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Jureczko M, Przystaś W, Krawczyk T, Gonciarz W, Rudnicka K. White-rot fungi-mediated biodegradation of cytostatic drugs - bleomycin and vincristine. JOURNAL OF HAZARDOUS MATERIALS 2021; 407:124632. [PMID: 33359974 DOI: 10.1016/j.jhazmat.2020.124632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/04/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
The contamination of the environment with anticancer drugs, which show recalcitrance to conventional wastewater treatment, has become a significant ecological threat. Fungi represent a promising non-conventional biological alternative for water conditioning. The aim of this work was to evaluate the efficacy of five white-rot fungi (Fomes fomentarius (CB13), Hypholoma fasciculare (CB15), Phyllotopsis nidulans (CB14), Pleurotus ostreatus (BWPH) and Trametes versicolor (CB8)) in the removal of bleomycin and vincristine. The removal capacity was measured at 0, 4, 9, and 14 days of incubation using SPE-UPLC-MS. The enzymatic profiles of laccase, manganese, and lignin peroxidases and wide range of eco- and cytotoxicity, assays of the post-process samples were also conducted. We observed >94% vincristine elimination by F. fomentarius, H. fasciculare and T. versicolor after only 4 days. Bleomycin removal occurred after a minimum of 9 days and only when the drug was incubated with T. versicolor (36%) and H. fasciculare (25%). The removal of both cytostatics was associated with laccase production, and the loss of eco- and cytotoxicity, especially in regard to viability of Lemna minor and Daphnia magna, as well as fibroblasts morphology.
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Affiliation(s)
- Marcelina Jureczko
- Environmental Biotechnology Department, Faculty of Energy and Environmental Engineering, The Silesian University of Technology, Akademicka 2, 44-100 Gliwice, Poland.
| | - Wioletta Przystaś
- Environmental Biotechnology Department, Faculty of Energy and Environmental Engineering, The Silesian University of Technology, Akademicka 2, 44-100 Gliwice, Poland; The Biotechnology Centre, The Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland.
| | - Tomasz Krawczyk
- Department of Chemical Organic Technology and Petrochemistry, Faculty of Chemistry, Silesian University of Technology, Krzywoustego 4, 44-100 Gliwice, Poland.
| | - Weronika Gonciarz
- Department of Immunology and Infectious Biology, Institute of Microbiology, Biotechnology and Immunology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Łódź, Poland.
| | - Karolina Rudnicka
- Department of Immunology and Infectious Biology, Institute of Microbiology, Biotechnology and Immunology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Łódź, Poland.
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Kosjek T, Negreira N, Heath E, López de Alda M, Barceló D. Aerobic activated sludge transformation of vincristine and identification of the transformation products. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 610-611:892-904. [PMID: 28830049 DOI: 10.1016/j.scitotenv.2017.08.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/06/2017] [Accepted: 08/07/2017] [Indexed: 06/07/2023]
Abstract
This study aims to identify (bio)transformation products of vincristine, a plant alkaloid chemotherapy drug. A batch biotransformation experiment was set-up using activated sludge at two concentration levels with and without the addition of a carbon source. Sample analysis was performed on an ultra-high performance liquid chromatograph coupled to a high-resolution hybrid quadrupole-Orbitrap tandem mass spectrometer. To identify molecular ions of vincristine transformation products and to propose molecular and chemical structures, we performed data-dependent acquisition experiments combining full-scan mass spectrometry data with product ion spectra. In addition, the use of non-commercial detection and prediction algorithms such as MZmine 2 and EAWAG-BBD Pathway Prediction System, was proven to be proficient for screening for transformation products in complex wastewater matrix total ion chromatograms. In this study eleven vincristine transformation products were detected, nine of which were tentatively identified.
