A new naphthoquinone and other antibacterial constituents from the roots of Xanthium sibiricum

Abstract

Reinvestigating the chemical constituents of the roots of Xanthium sibiricum led to the isolation of a new naphthoquinone (1), together with 13 known compounds (2–14). Their structures were elucidated by using spectroscopic analyses, including HR-ESI-MS, 1D and 2D NMR, and by comparing their NMR data with those of related compounds. Compound 1 showed moderate antibacterial activity against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Staphylococcus aureus, while 6 and 12 showed stronger antibacterial activity than the positive control ciprofloxacin against E. coli, with minimum inhibitory concentration values of 0.17 and 0.35 μg/mL, respectively.

Keywords::

• Xanthium sibiricum Patr
• compositae
• chemical constituents
• antibacterial activity

Funding

This work was supported by the Foundation for the National Natural Science Foundation of China [grant number 21162009], [grant number 21202030], [grant number 31360069]; the Major Technology Project of Hainan [grant number ZDZX20100005] and the International S&T cooperation Program of China (ISTCP) [grant number 2014DFA40850].

Notes

^1. These authors contributed equally to this work.