title: Bioassay guided discovery of apoptosis inducers from gamboge by high-speed counter-current chromatography and high-pressure liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry.
abstract: A screening system, composed of high-speed counter-current chromatography and high-pressure liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry, was established to find bioactive lead compound. This system succeeded in discovering apoptosis inducers from gamboge, the resin of Garcinia hanburyi. High-speed counter-current chromatography was used to provide well-separated fractions for bioassay and the resulted active fractions were rapidly identified using high-pressure liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry. The solvent system of n-hexane/ethyl acetate/methanol/water was optimized to the ratio of 7:3:7:3 (v/v/v/v) by a K value analysis. As a result, two active fractions were obtained. They showed apoptosis inducing effects as potent as that of taxol (500 nM) at the concentration of 1 microg/ml. Gambogenic acid (72.1%) and epimeric isogambogic acids (25.3%) were identified in one of the fractions. The other active fraction mainly contained two epimeric mixtures, gambogic acids (68.7%) and gambogoic acids (26.9%). Among them, gambogenic acid, without epimerization, has priority to be lead compound.
authors.affiliation: Chinese Medicine Laboratory, Hong Kong Jockey Club Institute of Chinese Medicine, Shatin, Hong Kong, PR China.
authors.forename: Quan-Bin
authors.initials: QB
authors.lastname: Han
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Chao
authors.initials: C
authors.lastname: Feng
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.forename: Sheng-Xiong
authors.initials: SX
authors.lastname: Huang
authors.forename: Song-Lin
authors.initials: SL
authors.lastname: Li
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Qiao
authors.forename: Jing-Zheng
authors.initials: JZ
authors.lastname: Song
authors.forename: Donald C
authors.initials: DC
authors.lastname: Chang
authors.forename: Kathy Q
authors.initials: KQ
authors.lastname: Luo
authors.forename: Hong-Xi
authors.initials: HX
authors.lastname: Xu
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001681:Biological Assay; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003377:Countercurrent Distribution / Q000379:methods*; D029760:Garcinia / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D044004:Xanthones / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D044004:Xanthones; C052659:gambogic acid