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DOI: 10.1055/a-0879-4721
Effects of Enantiomerically Pure β-Carboline Alkaloids from Picrasma quassioides on Human Hepatoma Cells
Publication History
received 20 November 2018
revised 04 March 2019
accepted 14 March 2019
Publication Date:
11 April 2019 (online)


Abstract
Four pairs of β-carboline enantiomers (1a/1b–4a/4b), 2 β-carboline derivatives (5 – 6) with a single enantiomeric configuration, together with 2 known achiral congeners (7 – 8) were isolated from the stems of Picrasma quassioides. Their structures were elucidated on the basis of extensive spectroscopic analyses and quantum mechanical calculations. Compound 5 possesses a 4,5-seco β-carboline framework and represents the first example of this type of β-carboline alkaloids from nature. A possible biosynthetic pathway is proposed to generate the racemate 4 and the enantiomerically pure compounds 5 and 6. All isolates were screened for their cytotoxicity against hepatocellular carcinoma Hep3B and HepG2 cells, which revealed that enantiomeric compounds 4a and 4b had distinctive effects in HepG2 cells. Further investigation showed that 4b could induce apoptosis in HepG2 cells.
Key words
Picrasma quassioides - Simaroubaceae - β-carboline alkaloids - biosynthesis - cytotoxicity - enantioselectivitySupporting Information
- Supporting Information
NMR, HRESIMS, and UV spectra of compounds 1 – 6 (Figs. 1S–38S) and further detailed experimental information (Tables 1S–6S, Figs. 39S–48S) are available as Supporting Information.