Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    ISSN: 1520-6025
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1432-2048
    Schlagwort(e): Cell culture (coniferin accumulation) ; β-Coniferin ; Glucosidase ; Linum ; 5-Methoxypodophyllotoxin ; Peroxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cell suspensions of Linum flavum L. contained large amounts (2 g·l−1) of the glucoside coniferin which was accumulated endogenously up to 12.4% on a dryweight basis. Callus material contained 5.6%, while in leaves of in-vitro-grown plantlets, the origin of the callus and suspension cultures, no coniferin could be detected. Leaf, callus and suspension material were compared for metabolite accumulation and associated enzyme activities. High coniferin contents corresponded with low 5-methoxypodophyllotoxin levels. A reciprocal relationship between β-glucosidase (E.C. 3.2.1.21) activity and coniferin accumulation was found. No relationship between peroxidase (E.C. 1.11.1.7) activity and coniferin accumulation or 5-methoxypodophyllotoxin could be demonstrated. Finally, a rapid and effective isolation procedure for coniferin was developed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    ISSN: 1432-203X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    ISSN: 1432-203X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Cell suspension cultures, derived from roots of Podophyllum hexandrum Royle (Berberidaceae), accumulate podophyllotoxin. In this study the use of β-cyclodextrin in feeding the poorly water-soluble precursor coniferyl alcohol to these cultures is described. By complexation with β-cyclodextrin, a solution of 3 mM coniferyl alcohol could be fed, resulting in enhanced podophyllotoxin accumulation. The same concentration of non-complexed suspended coniferyl alcohol had only little effect on the podophyllotoxin accumulation. β-Cyclodextrin itself was proven to be non-toxic for the cells. It did not influence the podophyllotoxin content and it was not metabolized or used as a carbon source by the cells. For comparison, coniferin, the water-soluble β-D-glucoside of coniferyl alcohol, was also fed in the same concentration. The effect of coniferin on the podophyllotoxin accumulation was stronger than that of coniferyl alcohol complexed with β-cyclodextrin, but coniferin is not commercially available.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    ISSN: 1432-203X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Podophyllotoxin was produced by cell cultures derived from needles of Callitris drummondii. The needles of this conifer contained 1.56% podophyllotoxin on a dry weight basis, 32% being present in the β-glucosidic form. Trace amounts of desoxypodophyllotoxin and matairesinol were also detected. In dark-grown cell cultures, ca. 0.02 % podophyllotoxin was accumulated, 85–90 % in the β-D-glucosidic form. Moreover, traces of the lignans matairesinol, hinokinin and asarinin were detected. Illumination stimulated the endogenous production of podophyllotoxin-β-D-glucoside; contents of up to 0.11 % could be measured.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    ISSN: 1573-739X
    Schlagwort(e): Cells, cultured ; Levodopa ; Mucuna pruriens ; Selection (genetics)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Routinely grown cell suspension cultures ofMucuna pruriens L. (Fabaceae) were able to endogenously accumulate the anti-Parkinson drug L-dihydroxyphenylalanine (L-dopa) in the range between 0.2 and 2% on a dry weight (DW) basis. The green colour that developed in light-exposed cultures, appeared to be a suitable marker to select cells with an increased L-dopa biosynthesis and/or phenoloxidase activity. For this purpose, saccharose concentrations from 0 to 4% (w/v), and light intensities of 1,000 and 2,000 lux, were involved in the selection procedure. After 6 months, photomixotrophic callus cultures with a rapid growth and a high L-dopa content of 0.9% (DW) were obtained on 2% saccharose and under 1,000 lux. The cell suspensions, derived from these calli, accumulated up to 6% (DW) L-dopa, which was the highest stable content ever measured in cultures ofM. pruriens. An L-dopa yield of approximately 1.2 g/l was calculated after 6 days of growth. In contrast, compared with the standard-grown parent cell line, the phenoloxidase activity, and consequently the bioconversion capacity as measured after entrapment in calcium alginate, of these high-producing cultures was approximately threefold lower.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    ISSN: 1573-739X
    Schlagwort(e): Antimalarials ; Artemisia annua L ; Artemisinin ; Biosynthesis ; Chemistry ; Clinical trials ; Pharmacology ; Phytochemistry ; Sesquiterpenes ; Toxicology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Artemisinin, a sesquiterpene lactone endoperoxide isolated fromArtemisia annua L., and a number of its semisynthetic derivatives have shown to possess antimalarial properties. They are all eflective againstPlasmodium parasites that are resistant to the newest and commonly used antimalarial drugs. This article gives a survey of the literature dealing with artemisinin-relaled antimalarial issues that have appeared from the end of 1989 up to the beginning of 1994. A broad range of medical and pharmaceutical disciplines is covered, including phytochemical aspects like the selection of high-producing plants, analytical procedures, and plant biotechnology. Furthermore, the organic synthesis of artemisinin derivatives is discussed, as well as their mechanism of action and antimalarial activity, metabolism and pharmacokinetics, clinical studies, sideeffects and toxicology, and biological activities other than antimalarial activity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    ISSN: 1573-5044
