ABSTRACT
Citrulline, a key amino acid of the urea cycle, has been shown to play a regulatory role in protein and energy metabolism in mammals. We questioned whether N-carbamoyl-putrescine (NCP), the decarboxylated derivative of citrulline, could play a role in the biological properties of this amino acid. To evidence the presence of NCP in mammalian tissues, we developed a sensitive reverse-phase high-performance liquid chromatography (HPLC) with fluorimetric detection method with precolumn dansyl derivatization and solid-phase extraction for the determination of NCP together with polyamines in biological samples. Dansyl NCP was identified with a 5.85-min retention time. Linearity was obtained in a concentration range of 0.125 to 12.5 µM. Intraday and day-to-day relative coefficients of variation ranged from 8.9% to 12.3% and from 14% to 14.3%, respectively. Recovery rates in serum ranged from 75% to 83%. Thereafter, we used this method to search for the presence of NCP in serum, muscle, liver, jejunum, and ileum in rats after both short-term intraperitoneal injection and long-term oral citrulline supplementation. We failed to detect NCP in these animals. These data suggest that NCP is not a significant citrulline metabolite in rats.
Subject(s)
Chromatography, High Pressure Liquid , Chromatography, Reverse-Phase , Citrulline/metabolism , Putrescine/analogs & derivatives , Animals , Citrulline/chemistry , Dansyl Compounds/chemistry , Putrescine/analysis , Putrescine/isolation & purification , Rats , Rats, Sprague-Dawley , Solid Phase ExtractionABSTRACT
The dual specificity CDC25 phosphatases dephosphorylate two inhibitory phospho-amino acids of cyclin-dependent kinases, a major family of cell cycle regulators. CDC25 inhibitors constitute new anti-mitotic agents with potential anticancer activity. While screening through a collection of natural products derived from marine organisms for CDC25A inhibitors, we purified and identified coscinosulfate 1, a sesquiterpene sulfate from the New Caledonian sponge Coscinoderma matthewsi, along with 4. The purified compound 1 displayed significant inhibitory activity towards CDC25A (IC(50): 3 microM).
Subject(s)
Antineoplastic Agents/isolation & purification , Porifera/chemistry , Terpenes/isolation & purification , cdc25 Phosphatases/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/isolation & purification , Enzyme Inhibitors/pharmacology , Humans , Inhibitory Concentration 50 , Magnetic Resonance Spectroscopy , Molecular Structure , Recombinant Fusion Proteins/antagonists & inhibitors , Sesquiterpenes/chemistry , Sesquiterpenes/isolation & purification , Sesquiterpenes/pharmacology , Terpenes/chemistry , Terpenes/pharmacologyABSTRACT
First biosynthetic studies utilizing tetradeuterated precursors indicate that the indole glucosinolate glucobrassicin is not a precursor of the phytoalexin brassinin, and that indole-3-acetaldoxime is an efficient precursor.
Subject(s)
Brassica/chemistry , Brassica/metabolism , Glucosinolates/metabolism , Indoles/metabolism , Oximes/metabolism , Plant Extracts/biosynthesis , Plant Extracts/metabolism , Indoles/chemistry , Molecular Structure , Oximes/chemistry , Plant Leaves/chemistry , Plant Leaves/metabolism , Plant Roots/chemistry , Plant Roots/metabolism , Sesquiterpenes , Terpenes , PhytoalexinsABSTRACT
Cystodytes cf. dellechiajei collected off Djerba furnished new lipids, sphingosines 1, as inhibitors of phospholipase A2, along with inactive homologous ceramides 2. Structures were determined by spectroscopic methods and chemical transformations.
Subject(s)
Enzyme Inhibitors/pharmacology , Phospholipases A/antagonists & inhibitors , Sphingosine/pharmacology , Urochordata/chemistry , Animals , Crotalus , Enzyme Inhibitors/chemistry , Models, Chemical , Phospholipases A2 , Sphingosine/chemistry , TunisiaABSTRACT
Bioassay-guided fractionation of an extract of Holarrhena floribunda stem, has led to the isolation of the new trichothecenes, 8-dihydrotrichothecinol A (1), loukacinol A (2), and loukacinol B (3), and the known compounds, trichothecolone (4), trichothecin (5), trichothecinol A (6), rosenonolactone (7), 6beta-hydroxyrosenonolactone (8), and rosololactone (9). The structures were determined by spectral and chemical methods, and absolute configurations were established by a modified Horeau's method using HPLC. Compounds 1 and 6 exhibited significant cytotoxicity against several human tumor cell lines, whereas compound 8 showed moderate and weak antileishmanial activity toward extracellular and intracellular Leishmania donovani, respectively.
Subject(s)
Plants, Medicinal/chemistry , Trichothecenes/isolation & purification , Animals , Drug Screening Assays, Antitumor , Humans , Mice , Mice, Inbred C57BL , Molecular Structure , Spectrum Analysis , Trichothecenes/chemistry , Tumor Cells, CulturedABSTRACT
Following feeding experiments with the tetradeuterated cruciferous phytoalexins brassinin (5b) and cyclobrassinin (6b), leaves of Brassica carinata were elicited with the blackleg causing fungus Phoma lingam and incubated. Spectroscopic and HPLC analyses indicated that both brassinin (5a) and cyclobrassinin (6a) were incorporated into the cruciferous phytoalexin brassilexin (7a).
