CPO decreased below 1.8 mg kg-1. Chloride has been shown to facilitate the 3-MCPDE formation and its removal in lab scale washing study has yielded lower 3-MCPDE levels formed in RBDPO. In actual plant operations using washed CPO, 3-MCPDE levels below 1.25 mg kg-1 were achieved consistently in RBDPO.
    Matched MeSH terms: Esters/chemistry*
  5. Kumar CS, Then LY, Chia TS, Chandraju S, Win YF, Sulaiman SF, et al.
    Molecules, 2015 Sep 11;20(9):16566-81.
    PMID: 26378514 DOI: 10.3390/molecules200916566
    A series of five new 2-(1-benzofuran-2-yl)-2-oxoethyl 4-(un/substituted)benzoates 4(a-e), with the general formula of C₈H₅O(C=O)CH₂O(C=O)C₆H₄X, X = H, Cl, CH₃, OCH₃ or NO₂, was synthesized in high purity and good yield under mild conditions. The synthesized products 4(a-e) were characterized by FTIR, ¹H-, (13)C- and ¹H-(13)C HMQC NMR spectroscopic analysis and their 3D structures were confirmed by single-crystal X-ray diffraction studies. These compounds were screened for their antimicrobial and antioxidant activities. The tested compounds showed antimicrobial ability in the order of 4b < 4a < 4c < 4d < 4e and the highest potency with minimum inhibition concentration (MIC) value of 125 µg/mL was observed for 4e. The results of antioxidant activities revealed the highest activity for compound 4e (32.62% ± 1.34%) in diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 4d (31.01% ± 4.35%) in ferric reducing antioxidant power (FRAP) assay and 4a (27.11% ± 1.06%) in metal chelating (MC) activity.
    Matched MeSH terms: Esters/chemistry*
  6. Khayoon MS, Olutoye MA, Hameed BH
    Bioresour Technol, 2012 May;111:175-9.
    PMID: 22405756 DOI: 10.1016/j.biortech.2012.01.177
    Methyl esters were synthesized from crude karanj oil (CKO) by single step esterification with methanol using sulfuric acid (H(2)SO(4)) and phosphoric acid (H(3)PO(4)) as catalysts in a homogeneous batch process. H(3)PO(4) was less active than H(2)SO(4) during the process as it presented very low ester yields (<20%) for the various molar ratios of fatty acid to alcohol studied. With H(2)SO(4) as catalyst, the yield was as high as 89.8% at 65°C after 5h. The fatty acids profile of the oil (palmitic acid: ≈ 12%; stearic acid: ≈ 8%; oleic acid: ≈ 52% and linolenic acid of 17%) and the different reactivities of the acids were responsible for the observed differences in conversion to methyl esters. The findings attained with this study might contribute to the economic utilization of a non-edible feedstock.
    Matched MeSH terms: Esters/chemistry
  7. Khairudin N, Basri M, Fard Masoumi HR, Samson S, Ashari SE
    Molecules, 2018 Feb 13;23(2).
    PMID: 29438284 DOI: 10.3390/molecules23020397
    Azelaic acid (AzA) and its derivatives have been known to be effective in the treatment of acne and various cutaneous hyperpigmentary disorders. The esterification of azelaic acid with lauryl alcohol (LA) to produce dilaurylazelate using immobilized lipase B from Candida antarctica (Novozym 435) is reported. Response surface methodology was selected to optimize the reaction conditions. A well-fitting quadratic polynomial regression model for the acid conversion was established with regards to several parameters, including reaction time and temperature, enzyme amount, and substrate molar ratios. The regression equation obtained by the central composite design of RSM predicted that the optimal reaction conditions included a reaction time of 360 min, 0.14 g of enzyme, a reaction temperature of 46 °C, and a molar ratio of substrates of 1:4.1. The results from the model were in good agreement with the experimental data and were within the experimental range (R² of 0.9732).The inhibition zone can be seen at dilaurylazelate ester with diameter 9.0±0.1 mm activities against Staphylococcus epidermidis S273. The normal fibroblasts cell line (3T3) was used to assess the cytotoxicity activity of AzA and AzA derivative, which is dilaurylazelate ester. The comparison of the IC50 (50% inhibition of cell viability) value for AzA and AzA derivative was demonstrated. The IC50 value for AzA was 85.28 μg/mL, whereas the IC50 value for AzA derivative was more than 100 μg/mL. The 3T3 cell was still able to survive without any sign of toxicity from the AzA derivative; thus, it was proven to be non-toxic in this MTT assay when compared with AzA.
    Matched MeSH terms: Esters/chemistry*
  8. Kamil RN, Yusup S
    Bioresour Technol, 2010 Aug;101(15):5877-84.
