Phytochemical investigation of the seeds of Coix lacryma-jobi var. lacryma-jobi resulted in the isolation of eight compounds, including two new structures, coixdines A-B (1-2) and six known compounds (3-8). The structures of these compounds were determined by 1 D and 2 D NMR spectra referring to the literatures, together with HR-MS analysis. Coixdine A and B are first examples of spermidine skeleton in genus Coix. In the present paper, all compounds were evaluated for the cytotoxicity against two cancer cell lines (CT-26 and BxPC-3) in vitro, and none of the compounds exhibited obvious cytotoxic activity. The present investigation suggests that these amides seem to be of great chemotaxonomic value for C. lacryma-jobi.
Keywords: Coix; Coix lacryma-jobi; amide; natural product; spermidine skeleton.