ABSTRACT
BACKGROUND: Long-stemmed and semi-dwarf cultivars of triticale were exposed to water stress at tillering, heading and anthesis stage. Quantitative determination of free and cell wall-bound polyamines, i.e. agmatine, cadaverine, putrescine, spermidine and spermine, was supplemented with an analysis of quantitative relationships between free and cell wall-bound polyamines. RESULTS: The content of free and cell wall-bound polyamines varied depending on the development stage, both under optimal and water stress conditions. Drought-induced increase in free agmatine content was observed at all developmental stages in long-stemmed cultivar. A depletion of spermidine and putrescine was also reported in this cultivar, and spermidine was less abundant in semi-dwarf cultivar exposed to drought stress at the three analyzed developmental stages. Changes in the content of the other free polyamines did not follow a steady pattern reflecting the developmental stages. On the contrary, the content of cell wall-bound polyamines gradually increased from tillering, through heading and until anthesis period. CONCLUSION: Water stress seemed to induce a progressive decrease in the content of free polyamines and an accumulation of cell wall-bound polyamines.
Subject(s)
Agmatine/isolation & purification , Cadaverine/isolation & purification , Cell Wall/chemistry , Putrescine/isolation & purification , Spermidine/isolation & purification , Spermine/isolation & purification , Triticale/chemistry , Agmatine/metabolism , Cadaverine/metabolism , Cell Wall/metabolism , Chromatography, High Pressure Liquid , Desiccation , Droughts , Plant Cells/chemistry , Plant Cells/metabolism , Putrescine/metabolism , Spermidine/metabolism , Spermine/metabolism , Stress, Physiological , Triticale/growth & development , Triticale/metabolism , WaterSubject(s)
Agmatine/pharmacology , Harmine/analogs & derivatives , Receptors, Drug/metabolism , Agmatine/isolation & purification , Agmatine/metabolism , Animals , Harmine/pharmacology , Harmine/physiology , Humans , Imidazoles/isolation & purification , Imidazoles/pharmacology , Imidazoline Receptors , Ligands , Ribosemonophosphates/isolation & purification , Ribosemonophosphates/pharmacology , Ribosemonophosphates/physiology , Ureohydrolases/metabolismABSTRACT
The more polar metabolites from the Venezuelan plant Verbesina caracasana, i.e., N(3)-prenylagmatine, (3,4-dimethoxycinnamoyl)-N(1)-agmatine, agmatine, and galegine (prenylguanidine), previously reported (Delle Monache, G.; et al. BioMed. Chem. Lett. 1999, 9, 3249-3254), have been synthesized following a biosynthetic strategy. The pharmacologic profiles of various synthetic analogues of (3,4-dimethoxycinnamoyl)-N(1)-agmatine (G5) were also analyzed, to shed some light on the structure-activity relationship of these compounds. Derivatives with the (E)-configuration and/or with a p-methoxybenzoyl moiety were found to be responsible for higher hypotensive effects, which were associated with a slight and, in some cases, not dose-related increase of cardiac inotropism, with variable and not significant chronotopic responses, and, only at higher doses, with effects of respiratory depression. Either an increase (to six) or a decrease (to two) of the number of methylene groups in the alkyl chain of (E)-G5 did not change blood pressure responses, while slightly increasing the positive inotropic ones. At pharmacological doses, all the studied compounds showed hypotensive and slight positive inotropic effects without relevant chronotropic and respiratory actions.
Subject(s)
Agmatine/chemical synthesis , Antihypertensive Agents/chemical synthesis , Guanidines/chemical synthesis , Plants, Medicinal/chemistry , Agmatine/analogs & derivatives , Agmatine/chemistry , Agmatine/isolation & purification , Agmatine/pharmacology , Animals , Antihypertensive Agents/chemistry , Antihypertensive Agents/isolation & purification , Antihypertensive Agents/pharmacology , Blood Pressure/drug effects , Guanidines/chemistry , Guanidines/pharmacology , Heart Rate/drug effects , Male , Rats , Rats, Wistar , Stereoisomerism , Structure-Activity Relationship , VenezuelaABSTRACT
Clonidine, an antihypertensive drug, binds to alpha 2-adrenergic and imidazoline receptors. The endogenous ligand for imidazoline receptors may be a clonidine-displacing substance, a small molecule isolated from bovine brain. This clonidine-displacing substance was purified and determined by mass spectroscopy to be agmatine (decarboxylated arginine), heretofore not detected in brain. Agmatine binds to alpha 2-adrenergic and imidazoline receptors and stimulates release of catecholamines from adrenal chromaffin cells. Its biosynthetic enzyme, arginine decarboxylase, is present in brain. Agmatine, locally synthesized, is an endogenous agonist at imidazoline receptors, a noncatecholamine ligand at alpha 2-adrenergic receptors and may act as a neurotransmitter.
Subject(s)
Agmatine/metabolism , Brain Chemistry , Adrenal Medulla/drug effects , Adrenal Medulla/metabolism , Agmatine/chemistry , Agmatine/isolation & purification , Agmatine/pharmacology , Animals , Binding Sites , Brain/enzymology , Brain/metabolism , Carboxy-Lyases/metabolism , Cattle , Cerebral Cortex/metabolism , Clonidine/analogs & derivatives , Clonidine/metabolism , Epinephrine/metabolism , Imidazoline Receptors , Neurotransmitter Agents/metabolism , Norepinephrine/metabolism , Rats , Receptors, Adrenergic, alpha/metabolism , Receptors, Drug/metabolismABSTRACT
New thiol protease inhibitors, estatins A and B, were isolated from the culture filtrate of Myceliophthora thermophila M4323. The basic, water-soluble inhibitors were characterized as having an agmatine, trans-epoxysuccinic acid and L-phenylalanine or L-tyrosine moieties in the structure. The molecular formulas C18H25N5O5 and C18H25N5O6 for A and B were indicated by elemental analysis and fast atom bombardment MS. Estatins were specific inhibitors against thiol proteases such as papain, ficin and bromelain. They suppressed IgE antibody production in mice, but not IgG.