    PMID: 20304636 DOI: 10.1016/j.biortech.2010.02.084
    A mathematical model describing chemical kinetics of transesterification of palm-based methyl esters with trimethylolpropane has been developed. The model was developed by utilizing nonlinear regression method, which is an efficient and powerful way to determine rate constants for both forward and reverse reactions. A comparison with previous study which excludes the reverse reactions was made. The model was based on the reverse mechanism of transesterification reactions and describes concentration changes of trimethylolpropane, monoesters and diesters production. The developed model was validated against data from the literature. The reaction rate constants were determined using MATLAB version 7.2 and the ratios of rate constants obtained were well in agreement with those reported in the literature. A good correlation between model simulations and experimental data was observed. It was proven that both methods were able to predict the rate constants with plausible accuracy.
    Matched MeSH terms: Esters/chemistry*
  9. Kamaruddin AH, Uzir MH, Aboul-Enein HY, Halim HN
    Chirality, 2009 Apr;21(4):449-67.
    PMID: 18655180 DOI: 10.1002/chir.20619
    This review tracks a decade of dynamic kinetic resolution developments with a biocatalytic inclination using enzymatic/microbial means for the resolution part followed by the racemization reactions either by means of enzymatic or chemocatalyst. These fast developments are due to the ability of the biocatalysts to significantly reduce the number of synthetic steps which are common for conventional synthesis. Future developments in novel reactions and products of dynamic kinetic resolutions should consider factors that are needed to be extracted at the early synthetic stage to avoid inhibition at scale-up stage have been highlighted.
    Matched MeSH terms: Esters/chemistry
  10. Juhari NH, Martens HJ, Petersen MA
    Molecules, 2021 Oct 16;26(20).
    PMID: 34684840 DOI: 10.3390/molecules26206260
    Fresh roselle are high in moisture and deteriorate easily, which makes drying important for extending shelf-life and increasing availability. This study investigated the influence of different drying methods (oven-drying, freeze-drying, vacuum-drying, and sun-drying) on the quality of roselle calyx expressed as physicochemical properties (moisture content, water activity, soluble solids, color), volatile compounds, and microstructure. Oven-drying and freeze-drying reduced moisture content most while vacuum-drying and sun-drying were not as efficient. All drying methods except sun-drying resulted in water activities low enough to ensure safety and quality. Vacuum-drying had no impact on color of the dry calyx and only small impact on color of water extract of calyx. Drying reduced terpenes, aldehydes, and esters but increased furans. This is expected to reduce fruity, floral, spicy, and green odors and increase caramel-like aroma. Sun-drying produced more ketones, alcohols, and esters. Scanning electron microscopy revealed that freeze-drying preserved the cell structure better, and freeze-dried samples resembled fresh samples most compared to other drying techniques. The study concludes that freeze-drying should be considered as a suitable drying method, especially with respect to preservation of structure.
    Matched MeSH terms: Esters/chemistry
  11. Hussain S, Ullah F, Ayaz M, Ali Shah SA, Ali Shah AU, Shah SM, et al.
    Drug Des Devel Ther, 2019;13:4195-4205.
    PMID: 31849451 DOI: 10.2147/DDDT.S228971
    Background: Cancer is one of the chronic health conditions worldwide. Various therapeutically active compounds from medicinal plants were the current focus of this research in order to uncover a treatment regimen for cancer. Anchusa arvensis (A. anchusa) (L.) M.Bieb. contains many biologically active compounds.

    Methods: In the current study, new ester 3-hydroxyoctyl -5- trans-docosenoate (compound-1) was isolated from the chloroform soluble fraction of A. anchusa using column chromatography. Using MTT assay, the anticancer effect of the compound was determined in human hepatocellular carcinoma cells (HepG-2) compared with normal epithelial cell line (Vero). DPPH and ABTS radical scavenging assays were performed to assess the antioxidant potential. The Molecular Operating Environment (MOE-2016) tool was used against tyrosine kinase.

    Results: The structure of the compound was elucidated based on IR, EI, and NMR spectroscopy technique. It exhibited a considerable cytotoxic effect against HepG-2 cell lines with IC50 value of 6.50 ± 0.70 µg/mL in comparison to positive control (doxorubicin) which showed IC50 value of 1.3±0.21 µg/mL. The compound did not show a cytotoxic effect against normal epithelial cell line (Vero). The compound also exhibited significant DPHH scavenging ability with IC50 value of 12 ± 0.80 µg/mL, whereas ascorbic acid, used as positive control, demonstrated activity with IC50 = 05 ± 0.15 µg/mL. Similarly, it showed ABTS radical scavenging ability (IC50 = 130 ± 0.20 µg/mL) compared with the value obtained for ascorbic acid (06 ± 0.85 µg/mL). In docking studies using MOE-2016 tool, it was observed that compound-1 was highly bound to tyrosine kinase by having two hydrogen bonds at the hinge region. This good bonding network by the compound might be one of the reasons for showing significant activity against this enzyme.