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Affiliation(s)
- Tina Kosjek
- Jožef Stefan Institute, Department of Environmental Sciences, Jamova 39, Ljubljana, Slovenia.
| | - Noelia Negreira
- Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain
| | - Ester Heath
- Jožef Stefan Institute, Department of Environmental Sciences, Jamova 39, Ljubljana, Slovenia
| | - Miren López de Alda
- Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain
| | - Damià Barceló
- Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain; Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona, Spain
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Vincristine-loaded liposomes prepared by ion-paring techniques: Effect of lipid, pH and antioxidant on chemical stability. Eur J Pharm Sci 2017; 111:104-112. [PMID: 28964951 DOI: 10.1016/j.ejps.2017.09.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/17/2017] [Accepted: 09/26/2017] [Indexed: 11/20/2022]
Abstract
In the present study, vincristine (VCR)-loaded liposomes were designed by ion-pairing techniques and the model could be applied to investigate the effect of lipids on the degradation of vinca alkaloids, and how to weaken their influence by adjusting pH and adding antioxidants. It was found that there was a positive correlation between degree of degradation and the unsaturation extent of the phospholipids. In the phospholipid with the lowest oxidation index, only 6% of VCR was degraded in 6days at 37°C, whereas for the phospholipids with highest oxidation index, the degradation reached above 95% over the same time. At pH6.8 and 7.4, the degradation rate of VCR in the lipid membrane was significantly faster than that in aqueous solution, instead, at pH5.0. After the addition of butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tocopherol, ascorbate and tocopherol with ascorbate, the residual content of VCR after 6days was 79.9%, 78.1%, 7.1%, 89.6% and 94.6% respectively. It was speculated that VCR could be oxidized by hydrated peroxyl radicals, which formed from lipid peroxidation as well as nucleophilic substitution with peroxyl radicals in the dry state. Also, the antioxidants were shown to have different eliminating capacity on the peroxyl radicals whether hydrated or not, and the phenoxyl radicals generated from fat-soluble antioxidants may be potentially destabilizing to VCR. Therefore, for these two crucial reasons, the degradation of VCR was quite different when used with a combination of water and fat-soluble antioxidants, and thus provides the best protection for VCR.
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Keglevich P, Ábrányi-Balogh P, Szigetvári Á, Szántay C, Szántay C, Hazai L. Studies on the mechanism of quaternization of the catharanthine part of vinblastine and vincristine. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Bolleddula J, Chowdhury SK. Carbon-carbon bond cleavage and formation reactions in drug metabolism and the role of metabolic enzymes. Drug Metab Rev 2015; 47:534-57. [PMID: 26390887 DOI: 10.3109/03602532.2015.1086781] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Elimination of xenobiotics from the human body is often facilitated by a transformation to highly water soluble and more ionizable molecules. In general, oxidation-reduction, hydrolysis, and conjugation reactions are common biotransformation reactions that are catalyzed by various metabolic enzymes including cytochrome P450s (CYPs), non-CYPs, and conjugative enzymes. Although carbon-carbon (C-C) bond formation and cleavage reactions are known to exist in plant secondary metabolism, these reactions are relatively rare in mammalian metabolism and are considered exceptions. However, various reactions such as demethylation, dealkylation, dearylation, reduction of alkyl chain, ring expansion, ring contraction, oxidative elimination of a nitrile through C-C bond cleavage, and dimerization, and glucuronidation through C-C bond formation have been reported for drug molecules. Carbon-carbon bond cleavage reactions for drug molecules are primarily catalyzed by CYP enzymes, dimerization is mediated by peroxidases, and C-glucuronidation is catalyzed by UGT1A9. This review provides an overview of C-C bond cleavage and formation reactions in drug metabolism and the metabolic enzymes associated with these reactions.
