Anun Ounaroon. Formation of deacetylisoipecoside from dopamine and secologanin by using enzyme in Alangium salviifolium. Master's Degree(Pharmacognosy). Chulalongkorn University. Office of Academic Resources. : Chulalongkorn University, 1995.
Formation of deacetylisoipecoside from dopamine and secologanin by using enzyme in Alangium salviifolium
Abstract:
Two new enzymes involved in the stereospecific condensation of dopamine and secologanin were discovered in the crude enzyme extracts prepared from the leaves of A. salviifolium. Both enzymes potentially catalyze the first reaction steps of the biosynthesis of monoterpenoid isoquinoline alkaloids (eg. Emetine, cephaeline) accumulated in this plant. The crude enzyme extracts appeared to condense dopamine and secologanin under the conditions of 100mM Tricine- NaOH buffer, pH 7.5, to form both deacetylipecoside (R-configuration) and deacetylisoipecoside (S-configuration) which were spontaneously converted to demethylalangiside and demethylisoalangiside, respectively. Identification of the reaction products was performed by using TLC, HPLC and LC-MS. The results obtained from the TLC Rf values, HPLC retention times, UV-absorption spectra and MS-spectra clearly showed that the immediate enzymatic products produced by the enzyme extracts of A. salviifolium were deaectylipecoside and deacetylisoipecoside. The discovery of these two new enzymes in A. salviifolium suggested that the C1-configuration (either R or S form) of various naturally ipecac alkaloids were determined by the first enzymatic step of dopamine and secologanin condensation