ABSTRACT
A new alkaloid, isothalisopavine, was isolated from Thalictrum minus and shown to be 2,3,8-trimethoxy-7-hydroxyisopavine from spectral evidence. The known thalisopavine, from T. dasycarpum, is 2,3,8-trimethoxy-9-hydroxyisopavine. Isothalisopavine is the first of its class to be substituted unsymmetrically in the two aromatic rings.
Subject(s)
Alkaloids/chemistry , Alkaloids/isolation & purification , Benzylisoquinolines , Plants/chemistry , Magnetic Resonance SpectroscopyABSTRACT
Feeding experiments with (14)C-labelled reticuline have shown that reticuline is an efficient precursor of isonorargemonine, eschscholtzidine, and 4-hydroxyeschscholtzidine in Thalictrum minus (Ranunculaceae). Feeding experiments using (14)C-labelled isonorargemonine and eschscholtzidine led to the conclusion that the substitution pattern of 4-hydroxyeschscholtzidine can be formed at the pavine stage.
ABSTRACT
We evaluated the ability of a series of 3-phenylhydantoin derivatives to induce a lymphoproliferative popliteal lymph node reaction in C57B1/6 mice. 5-Aryl-3-phenylhydantoins induced a significant lymphoproliferative reaction, whereas the 5-alkyl-substituted and the unsubstituted 3-phenylhydantoins did not. 5-Alkyl-3-phenylhydantoins were unable to induce a lymphoproliferative reaction, unlike the corresponding 5-alkyl-3-phenyl-2-thiohydantoins, which have been reported to induce a significant lymphoproliferative reaction in the same strain of mice. Based on these results, we suggest that, to induce a lymphoproliferative popliteal lymph node reaction, hydantoins have to bind covalently to proteins through the N-atoms if they are activated by electrophilic groups bound to the hydantoin ring. We also suggest that 2-thiohydantoins can bind through their S-atom, whereas hydantoins cannot do so through their O-atoms.
Subject(s)
Hydantoins/pharmacology , Lymph Nodes/drug effects , Lymph Nodes/immunology , Lymphocyte Activation/drug effects , Animals , Extremities , Female , Mice , Mice, Inbred C57BL , Phenytoin/analogs & derivatives , Phenytoin/pharmacologyABSTRACT
The mechanism of 3-hydroxy epimerization of chenodeoxycholic acid by Clostridium perfringens was investigated in 3 alpha, 7 alpha-dihydroxy-[2,2,4,4-2H4]-, 3 alpha, 7 alpha-dihydroxy-[3 beta-2H]- and 3 beta, 7 alpha-dihydroxy-[3 alpha-2H]-5 beta-cholanoic acid transformations. Our findings rule out a dehydration-rehydration pathway and agree with a redox mechanism involving 3-oxochenodeoxycholic acid as intermediate.