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Affiliation(s)
- Jayaprakasam Bolleddula
- a Department of Drug Metabolism and Pharmacokinetics , Takeda Pharmaceuticals International Co. , Cambridge , MA , USA
| | - Swapan K Chowdhury
- a Department of Drug Metabolism and Pharmacokinetics , Takeda Pharmaceuticals International Co. , Cambridge , MA , USA
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Szántay C, Keglevich P, Hazai L, Dubrovay Z, Szántay C, Kalaus G. Bisindole Alkaloids Condensed with a Cyclopropane Ring, Part 1. 14,15-Cyclopropanovinblastine and -vincristine. HETEROCYCLES 2014. [DOI: 10.3987/com-13-12918] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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NMR and mass spectrometric characterization of vinblastine, vincristine and some new related impurities—Part II. J Pharm Biomed Anal 2013. [DOI: 10.1016/j.jpba.2012.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Structure elucidation of indole–indoline type alkaloids: A retrospective account from the point of view of current NMR and MS technology. J Pharm Biomed Anal 2012; 69:106-24. [DOI: 10.1016/j.jpba.2012.02.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 02/14/2012] [Accepted: 02/15/2012] [Indexed: 11/23/2022]
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9
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Dubrovay Z, Háda V, Béni Z, Szántay C. NMR and mass spectrometric characterization of vinblastine, vincristine and some new related impurities - part I. J Pharm Biomed Anal 2012; 84:293-308. [PMID: 22985529 DOI: 10.1016/j.jpba.2012.08.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 08/07/2012] [Accepted: 08/14/2012] [Indexed: 10/28/2022]
Abstract
In the course of exploring the possibilities of developing a new, improved process at Gedeon Richter for the production of the "bisindole" alkaloids vinblastine (VLB) and vincristine (VCR), some novel VLB/VCR-related trace impurities were detected by analytical HPLC. Following isolation by preparative HPLC, a combination of 1D and 2D ultra high-field NMR and high-resolution (HR) (LC-)MS/MS studies allowed the structural identification and complete spectral characterization of several hitherto unpublished VLB/VCR-analogue impurities. Since the impurities could not be isolated in entirely pure forms and were available only in minute, mass-limited quantities, accessing the spectral information needed for their ab initio structure determination was met with various practical difficulties. Successful structure determination therefore relied heavily on the availability and use of detailed and definitive spectral data for both VLB and VCR. In particular, the utilization of detailed (1)H, (13)C, and (15)N NMR assignments as well as (1)H-(1)H, (1)H-(13)C and (1)H-(15)N spin-spin connectivities pertaining to different solvents for VLB/VCR base and sulphate salt was required. Although NMR studies on VLB base and other bisindoles were reported earlier in the literature, an NMR characterization of VLB and VCR under the above-mentioned circumstances and using ultra-high field instrumentation is either scarcely available or entirely lacking, therefore the necessary data had to be obtained in-house. Likewise, a modern tandem HR-ESI-MS/MS(n) fragmentation study of VLB and VCR has not been published yet. In the present paper we therefore give a thorough NMR and MS characterization of VLB and VCR specifically with a view to filling this void and to provide sufficiently extensive and solid reference data for the structural investigation of the aforementioned VLB/VCR impurities. Besides being scientifically relevant in its own right, the disclosed data should be useful for anyone interested in VLB/VCR-related molecules at a structural level.
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Affiliation(s)
- Zsófia Dubrovay
- Chemical Works of Gedeon Richter Plc., API Research and Development - Spectroscopic Research, Budapest, Hungary
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Keglevich P, Hazai L, Kalaus G, Szántay C. Modifications on the basic skeletons of vinblastine and vincristine. Molecules 2012; 17:5893-914. [PMID: 22609781 PMCID: PMC6268133 DOI: 10.3390/molecules17055893] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/09/2012] [Accepted: 05/10/2012] [Indexed: 11/18/2022] Open
Abstract
The synthetic investigation of biologically active natural compounds serves two main purposes: (i) the total synthesis of alkaloids and their analogues; (ii) modification of the structures for producing more selective, more effective, or less toxic derivatives. In the chemistry of dimeric Vinca alkaloids enormous efforts have been directed towards synthesizing new derivatives of the antitumor agents vinblastine and vincristine so as to obtain novel compounds with improved therapeutic properties.
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Affiliation(s)
| | | | | | - Csaba Szántay
- Author to whom correspondence should be addressed; ; Tel: +36-1-463-1195; Fax: +36-1-463-3297
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Wu Y, Zhou J, Fishkin N, Rittmann BE, Sparrow JR. Enzymatic degradation of A2E, a retinal pigment epithelial lipofuscin bisretinoid. J Am Chem Soc 2011; 133:849-57. [PMID: 21166406 DOI: 10.1021/ja107195u] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Some forms of blinding macular disease are associated with excessive accumulation of bisretinoid lipofuscin in retinal pigment epithelial (RPE) cells of the eye. This material is refractory to lysosomal enzyme degradation. In addition to gene and drug-based therapies, treatments that reverse the accumulation of bisretinoid would be beneficial. Thus, we have examined the feasibility of degrading the bisretinoids by delivery of exogenous enzyme. As proof of principle we report that horseradish peroxidase (HRP) can cleave the RPE bisretinoid A2E. In both cell-free and cell-based assays, A2E levels were decreased in the presence of HRP. HRP-associated cleavage products were detected by ultraperformance liquid chromatography (UPLC) coupled to electrospray ionization mass spectrometry, and the structures of the aldehyde-bearing cleavage products were elucidated by 18O-labeling and 1H NMR spectroscopy and by recording UV−vis absorbance spectra. These findings indicate that RPE bisretinoids such as A2E can be degraded by appropriate enzyme activities.
