Geology

Stereocenter

Organic chemistry

Tryptophan

Stereochemistry

Hydrolysis

Enantioselective synthesis

Catalysis

Mass spectrometry

Chemistry

Derivatization

Alkaloid

High resolution

Chromatography

Amino acid

Biochemistry

Remote sensing

Journal of Natural Products

Fruiting bodies of Mycena metata were screened for the presence of new secondary metabolites by means of HPLC-UV, LC-HR-ESIMS, and high-resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (HR-MALDI-MS imaging). Thus, a new β-carboline alkaloid, 6-hydroxymetatacarboline D (1d), was isolated from fruiting bodies of M. metata. 6-Hydroxymetatacarboline D consists of a highly substituted β-carboline skeleton, which is likely to be derived biosynthetically from l-tryptophan, 2-oxoglutaric acid, l-threonine, and l-proline. The structure of the alkaloid was established by 2D NMR spectroscopic methods and HR-ESIMS. Moreover, by extensive application of LC-HR-ESIMS, LC-HR-ESIMS/MS, and LC-HR-ESIMS3 techniques we were able to elucidate the structures of a number of accompanying β-carboline alkaloids, 1a–1c, 1e–1i, and 2a–2g, structurally closely related to 6-hydroxymetatacarboline D, which are present in M. metata in minor amounts. The absolute configuration of the stereogenic centers of the β-carboline alkaloids was determined by GC-MS comparison with authentic synthetic samples after hydrolytic cleavage and derivatization of the resulting amino acids.

HR-MALDI-MS Imaging Assisted Screening of β-Carboline Alkaloids Discovered from <i>Mycena metata</i>

HR-MALDI-MS Imaging Assisted Screening of β-Carboline Alkaloids Discovered from Mycena metata