    Conclusion: Our findings led to the isolation of a new compound from A. anchusa which has significant cytotoxic activity against HepG-2 cell lines with marked antioxidant potential.

    Matched MeSH terms: Esters/chemistry
  12. Hoidy WH, Ahmad MB, Al-Mulla EA, Yunus WZ, Ibrahim Na
    J Oleo Sci, 2010;59(5):229-33.
    PMID: 20431238
    Difatty acyl thiourea (DFAT), which has biological activities as antibiotics and antifungal, has been synthesized from palm oil and thiourea using sodium ethoxide as catalyst. Ethyl fatty ester (EFE) and glycerol were produced as by-products. The synthesis was carried out by reflux palm oil with thiourea in ethanol. In this process, palm oil converted to about 81% pure DFAT after 11 hour and molar ratio of thiourea to palm oil was 6.0: 1 at 78 degrees C. Elemental analysis, Fourier transform iInfrared (FTIR) spectroscopy and (1)H nuclear magnetic resonance (NMR) technique were used to characterize both DFAT and EFE.
    Matched MeSH terms: Esters/chemistry
  13. Hew KS, Asis AJ, Tan TB, Yusoff MM, Lai OM, Nehdi IA, et al.
    Food Chem, 2020 Mar 01;307:125545.
    PMID: 31654951 DOI: 10.1016/j.foodchem.2019.125545
    Corresponding the high presence of 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) in refined palm oil, this paper re-evaluated degumming and bleaching processes of physical palm oil refining to reduce the amount of said contaminants. Separation-free water degumming was incorporated into the process, and this significantly (p 
    Matched MeSH terms: Esters/chemistry*
  14. Danov KD, Stanimirova RD, Kralchevsky PA, Basheva ES, Ivanova VI, Petkov JT
    J Colloid Interface Sci, 2015 Nov 1;457:307-18.
    PMID: 26196714 DOI: 10.1016/j.jcis.2015.07.020
    The interest to sulfonated methyl esters of fatty acids (SME) has been growing during the last decade, because these surfactants are considered as an environmentally friendly and renewable alternative of the linear alkyl-benzene sulfonates (LAS). Here, we present a quantitative study on the properties of aqueous SME solutions, and especially on their surface tension isotherms, critical micelle concentration (CMC) and its dependence on the concentration of added NaCl. It is demonstrated that the CMC of an ionic surfactant determined by electrical conductivity is insensitive to the presence of a small nonionic admixture, so that the CMC values determined by conductivity represent the CMC of the pure surfactant. Using SME as an example, we have demonstrated the application of a new and powerful method for determining the physicochemical parameters of the pure ionic surfactant by theoretical data analysis ("computer purification") if the used surfactant sample contains nonionic admixtures, which are present as a rule. This method involves fits of the experimental data for surface tension and conductivity by a physicochemical model based on a system of mass-balance, chemical-equilibrium and electric-double-layer equations, which allows us to determine the adsorption and micellization parameters of C12-, C14-, C16- and C18-SME, as well the fraction of nonionic admixtures (if any). Having determined these parameters, we can further predict the interfacial and micellization properties of the surfactant solutions, such as surface tension, adsorption, degree of counterion binding, and surface electric potential at every surfactant, salt and co-surfactant concentrations.
    Matched MeSH terms: Esters/chemistry*
  15. Chidan Kumar CS, Loh WS, Chandraju S, Win YF, Tan WK, Quah CK, et al.
    PLoS One, 2015;10(3):e0119440.
    PMID: 25742494 DOI: 10.1371/journal.pone.0119440
    A series of N-ethyl phthalimide esters 4(a-n) were synthesized and characterized by spectroscopic studies. Further, the molecular structure of majority of compounds were analysed by single crystal X-ray diffraction studies. The X-ray analysis revealed the importance of substituents on the crystal stability and molecular packing. All the synthesized compounds were tested for in vitro antioxidant activity by DPPH radical scavenging, FRAP and CUPRAC methods. Few of them have shown good antioxidant activity.
    Matched MeSH terms: Esters/chemistry
  16. Cheong JN, Mirhosseini H, Tan CP
    Int J Food Sci Nutr, 2010 Jun;61(4):417-24.
    PMID: 20151850 DOI: 10.3109/09637481003591574
    The main objective of the present study was to investigate the effect of polyoxyethylene sorbitan esters and sodium caseinate on physicochemical properties of palm-based functional lipid nanodispersions prepared by the emulsification-evaporation technique. The results indicated that the average droplet size increased significantly (P < 0.05) by increasing the chain length of fatty acids and also by increasing the hydrophile-lipophile balance value. Among the prepared nanodispersions, the nanoemulsion containing Polysorbate 20 showed the smallest average droplet size (202 nm) and narrowest size distribution for tocopherol-tocotrienol nanodispersions, while sodium caseinate-stabilized nanodispersions containing carotenoids had the largest average droplet size (386 nm), thus indicating a greater emulsifying role for Polysorbate 20 compared with sodium caseinate.