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Affiliation(s)
- Yalin Wu
- Department of Ophthalmology, Columbia University, 630 West 168th Street, New York, New York 10032, United States
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Dennison JB, Kulanthaivel P, Barbuch RJ, Renbarger JL, Ehlhardt WJ, Hall SD. SELECTIVE METABOLISM OF VINCRISTINE IN VITRO BY CYP3A5. Drug Metab Dispos 2006; 34:1317-27. [PMID: 16679390 DOI: 10.1124/dmd.106.009902] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Clinical outcomes of vincristine therapy, both neurotoxicity and efficacy, are unpredictable, and the reported pharmacokinetics of vincristine have considerable interindividual variability. In vitro and in vivo data support a dominant role for CYP3A enzymes in the elimination of vincristine. Consequently, genetic polymorphisms in cytochrome P450 (P450) expression may contribute to the interindividual variability in clinical response, but the contributions of individual P450s and the primary pathways of vincristine metabolism have not been defined. In the present study, vincristine was incubated with a library of cDNA-expressed P450s, and the major oxidative metabolites were identified. CYP3A4 and CYP3A5 were the only P450s to support substantial loss of parent drug and formation of the previously unidentified, major metabolite (M1). The structure of M1, arising as a result of an oxidative cleavage of the piperidine ring of the dihydro-hydroxycatharanthine unit of vincristine, was conclusively established after conversion to suitable derivatives followed by spectroscopic analysis, and a new pathway for vincristine metabolism is proposed. CYP3A5 was more efficient in catalyzing the formation of M1 compared with CYP3A4 (9- to 14-fold higher intrinsic clearance for CYP3A5). The formation of M1 was stimulated (3-fold) by the presence of coexpressed cytochrome b5, but the relative efficiencies of M1 formation by CYP3A4 and CYP3A5 were unaffected. Our findings demonstrate that in contrast to most CYP3A biotransformations, the oxidation of vincristine is considerably more efficient with CYP3A5 than with CYP3A4. We conclude that common genetic polymorphisms in CYP3A5 expression may contribute to the interindividual variability in the systemic elimination of vincristine.
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Affiliation(s)
- Jennifer B Dennison
- Indiana University School of Medicine, Division of Clinical Pharmacology, 1001 West 10th St., W7123, Indianapolis, IN 46202,USA
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Affiliation(s)
- Toh-Seok Kam
- Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
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14
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Groninger E, Proost JH, de Graaf SSN. Pharmacokinetic studies in children with cancer. Crit Rev Oncol Hematol 2005; 52:173-97. [PMID: 15582785 DOI: 10.1016/j.critrevonc.2004.08.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2004] [Indexed: 11/23/2022] Open
Abstract
We reviewed the current status of our knowledge of pharmacokinetics and pharmacodynamics of some anti-neoplastic drugs, used in the treatment of childhood cancer. Extrapolation of data from pharmacokinetic studies in adults to the paediatric population is often not feasible. Specific studies in children are needed. Of all reviewed anti-neoplastic drugs methotrexate appears to be most extensively studied. Methotrexate pharmacokinetics is correlated with toxicity and response to therapy, and it has been shown that individualized adaptive dosing of methotrexate is correlated with a better response to therapy without increasing toxicity in children with ALL and osteosarcoma. Of most of the other reviewed anti-neoplastic drugs it is demonstrated that pharmacokinetics is correlated with toxicity, and of some drugs a relationship of pharmacokinetics with response to therapy is demonstrated as well. In case of cytarabine, etoposide, and teniposide, individualized dosing also appears to be feasible. However, there is no evidence that this strategy improves response to therapy. Specifically data on pharmacokinetic and pharmacodynamic correlations and effect of pharmacokinetically guided, individualized dosing are important for the design of optimal cancer chemotherapy for individual patients. Unfortunately for a considerable number of anti-neoplastic drugs these specific data are lacking in children and future research is needed.
