title: Variabines A and B: new β-carboline alkaloids from the marine sponge Luffariella variabilis.
abstract: Two new β-carboline alkaloids, variabines A (1) and B (2), were isolated from the Indonesian marine sponge Luffariella variabilis. Their structures were elucidated from spectral data, and 1 was found to be a sulfonated derivative of 2. Although numerous β-carboline alkaloids have been isolated from natural sources to date, 1 is the first β-carboline derivative containing a sulfate group. Compound 2 inhibited chymotrypsin-like activity of the proteasome and Ubc13 (E2)-Uev1A interaction with IC50 values of 4 and 5 μg/mL, respectively, whereas 1 had little effect on the activity or interaction.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Sakai
authors.forename: Hikaru
authors.initials: H
authors.lastname: Kato
authors.forename: Henki
authors.initials: H
authors.lastname: Rotinsulu
authors.forename: Fitje
authors.initials: F
authors.lastname: Losung
authors.forename: Remy E P
authors.initials: RE
authors.lastname: Mangindaan
authors.forename: Nicole J
authors.initials: NJ
authors.lastname: de Voogd
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Yokosawa
authors.forename: Sachiko
authors.initials: S
authors.lastname: Tsukamoto
mesh_terms: D000470:Alkaloids / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D002243:Carbolines / Q000302:isolation & purification* / Q000494:pharmacology; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D015394:Molecular Structure; D011161:Porifera / Q000737:chemistry*; D061988:Proteasome Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000470:Alkaloids; D002243:Carbolines; D061988:Proteasome Inhibitors; D014157:Transcription Factors; C000588435:variabine A; C000588436:variabine B; C471607:UBE2N protein, human; C471624:UBE2V1 protein, human; D044763:Ubiquitin-Conjugating Enzymes