title: Large-scale separation of antipsychotic alkaloids from Rauwolfia tetraphylla L. by pH-zone-refining fast centrifugal partition chromatography.
abstract: pH-zone-refining centrifugal partition chromatography was successively applied in the large-scale separation of close R(f)  antipsychotic indole alkaloids directly from CHCl(3)  fraction of Rauwolfia tetraphylla leaves. Two experiments with increasing mass from 500 mg to 3 g of crude alkaloid extracts (1C) of R. tetraphylla were carried out in normal-displacement mode using a two-phase solvent system composed of methyl tert-butyl ether/ACN/water (4:1:5, v/v/v) where HCl (12 mM) was added to the lower aqueous stationary phase as a retainer and triethylamine (5 mM) to the organic mobile phase as an eluter. The two centrifugal partition chromatography separations afforded a total of 162.6 mg of 10-methoxytetrahydroalstonine (1) and 296.5 mg of isoreserpiline (2) in 97% and 95.5% purity, respectively, along with a 400.9 mg mixture of α-yohimbine and reserpiline (3 and 4). Further, this mixture was resolved over medium pressure LC using TLC grade silica gel H (average particle size 10 μm), which afforded 160.4 mg of α-yohimbine (3) and 150.2 mg of reserpiline (4) in >95% purities. The purity of the isolated antipsychotic alkaloids was analyzed by high-performance LC and their structures were characterized on the basis of their 1D, 2D NMR and electrospray ionization-mass spectroscopic data.
authors: Medicinal Chemistry Department, Central Institute of Medicinal and Aromatic Plants, Council of Scientific and Industrial Research (CSIR), Lucknow, India.
authors: Anupam
authors: A
authors: Maurya
authors: Shikha
authors: S
authors: Gupta
authors: Santosh K
authors: SK
authors: Srivastava
mesh_terms: D000470:Alkaloids / Q000302:isolation & purification*; D014150:Antipsychotic Agents / Q000302:isolation & purification*; D003377:Countercurrent Distribution / Q000295:instrumentation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D010936:Plant Extracts / Q000302:isolation & purification*; D011926:Rauwolfia / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D014150:Antipsychotic Agents; D010936:Plant Extracts