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Affiliation(s)
- E Groninger
- Department of Paediatric Oncology Haematology, Beatrix Children's Hospital, Groningen, PO Box 30001, 9700 RB Groningen, The Netherlands.
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Rathbone DA, Lister DL, Bruce NC. Biotransformation of alkaloids. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2003; 58:1-82. [PMID: 12534248 DOI: 10.1016/s0099-9598(02)58002-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biotransformations of alkaloids over the last decade have continued to encompass a wide variety of substrates and enzymes. The elucidation of novel alkaloid biosynthetic and catabolic pathways will continue to furnish new biocatalysts for the synthetic organic chemist. Furthermore, an improved understanding of the genetic and biochemical basis of metabolic pathways will also permit the engineering of pathways in plants and other heterologous hosts for the production of therapeutically important alkaloids. The combination of increasing commercial interest and advances in molecular biology will facilitate the availability of robust biocatalysts which are a prerequsite to achieve economically feasible processes for the production of alkaloid-based therapeutics.
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Affiliation(s)
- Deborah A Rathbone
- Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, United Kingdom
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Rathbone DA, Lister DL, Bruce NC. Biotransformation of alkaloids. THE ALKALOIDS. CHEMISTRY AND BIOLOGY 2002; 57:1-74. [PMID: 11705120 DOI: 10.1016/s0099-9598(01)57002-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Biotransformations of alkaloids over the last decade have continued to encompass a wide variety of substrates and enzymes. The elucidation of novel alkaloid biosynthetic and catabolic pathways will continue to furnish new biocatalysts for the synthetic organic chemist. Furthermore, an improved understanding of the genetic and biochemical basis of metabolic pathways will also permit the engineering of pathways in plants and other heterologous hosts for the production of therapeutically important alkaloids. The combination of increasing commercial interest and advances in molecular biology will facilitate the availability of robust biocatalysts which are a prerequsite to achieve economically feasible processes for the production of alkaloid-based therapeutics.
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Affiliation(s)
- D A Rathbone
- Institute of Biotechnology, University of Cambridge, Cambridge, CB2 1QT, United Kingdom
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Plant peroxidases: Versatile catalysts in the synthesis of bioactive natural products. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1572-5995(02)80047-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Zheleva A, Michelot D, Zhelev ZD. Sensitivity of alpha-amanitin to oxidation by a lactoperoxidase-hydrogen peroxide system. Toxicon 2000; 38:1055-63. [PMID: 10708797 DOI: 10.1016/s0041-0101(99)00217-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Oxidation of alpha-amanitin - a potent hepatotoxin found in the mushroom Amanita phalloides - by a lactoperoxidase-hydrogen peroxide system was investigated by different techniques. (i). UV spectroscopy of the mixture after 24 h incubation reveals a significant decrease in the absorbance range characteristic of the putative reactive moiety of the toxin, the tryptathionine group. (ii). Formation of a new product was detected by Thin Layer Chromatography. (iii). In vivo experiments with non-inbred male albino mice showed a lowered toxicity of the modified toxin in comparison with that of the native one. Taking into account the latter results concerning the sensitivity of the toxin towards an oxidising system, the formation and reactivity of an alpha-amanitin derivative is discussed in the course of A. phalloides poisoning (inhibition of RNA polymerase type II and development of damaging radical species).
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Affiliation(s)
- A Zheleva
- Department of Chemistry and Biochemistry, Medical Faculty, Thracian University, 11 Armeiska Str. 6000, Stara Zagora, Bulgaria
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Abstract
Although the biocatalytic activation of carbon-hydrogen bonds by oxidation to alcohols was one of the first biotransformations to be exploited by the chemical industry, this remarkable process continues to be the subject of intense research activity. Recent developments in this area have centred on the use of new biocatalysts and substrates for C-H activation, in particular on the use of recombinant strains of yeast and bacteria expressing useful hydroxylase enzymes, on mechanistic work using hydroxylase enzymes that relies on the tools of molecular biology to address outstanding questions, particularly those of substrate selection and product predictability, and on the application of these systems for hydroxylation and heteroatom dealkylation reactions.
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Affiliation(s)
- H L Holland
- Department of Chemistry, Brock University, Saint Catharines Ontario L2S3A1, Canada.
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