Anthraquinones from the Aerial Parts of Rubia cordifolia with Their NO Inhibitory and Antibacterial Activities

Abstract

The present study aimed to identify the composition of the aerial parts of <i>Rubia cordifolia</i> L. A chemical investigation on the EtOAc extracts from the aerial parts of <i>Rubia cordifolia</i> resulted in the isolation of four new anthraquinones, namely Cordifoquinone A-D (<b>1</b>-<b>4</b>), along with 16 known anthraquinones. Their structures were elucidated on the basis of NMR and HR-ESIMS data. All isolates were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells. Compounds <b>1</b>, <b>3</b> and <b>10</b> exhibited significant inhibitory activities with IC₅₀ values of 14.05, 23.48 and 29.23 μmol·L^-1, respectively. Their antibacterial activities of four bacteria, <i>Escherichia coli</i> (ATCC 25922), <i>Staphylococcus aureus</i> subsp. <i>aureus</i> (ATCC 29213), <i>Salmonella enterica</i> subsp. <i>enterica</i> (ATCC 14028) and <i>Pseudomonas aeruginosa</i> (ATCC 27853), were also evaluated. Our results indicated that the antibacterial activity of these compounds is inactive.