Constituent Composition of Seeds from Crambe kotschyana

Abstract

Crambe kotschyana Boiss. [C. cordifolia subsp. kotschyana (Boiss.) Jafri] is a perennial herbaceous feed plant of the family Brassicaceae that is broadly distributed over Uzbekistan [1]. We studied previously the alkaloids and several lowmolecular-weight metabolites from the aerial part of this plant [2, 3]. The sulfur-containing alkaloids goitrin and goitridin [2] and the known compound N-(benzimidazolyl-2)-O-ethylcarbamate [4] were isolated from alkaloid fractions from the aerial part and roots of C. kotschyana. Previous GC-MS analysis of total alkaloids from the aerial part of C. kotschyana found the S-containing alkaloid goitrin, esters of oleic and palmitic acids, hydrocarbon 3-methyldodecane, and different derivatives of hydrocarbons (1,3-dimethoxybutane, tetradecyliodide, N-methylaminoheptane, etc.) [3]. The alkaloids from C. kotschyana seeds have not been reported. We studied the constituent composition of seeds collected during fruit ripening in Tashkent District, Uzbekistan, in order to compare the compositions of seeds and the aerial part of C. kotschyana. The usual CHCl 3 extraction of previously ground and defatted (benzene) seeds afforded after the appropriate work up the total alkaloids (0.19% of air-dried raw material mass). TLC on silica gel showed that the total alkaloids from C. kotschyana seeds did not include the principal S-containing alkaloid of the aerial part, i.e., goitrin (R f 0.5, mobile phase 1). Work up of the obtained mixture of bases with Et 2 O isolated a light-yellow oily compound with R f 0.85 (mobile phase 2) that was not an alkaloid. GC-MS showed that the retention time (3.255 min) of the isolated compound agreed with that of the known compound protoanemonin (5-methylidenefuran-2-one), which was observed in several plant species of the family Ranunculaceae [5]. Total alkaloids from C. kotschyana seeds were analyzed by GC-MS (Table 1). The compounds in it were observed for the first time in plants of the genus Crambe. The principal constituents of the seed fraction were benzoic and pyrrolidinecarboxylic acid esters and S-containing compounds dimethyl trisulfide and divinylsulfide. The aerial part gave esters of oleic and palmitic acids and the aforementioned hydrocarbons. GC-MS analysis was performed on an Agilent 7890A GC gas chromatograph with an Agilent 5975C quadrupole