    Matched MeSH terms: Esters/chemistry
  17. Chen KH, Lee SY, Show PL, Hong SC, Chang YK
    J Chromatogr B Analyt Technol Biomed Life Sci, 2018 Nov 15;1100-1101:65-75.
    PMID: 30292951 DOI: 10.1016/j.jchromb.2018.09.039
    Dye-ligand affinity chromatography in a stirred fluidized bed has been developed for the rapid recovery of malate dehydrogenase (MDH) from highly turbid baker's yeast cell homogenate in a single step. The most suitable dye, namely Reactive Orange 4, in its optimal immobilized concentration of 8.78 mg/mL was immobilized onto high-density STREAMLINE matrix. To further examine optimal adsorption and elution conditions, the enzyme recovery operation was carried out using unclarified cell homogenates in stirred fluidized bed system. Aiming to develop a non-specific eluent, namely NaCl, to effectively elute the MDH adsorbed, direct recovery of MDH from highly turbid cell homogenate (50% w/v) in a stirred fluidized bed adsorption system was performed. The proposed system successfully achieved a recovery yield of 73.6% and a purification factor of 73.5 in a single step by using 0.6 M NaCl as an eluent at a high liquid velocity of 200 cm/h.
    Matched MeSH terms: Sulfuric Acid Esters/chemistry
  18. Bin Sintang MD, Danthine S, Patel AR, Rimaux T, Van De Walle D, Dewettinck K
    J Colloid Interface Sci, 2017 Oct 15;504:387-396.
    PMID: 28586736 DOI: 10.1016/j.jcis.2017.05.114
    In order to modify the self-assembly of sucrose esters (SEs) in sunflower oil, we added sunflower lecithin (SFL) as co-surfactant. It is hypothesized that SFL modifies the self-assembly of SEs by interrupting the extensive hydrogen bonding between SEs monomers. The addition of SFL into SEs induced gelation of the mixed surfactant system oleogels at all studied ratios. The 7:3 SEs:SFL combination showed enhanced rheological properties compared to the other studied ratios, which suggests better molecular ordering induced by SFL. The modifications might have been caused by interference in the hydrogen bonding, connecting the polar heads of SEs molecules in the presence of SFL. This effect was confirmed by thermal behavior and small angle X-ray diffraction (SAXD) analysis. From the crystallization and melting analyses, it was shown that the peak temperature, shape and enthalpy decreased as the SFL ratio increases. Meanwhile, the bi-component oleogels exhibited new peaks in the SAXD profile, which imply a self-assembly modification. The microscopic study through polarized and electrons revealed a change in the structure. Therefore, it can be concluded that a synergistic effect between SEs and SFL, more particularly at 7:3 ratio, towards sunflower oil structuring could be obtained. These findings shed light for greater applications of SEs as structuring and carrier agent in foods and pharmaceutical.
    Matched MeSH terms: Esters/chemistry
  19. Ashari SE, Mohamad R, Ariff A, Basri M, Salleh AB
    J Oleo Sci, 2009;58(10):503-10.
    PMID: 19745577
    Kojic acid monooleate is a fatty acid derivative of kojic acid which can be widely used as a skin whitening agent in a cosmetic applications. In avoiding any possible harmful effects from chemically synthesized product, the enzymatic synthesis appears to be the best way to satisfy the consumer demand nowadays. The ability of immobilized lipase from Rhizomucor meihei (lipozyme RMIM) to catalyze the direct esterification of kojic acid and oleic acid was investigated. Response Surface Methodology (RSM) and 5-level-4-factor central composite rotatable were employed to evaluate the effects of synthesis parameters such as enzyme amount (0.1-0.4 g), temperature (30-60 degrees C), substrate molar ratio (1-4 mmol, kojic acid:oleic acid) and reaction time (24-48 h) on percentage molar conversion to kojic acid monooleate. Analysis of the product using TLC, GC and FTIR showed the presence of kojic acid monooleate. The optimal conditions for the enzymatic reaction were obtained after analysis with backward elimination using 0.17 g of enzyme and 4 mmol of substrate at 52.50 degrees C for 42 h. Under these conditions the esterification percentage was 37.21%. The results demonstrated that response surface methodology can be applied effectively to optimize the lipase-catalysed synthesis of kojic acid monooleate. The optimum conditions can be used to scale up the process.
    Matched MeSH terms: Esters/chemistry
  20. 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: Esters/chemistry
Filters
Contact Us

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

External Links