Four previously undescribed naphthohydroquinone dimers named rubipodanones AD, together with 19 known quinones containing three known napthohydroquinone dimers named rubioncolin C, methyl 5-hydroxy-dinaphtho[1,2-2'',3'']furan-7,12-dione-6-carboxylate and rubialatin B, were isolated from the roots and rhizomes of Rubia podantha. Their structures and absolute configurations were determined mainly by NMR, X-ray diffraction, and computational methods. Rubipodanones C and D, the glycosides of rubipodanone A and a pair of C-3 epimer, are the first identified dimeric napthohydroquinone glycosides from the Rubia plants. All naphthohydroquinone dimers were evaluated for their cytotoxicities against ten tumor cell lines and effects on the tumor-associated NF-kappa B signaling pathway, and rubioncolin C showed the best cytotoxicity with IC50 value of 1.53 mu M and NF-kappa B inhibitory activity with IC50 value of 2.97 mu M. These results also demonstrated that the key roles of C-3 configuration and sugar group for biological activities of rubipodanone C. (C) 2017 Elsevier Ltd. All rights reserved.
[1]China Pharmaceut Univ, Sch Tradit Chinese Pharm, Nanjing 211198, Jiangsu, Peoples R China.
[2]China Pharmaceut Univ, State Key Lab Nat Med, Nanjing 211198, Jiangsu, Peoples R China.
[3]Chinese Acad Sci, Kunming Inst Bot, State Key Lab Phytochem & Plant Resources West Chi, Kunming 650201, Yunnan, Peoples R China.
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