title: (±)-Quassidines I and J, two pairs of cytotoxic bis-β-carboline alkaloid enantiomers from Picrasma quassioides.
abstract: (±)-Quassidines I (1) and J (2), two pairs of new bis-β-carboline alkaloid enantiomers, were isolated from the stems of Picrasma quassioides. Their structures were determined by the analysis of spectroscopic data, including HRESIMS and 2D NMR, and confirmed by single-crystal X-ray diffraction analysis. The racemic mixtures of 1 and 2 were resolved into two pairs of enantiomers, (+)-S-1a and (-)-R-1b and (+)-S-2a and (-)-R-2b, by HPLC using a chiral Daicel IB-3 column, respectively, which represents the first successful example to resolve bis-β-carboline racemic mixtures. The absolute configurations of the two pairs of enantiomers were determined by comparison between the calculated and experimental ECD spectra. The cytotoxicity evaluation revealed that (+)-S-1a and (+)-S-2a showed more potent cytotoxicity against human cervical HeLa and gastric MKN-28 cancer cell lines with IC50 values of 4.03-6.30 μM than their enantiomers with IC50 values of 9.64-12.3 μM; however, the two (+)-S-quassidines showed similar activities to their enantiomers against the mouse melanoma B-16 cancer cell line.
authors.affiliation: Key Laboratory for Marine Drugs, Department of Pharmacy, State Key Laboratory of Oncogenes and Related Genes, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University , Shanghai 200127, People's Republic of China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Jiao
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Gao
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Gu
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Xu
authors.forename: Hao-Bing
authors.initials: HB
authors.lastname: Yu
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Shi
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Yao
authors.forename: Hou-Wen
authors.initials: HW
authors.lastname: Lin
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification*; D000818:Animals; D002243:Carbolines / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D006801:Humans; D051379:Mice; D015394:Molecular Structure; D032270:Picrasma / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D002243:Carbolines; C000595944:quassidine I