New alkaloids from Capparis spinosa: Structure and X-ray crystallographic analysis

Fruits of Capparis spinosa contain a significant amount of compounds with many health benefits. Three new alkaloids, capparisine A (1), capparisine B (2), capparisine C (3), and two known alkaloids, 2-(5-hydroxymethyl-2-formylpyrrol-1-yl) propionic acid lactone (4), and N-(3′-maleimidy1)-5-hydroxymethyl-2-pyrrole formaldehyde (5) were isolated from the fruits of C. spinosa L. The five compounds were purified by solvent separation, column chromatography, and preparative HPLC, consecutively. The chemical structures of compounds 1–5 were established on the basis of a spectroscopic analysis, and the stereochemistries of compounds 1 and 2 were proved by X-ray crystallographic analysis. Nevertheless, the five compounds had no inhibitory effect on the human hepatocyte cell line HL-7702 apoptosis induced by Act D (200 ng/ml) and TNF-α (20 ng/ml) with high content screening assay.