[Anthraquinones from the roots of Knoxia valerianoides].
OBJECTIVE
To investigate the chemical constituents of the roots of Knoxia valerianoides and their biological activities.


METHODS
The anthraquinones were isolated by using a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, and reversed-phase HPLC. Structures of the isolates were identified by their physical-chemical properties and spectroscopic analysis including 2D NMR and MS. Antioxidant, anti-HIV, neuroprotective, and cytotoxic activities were screened by using cell-based models.


RESULTS
Twenty-two constituents were isolated from an ethanolic extract of the roots of K. valerianoides. Their structures were identified as nordamnacanthal (1), ibericin (2), rubiadin (3), damnacanthol (4), 2-ethoxymethylknoxiavaledin (5), 3-hydroxymorindone (6), knoxiadin (7), 2-formyl knoxiavaledin (8), lucidin (9), xanthopurpurin (10), 1, 3-dihydroxy-2-methoxy-9, 10- anthraquinone (11), lucidin(-methyl ether (12), digiferruginol (13), 3-hydroxy-2-methyl-9,10-anthraquinone (14), rubiadin-1-methyl ether (15), 6-methoxylucidin (-ethyl ether (16), 1,3,6-trihydroxy-2-methyl-9,10-anthraquinone (17), 1,3-dihydroxy-2-hydroxy methyl-6-methoxy-9,10-anthraquinone (18), 1,3,6-trihydroxy-2-methoxymethyl-9,10- anthraquinone (19), 3,6-dihydroxy-2- hydroxymethyl-9,10-anthraquinone (20), and 1,6-dihydroxy-2-methyl-9,10-anthra quinone (21). In the in vitro assays, at a concentration of 1 x 10(-5) mol x L(-1), no compounds were active against human cancer cell lines (HCT-8, Bel7402, BGC-823, A549, and A2780), deserum and glutamate induced PC12-syn cell damage, LPS induced NO production in macrophage, Fe2+-cystine induced rat liver microsomal lipid peroxidation, HIV-1 replication, and protein tyrosine phosphatase 1B (PTP1B).


CONCLUSIONS
Compounds 9-21 were obtained from the roots of K. valerianoides for the first time.
State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Ministry of Education, Institute of Materia Medica, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China.
Feng
F
Zhao
Sujuan
S
Wang
Xiuli
X
Wu
Yang
Y
Yu
Zhenggang
Z
Yue
Bo
B
Liu
Sheng
S
Lin
Chenggen
C
Zhu
Yongchun
Y
Yang
Jiangong
J
Shi
D000818:Animals; D000880:Anthraquinones / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002460:Cell Line; D004365:Drugs, Chinese Herbal / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry; D051381:Rats; D019666:Rubiaceae / Q000737:chemistry*
D000880:Anthraquinones; D004365:Drugs, Chinese Herbal