HPLC resolution of the enantiomers of dihydroxyphenylalanine and selected salsolinol derivatives using sulfated beta-cyclodextrin.

D- and L-dihydroxyphenylalanine (D- and L-DOPA) and enantiomers of the tetrahydroisoquinoline alkaloids salsolinol (SAL), 1-carboxysalsolinol (1-CSAL), and cis-3-carboxysalsolinol (3-CSAL) were chromatographed using sulfated beta-cyclodextrin (S-beta-CD) as a chiral selector in mobile phases with conventional reversed-phase ODS columns. S-beta-CD is a very effective chiral selector for SAL and 3-CSAL, less effective although still useful for resolving D- and L-DOPA, and gives only meager separation of the optical isomers of 1-CSAL. Stoichiometries of the complexes which form between S-beta-CD and SAL enantiomers are 1:1. Interactions between carboxylated substances and S-beta-CD appears to be more complex. Retention of the solutes studied is characterized by favorable negative enthalpy and unfavorable negative entropy changes. Enthalpy changes outweigh entropy values.

Metabolism of acridine by rat-liver enzymes.

Metabolism of acridine by S10 fractions from control adult male Sprague-Dawley rats produces mainly 9- acridone , apparently catalyzed by aldehyde oxidase ( ED1 .2.3.1). In contrast, the predominant metabolic product produced by the corresponding S10 fraction of PCB-induced liver enzymes is a dihydrodiol (either the 2,3- or 3,4-isomer) presumably derived from an epoxide. Several minor metabolites of unknown structure are also formed. During in vitro reactions aldehyde oxidase requires neither atmospheric oxygen nor NADPH. Acridine has been reported to be mutagenic to Salmonella typhimurium, but only in the absence of PCB-induced activating enzymes. It also has been reported to produce chromosomal aberrations in cultured Chinese hamster cells both with and without enzymatic activation. While a connection between aldehyde oxidase catalysis and mutagenic action of acridine has not been established, the extensive metabolic potential of this compound implies that complete description of mutagenicity will be difficult.

High pressure liquid chromatographic method for indole in shrimp: development of method and collaborative study.

A collaborative study on the determination of indole in shrimp was conducted in which a high pressure liquid chromatographic (HPLC) method and a spectrofluorometric method were compared with the AOAC gas-liquid chromatographic (GLC) method (18.075-18.078, 13th ed.). In the HPLC method, 10 g shrimp was blended with methanol, an internal standard was added, and the extract was filtered. Indole was separated on an octadecylsilane reverse phase column, using 60% MeOH-H2O, and quantitated with a fluorescence detector (excitation 280 nm, emission 330 nm) by comparing the indole peak height with that of an internal standard, 2-methyl-indole. Recoveries at a 25 micrograms/100 g level averaged 104% with a range of 90-127%, and at a level of 35 micrograms/100 g averaged 102% with a range of 93-112%. In the spectrofluorometric method, 25 g shrimp was extracted with 2% EtOAc-hexane. After several washes, indole was partitioned into a saturated NaCl-MeOH solution and its fluorescence was measured (excitation 280 nm, emission 332 nm). Recoveries at a 25 micrograms/100 g level averaged 93% with a range of 0-255% and at a level of 35 micrograms/100 g averaged 64% with a range of 0-107%. Recoveries obtained by the AOAC-GLC method at a level of 25 micrograms/100 g averaged 96% with a range of 81-116% and at a level of 35 micrograms/100 g averaged 101% with a range of 81-119%. The coefficients of variation were 20, 10, and 64% at a 25 micrograms/100 g level for the GLC method, the HPLC method, and the spectrofluorometric method, respectively. The HPLC method was adopted as official first action for indole levels in shrimp exceeding 1 microgram/100 g.

Isoquinoline alkaloids. Inhibitory actions on cation-dependent ATP-phosphohydrolases.

Representatives of eleven different classes of isoquinoline alkaloids inhibit Na+, K+-ATPase and Mg2+-ATPase in rat brain microsomal preparations. In most cases the Na+, K+-ATPase is more sensitive than Mg2+-ATPase to inhibition by the alkaloids. The classes of alkaloids can be ranked according to potency of inhibition of Na+, K+-ATPase. Protoberberines are most effective, followed in decreasing order by benzophenanthridines, benzylisoquinolines, aporphines, tetrahydroprotoberberines, pavines, protopines, isoquinolines, tetrahydrobenzylisoquinolines, morphinanes, and tetrahydroisoquinolines. As specific representatives of each of the first four classes of alkaloids, berberine, sanguinarine, papaveroline and 1,2,10,11-tetrahydroxyaporphine, respectively, prove most valuable in kinetic studies because they exhibit the greatest inhibitory action on brain Na+, K+-ATPase. Kinetic analyses plotted in double reciprocal form reveal that berberine and 1,2,10,11-tetrahydroxyaporphine are simple linear competitive inhibitors with respect to ATP, whereas sanguinarine and papaveroline are simple linear noncompetitive inhibitors. These four representative alkaloids exhibit non-linear competitive inhibition with respect to Na+-activation. Additionally, these alkaloids significantly inhibit rat brain microsomal K+-activated pNPPase. The results demonstrate that certain members of several classes of isoquinoline alkaloids markedly affect various cation-dependent phosphohydrolases in vitro.

Disposition of catecholamine-derived alkaloids in mammalian systems.

Tetrahydropapaveroline, the tetrahydroisoquinoline alkaloid derived from dopamine, is converted in vivo by rats and by rat liver and brain preparations to tetrahydroprotoberberine alkaloids. The latter alkaloids have also been identified for the first time in the urine of parkinsonian patients receiving L-dopa therapy. These findings suggest that man, like plants, may have the ability to elaborate several classes of alkaloids with potentially important pharmacological consequences. Thus, this newly demonstrated ability of mammalian systems to evoke the biosynthesis of benzyl-tetrahydroisoquinoline-derived alkaloids - a capability previously considered unique to plants - elects the tetrahydroprotoberberine alkaloids as representative of the first class of a possible constellation of complex mammalian alkaloids elaborated from the neuroamines.