    Schlagwort(e): antimalarial drugs ; Artemisa annua ; artemisinin ; sesquiterpene lactones ; shoot culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract From aseptically grown Artemisia annua plantlets, shoot cultures were initiated. Using different concentrations of auxine, cytokinine and sucrose, a suitable culture medium was developed, with respect to the growth of the shoots and their artemisinin accumulation. Nitrate concentration and conductivity appeared to be suitable growth parameters. The artemisinin content was measured gas chromatographically. The shoot cultures were maintained in the developed standard medium, consisting of a half concentration of MS-salts with vitamins, 0.2 mg l-1 BAP, 0.05 mg l-1 NAA and 1% sucrose. The growth of the shoots and the artemisinin content remained stable for a longer period. They showed considerable photosynthetic activity and generally contained ca. 0.08% artemisinin on a dry weight basis. The highest artemisinin content found was 0.16% in the above mentioned standard medium, but also on the same medium with 0.5% sucrose. Attempts were made to further improve the artemisinin production by varying the medium composition through addition of gibberellic acid or casein hydroly-state; by omitting plant growth regulators; by precursor feeding, i.e. mevalonic acid; by influencing the biosynthesis routing through inhibition of the sterol synthesis by miconazole, naftifine or terbinafine; by changing gene expression with 5-azacytidine or colchicine; and by elicitation, using cellulase, chitosan, glutathione or nigeran. Enhanced artemisinin production was found with 10 mg l-1 gibberellic acid, 0.5 g l-1 casein hydrolysate, 10 mg l-1 or 20 mg l-1 naftifine. Relative increases of 154%, 169%, 140% and 120% were found, respectively. Other additions caused the growth to cease and the artemisinin contents to drop.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 38 (1994), S. 103-113 
    ISSN: 1573-5044
    Schlagwort(e): Bioconversion ; catechols ; cyclodextrins ; lignans ; plant cell cultures ; solubility enhancement
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The application of cyclodextrins as precursor solubilizers in biotechnological processes, in which plant cells are involved, is new. In this paper the possibilities for cyclodextrin facilitated bioconversions by freely suspended and/or immobilized plant cells or plant enzymes are demonstrated. After complexation with β-cyclodextrin, the phenolic steroid 17β-estradiol could be ortho-hydroxylated into a catechol, mainly 4-hydroxyestradiol, by a phenoloxidase from in vitro grown cells of Mucuna pruriens. By complexation with β-cyclodextrin the solubility of the steroid increased from almost insoluble to 660 μM. In addition, by complexation with β-cyclodextrin, a solution of 3 mM coniferyl alcohol could be fed to cell cultures of Podophyllum hexandrum in order to enhance the accumulation of podophyllotoxin. Finally, the glucosylation of podophyllotoxin by cell cultures derived from Linum flavum was investigated. Four cyclodextrins: β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin and dimethyl-β-cyclodextrin were used to improve the solubility of podophyllotoxin. Dimethyl-β-cyclodextrin met our needs the best and the solubility of podophyllotoxin could be enhanced from 0.15 to 1.92 mM. Podophyllotoxin-β-d-glucoside was formed at a rate of 0.51 mmol l-1 suspension per day by the L. flavum cells growing in the presence of 1.35 mM podophyllotoxin, complexed with dimethyl-β-cyclodextrin.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 23 (1990), S. 217-224 
    ISSN: 1573-5044
    Schlagwort(e): coniferin ; lignan biosynthesis ; permeabilization ; phenylpropanoid precursors ; podophyllotoxin ; Podophyllum hexandrum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In order to improve the production of the cytotoxic lignan podophyllotoxin, seven precursors from the phenylpropanoid-routing and one related compound were fed to cell suspension cultures derived from the rhizomes of Podophyllum hexandrum Royle. These cell cultures were able to convert only coniferin into podophyllotoxin, maximally a 12.8 fold increase in content was found. Permeabilization using isopropanol, in combination with coniferin as a substrate, did not result in an extra increase in podophyllotoxin accumulation. Concentrations of isopropanol exceeding 0.5% (v/v) were found to be rather toxic for suspension growth cells of P. hexandrum. When coniferin was fed in presence of such isopropanol concentrations, β-glucosidase activity was still present, resulting in the formation of the aglucon coniferyl alcohol. In addition, podophyllotoxin was released into the medium under these permeabilization conditions. Entrapment of P. hexandrum cells in calcium-alginate as such or in combination with the feeding of biosynthetic precursors, did not improve the podophyllotoxin production. Cell-free medium from suspension cultures at later growth stages incubated with coniferin, resulted in the synthesis of the lignan pinoresinol.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...