The aerial parts of A. chrysocoma and A. coarctata afforded 22 and 9 sesquiterpene lactones, respectively. All the compounds described are new for the studied species. The lactones 5, 6 and 12 are new for the genus Achillea.

Nitrosation reactions of alpha-, beta-, and gamma-amino acids whose reaction products can act as alkylating agents of DNA were investigated. To approach in vivo conditions for the two-step mechanism (nitrosation and alkylation), nitrosation reactions were carried out in aqueous acid conditions (mimicking the conditions of the stomach lumen) while the alkylating potential of the nitrosation prod...

The aim of this study was to obtain new unsaturated lactones by chemical synthesis and their microbial transformations using fungal strains. Some of these strains were able to transform unsaturated lactones into different hydroxy or epoxy derivatives. Strains of Syncephalastrum racemosum and Absidia cylindrospora gave products with a hydroxy group introduced into a tertiary carbon, while the Pe...

In the search for new sources of sesquiterpene lactones, six Centaurea species have been analyzed. The activity against the fungus Cunninghamella echinulata of (+)-cnicin (1) and (+)-salonitenolide (2), isolated from the Centaurea plants, as well as that of (+)-costunolide (3), (-)-dehydrocostuslactone (4), (-)-lychnopholide (5) and (-)-eremantholide C (6), has been evaluated. Compounds 3 and 4...

Volatiles released by the marine Roseobacter clade bacterium Rugeria pomeroyi were collected by use of a closed-loop stripping headspace apparatus (CLSA) and analysed by GC-MS. Several lactones were found for which structural proposals were derived from their mass spectra and unambiguously verified by the synthesis of reference compounds. An enantioselective synthesis of two exemplary lactones ...

Abstract Background Lactones are important compounds in the field of medicine, material and chemical industry. One promising accesses to these flexible scaffolds is NAD(P) + -dependent alcohol dehydrogenases-catalyzed oxidative lactonization diols, which relies on construction an efficient regeneration system. Results In this study, a novel system combining horse liver dehydrogenase (HLADH) wit...

Several structural analogs of 4-methyl-3-hydroxyanthranilic acid (4-MHA) that had been established as substrates of the 4-MHA-activating enzyme from Streptomyces chrysomallus (Keller, U., Kleinkauf, H., and Zocher, R. (1984) Biochemistry 23, 1479-1484) were fed in short term labeling experiments to cultures of two actinomycin-producing streptomycetes. Besides inhibition of actinomycin synthesis...

The identity of the c-caprolactone products from polymerization under the influence of amines has been studied, and conclusion about alkyl oxygen fission of the lactone ring at polymerization has been made. The main kinetic features of polymerization and molecular-weight distribution change on forming poly-C-caprolactone are discussed. On the basis of these data, polymerization mechanisms for l...

The synthesis and uses of different kinds of carbohydrate-based lactones are described. This group of compounds includes aldonolactones, other related monocyclic lactones and bicyclic systems. The latter can arise from uronic acids, carboxymethyl ethers or glycosides, or from C-branched sugars.