4 research outputs found
New Cytotoxic Naphthohydroquinone Dimers from <i>Rubia alata</i>
Two novel naphthohydroquinone dimers
with unprecedented skeletons,
rubialatins A (<b>1</b>) and B (<b>2</b>), were isolated
from the herbal plant <i>Rubia alata</i> together with their
precursor, mollugin (<b>3</b>). The structures were elucidated
on the basis of NMR spectra and crystal X-ray diffraction. Compound <b>1</b>, a racemate, was separated by chiral column chromatography,
and the absolute configurations of the enantiomers were determined
by the computational methods. Cytotoxicity of <b>1</b>–<b>3</b> was evaluated as well as the effect on the NF-κB pathway.
Compound (+)-<b>1</b> showed cytotoxicity and could inhibit
NF-κB pathway. Meanwhile, <b>2</b> showed cytotoxicity
and a synergistic effect with TNF-α on NF-κB activation
Key HMBC, <sup>1</sup>H-<sup>1</sup>H COSY, and ROESY correlations of 1.
<p>Key HMBC, <sup>1</sup>H-<sup>1</sup>H COSY, and ROESY correlations of 1.</p
<sup>1</sup>H NMR spectra comparison of rubipodanin A (1, top) and RA-V (4, bottom).
<p><sup>1</sup>H NMR spectra comparison of rubipodanin A (1, top) and RA-V (4, bottom).</p