Examination of alkaloidal constituents of zanthoxylum usambarense by a combination of ion-pair extraction and ion-pair chromatography using sodium perchlorate
Juma, Francis D.
Nganga, Joseph N
Mathenge, Simon G.
Ogeto, John O.
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Quaternary alkaloids of the stem of Zanthoxylum usambarense, an important medicinal plant in Kenya utilized for the treatment of pneumonia and rheumatism, were examined by a combination of ion-pair extraction and preparative ion-pair high performance liquid chromatography (HPLC), in which sodium perchlorate was used as an ion-pair reagent. Quaternary bases were extractable from aqueous solution into I ,2-dichloroethane in the presence of perchlorate in acidic conditions. The phenomenon is explained in terms of ion-pair extraction between alkaloidal cation and perchlorate anion. The quaternary alkaloidal fraction thus obtained was well separated by means of ion-pair HPLC in which sodium perchlorate was also utilized. Furthermore, the solvent system was easily applied to preparative HPL " yielding the pure perchlorate of each alkaloid. Eight quaternary bases in Z. usambarense were thus obtained and their structures were elucidated. One of them wa a new quaternary base of the tetrahydroproloberberine type, which was named (-)-usambarine.
CitationPhytochemical analysis Vol. 6
Department of Natural Medicinal Chemistry, Kobe Pharmaceutical UniversityDepartment of Medicine, University of NairobiDepartment of Botany, University of NairobiDepartment of Pharmacy, University of Nairobi
ion-pair high performance liquid chromatography;
Zanthoxylum usambarense .