Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-072X
    Keywords: Sterols ; Fungi ; Insects ; Smittium ; Trichomycetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Desmosterol was synthesized by all but 2 of 14 isolates of the fungal genus Smittium (Harpellales) obtained from the hindguts of various Diptera larvae and grown axenically on a sterol-free medium. Also detected in some isolates of Smittium were cholesterol and ergosterol, and another, unidentified sterol with an apparent molecular ion of 470. Sterol content based on dry weight of fungal tissue was as high as 0.34%, but it was shown in one isolate that sterols vary both quantitatively and qualitatively during growth of the fungus. Two axenic cultures of the trichomycete Amoebidium parasiticum (Amoebidiales) isolated from the exoskeleton of a Cladocera contained cholesterol and ergosterol, but no desmosterol. Two soil fungi with possible phylogenetic affinities to Smittium, Linderina pennispora and Dipsacomyces acuminosporus (Kickxellales), produced cholesterol alone. The possible influence of the gut fungi on arthropod growth and development is discussed.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Investigation of derivatization of primaquine (1) with various perfluoroacylating reagents revealed that the quinoline ring portion of the drug undergoes unexpectedly facile acylation. Chemical and spectral evidence in support of the assigned structures is presented and discussed. Results of the evaluation of these new primaquine derivatives for antimalarial activity is reported.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-904X
    Keywords: antimicrobial activity ; drummondin C ; long-range COSY ; chromene ; filicinic acid ; structural units
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Drummondin C (1) is an antibiotic isolated from a bioassay-directed fractionation of Hypericum drummondii (Grev.& Hook.)T.&G. It showed significant activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and the acid-fast bacterium Mycobacterium smegmatis. Two structural units of drummondin C, the 8-acetyl-5,7-dihydroxy-2,2-dimethylchromene (6) and 5-acetyl-3-methyl-filicinic acid (9), were synthesized to determine the relative importance of the two substructure portions to the antibiotic activity of the compound. The low antimicrobial activity of 6 and 9 demonstrates the necessity of both units for the antibiotic activity of drummondin C.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Rhesus monkeys were administered primaquine diphosphate (6.0 to 10.5 mg/kg, I.V.), and plasma samples were analyzed by high performance liquid chromatography for the presence of the unchanged drug and the major metabolite , 8-(3-carboxy-l-methylpropylamino)-6-methoxyquinoline (II). Primaquine had an unusually high affinity for tissue compartments which produced a rapid initial drop in plasma concentration. Within 15 minutes, the plasma concentration of II far exceeded that of primaquine. 35 to 83 % of the primaquine dose was converted to II; moreover, metabolite II possessed much lower affinity for the tissue compartments than primaquine itself.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Primaquine, an 8-aminoquinoline antimalarial, is shown to undergo unexpectedly rapid aromatic proton exchange with the medium. At a pH less than 4, the exchange of C-5 is so fast as to be unmeasurable by proton nmr methods. At a pH of 6–6.5 the half-time for exchange is 4 to 5 minutes. This unexpectedly high rate of exchange of a carbon-proton with medium may provide an important clue to the biological activity of primaquine.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-904X
    Keywords: antimalarial ; deoxoartemisinin ; microbial ; metabolites ; mammalian ; metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Deoxoartemisinin is a semisynthetic antimalarial with potential for treatment of multiple drug resistant malaria. Metabolism studies were conducted to aid in future drug development. Methods. Microbial model systems were employed which have been shown to be good predictors of mammalian drug metabolites. Metabolism studies using rats were also performed. Results. Three microbial metabolites of deoxoartemisinin were identified (2, 3, and 4). Metabolite 3 was also found in rat plasma. HPLC/MS analyses were performed on the rat plasma using 2, 3, and 4 as standards. All metabolites were thoroughly characterized by 1H and 13C-NMR. An additional rat plasma metabolite was revealed and it was shown not to be 9α-hydroxyartemisinin. Conclusions. Deoxoartemisinin was metabolized to three microbial metabolites. Metabolism by rats showed the presence of two metabolites in the plasma, one of which was the same as the microbial metabolite.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1573-904X
    Keywords: Pithecellobium racemosum ; antifungal ; triterpene glycoside ; oleanolic acid ; Carbon-13 NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. In a continuation of our search for novel antifungal compounds from higher plants, the standard extract of the bark of Pithecellobium racemosum was found to have good activity against important AIDS-related opportunistic yeasts. Methods. The extract was subjected to bioguided fractionation using silica gel column chromatography which led to purification of triterpene glycosides. The structures of these compounds were determined by a combination of spectroscopic (IR, NMR, HRMS) and chemical methods. Results. Compound 1 is a new glycoside, 3-O[α-L-arabinopyranosyl (1 -2)][α-L arabinopyranosyl (1 -6)]2-acetoamido-2-deoxy-β-D-gluco-pyranosyl oleanolic acid and Compound 2 was identified as the known compound 3-O-[α-L-arabinopyranosyl (l-2)]α-L-arabinopyranosyl (1-6)] 2-acetamido-2-deoxy-β-D-glucopyranosyl echinocystic acid. Conclusions. Compound 1 is a new glycoside, 3-O-[α-L-arabinopyranosyl (1-2)]α-L-arabinopyranosyl (l-6)]-2-acetoamido-2-deoxy-β-D-glucopyranosyl oleanolic acid and exhibits moderate antifungal activity against T. mentogrophytes, C. albicans and S. cerevisiae with MIC values of 6.25, 12.5 and 12.5 μg/ml respectively.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Several 6-chloro-5-nitropyrimidines were synthesized, and their antifungal activity was tested. Some derivatives were equipotent or superior to amphotericin B in vitro but their relatively high toxicity in mice and their chemical instability discourage further evaluation.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-904X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Following the administration of primaquine diphosphate (20 mg/kg IP), six metabolites of primaquine were found in the bile of rats. Quantitative HPLC of the metabolites revealed that the sum of the six metabolites excreted in the bile represented a quantitative recovery of the dose of primaquine.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1573-904X
    Keywords: glycine conjugate synthesis ; glucuronide ; field screening ; carboxyprimaquine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Following the synthesis of reference standards of the primaquine metabolites, a high-performance liquid chromatographic (HPLC) analytical method for carboxyprimaquine, its glycine conjugate, and its glucuronide conjugate in urine samples was developed. After the administration of primaquine, only trace quantities of primaquine and carboxyprimaquine (each less than 1% of dose) and no significant quantity of the two conjugates of carboxyprimaquine were excreted in the urine. When carboxyprimaquine was administered, only 0.3% of the dose was excreted in the urine. When carboxyprimaquine glycinate was administered, the compound was found in the 700- to 1300-µg/ml concentration range in the urine within the first few hours. Using 14C-labeled primaquine, six new metabolites were found in the urine and partially characterized. The purported metabolites of primaquine (8-amino-6-methoxyquinoline, 5-hydroxyprimaquine, and 6-desmethyl-5-hydroxyprimaquine) were not found in the urine. A field screening test for the quantitation of primaquine metabolites in urine was also investigated. The inexpensive, but sensitive assay was found to give results that closely paralleled the more complex HPLC method and it was moderately well correlated with the total radioactivity in the urine samples.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...