Open AccessTaburnaemines A–I, Cytotoxic Vobasinyl-Iboga-Type Bisindole Alkaloids from Tabernaemontana corymbosa
Author(s) -
Yu Zhang,
Yu Xi Yuan,
Masuo Goto,
Ling Li Guo,
Xiao Nian Li,
Susan L. MorrisNatschke,
Kuo Hsiung̀ Lee,
Xiao Jiang Hao
Publication year - 2018
Publication title -
journal of natural products
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.976
H-Index - 139
eISSN - 1520-6025
pISSN - 0163-3864
DOI - 10.1021/acs.jnatprod.7b00949
Subject(s) - apocynaceae , pharmacognosy , chemistry , traditional medicine , stereochemistry , botany , biology , medicine , biological activity , biochemistry , in vitro
Nineteen vobasinyl-ibogan-type bisindole alkaloids, including nine new compounds, taburnaemines A-I (1-9), were isolated from the twigs and leaves of Tabernaemontana corymbosa. The structures and absolute configurations of the new alkaloids were determined by a combination of MS, NMR, and ECD analyses. Alkaloids 1-5 contain a rare 1,3-oxazinane moiety in the vobasinyl unit, while 6 has an uncommon 1,3-oxazolidine moiety in the iboga unit. The absolute configurations of alkaloid 1 and the known alkaloid tabernaecorymbosine A (10) were confirmed by single-crystal X-ray diffraction analysis. All of the bisindole alkaloids, except 2 and 16'-decarbomethoxytabernaecorymbosine A (14), showed antiproliferative activity (IC 50 2.6-9.8 μM) against several human cancer cell lines, including A-549, MDA-MB-231, MCF-7, KB, and P-glycoprotein-overexpressing multidrug-resistant KB cells. The preliminary structure-activity relationship correlations are also discussed.