Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5555179 | Fitoterapia | 2017 | 8 Pages |
Four new alkaloids, comprising three 3-oxo-3,7-seco-oxindole alkaloids (hirsutanine D-F, 1-3) and one oxindole alkaloid N-oxide (uncarine B N-oxide, 4), together with four known heteroyohimbine-type oxindole alkaloids, were isolated from the stems of Uncaria hirsuta Havil. Structures of 1-4 were elucidated by extensive NMR and HR-ESIMS data analyses. Compound 3 is the first 3-oxo-3,7-seco-oxindole alkaloid with ring B opened and degraded isolated from the Uncaria genus. Compounds 1-3 exhibited slight inhibition effect on the proliferation of the breast cancer cell MDA-MB-231. The positive mode collision-induced dissociation of the 3-oxo-3,7-seco-oxindole alkaloids (1-3) was featured by the β-cleavage and α-cleavage of the amido bond, while the N-oxide (4) showed characteristic neutral eliminations of ·OH and H2O.
Graphical abstractDownload high-res image (220KB)Download full-size image