Isoquinoline alkaloids and keto-fatty acids of Argemone ochroleuca and A. mexicana (mexican poppy) seed. I. An assay method and factors affecting their concentration

Abstract

An assay for the isoquinoline alkaloids of Argemone ochroleuca and A. mexicana seeds is described. The method consists of extraction into weakly acidified methanol and ion-pair high performance liquid chromatography with sodium lauryl sulfate and tartaric acid in acetonitri1e:water as eluent. Analysis of A. ochroleuca seed showed it to contain dihydrosanguinarine and dihydrochelerythrine (c. 3 : 2) as major alkaloid components with minor amounts of protopine, sanguinarine, berberine and chelerythrine. A single sample of authenticated A. mexicana seed contained dihydrosanguinarine as the major alkaloid with minor amounts of sanguinarine and berberine, in agreement with earlier studies. Dihydrosanguinarine and dihydrochelerythrine were measured as their oxidized products, sanguinarine and chelerythrine, after U.V. irradiation. A crystalline solid which separates from A. ochroleuca seed oil was shown to contain 11-oxo-octacosanoic acid and 11-oxo-triacontanoic acid, which are also the major components of a similar solid from A. mexicana seed oil. Mexican poppy seed (probably A. ochroleuca) collected from various regions of Queensland during 1987-89 showed that place of origin and length of storage of intact seed had little effect on alkaloid levels. Exposure of crushed seed to light, however, caused a rapid decrease in the concentration of dihydro-alkaloids. Total alkaloid content correlated with seed maturity, with immature seed containing much less than mature seed.