Discovery, Characterization, and Anti-XOD Activity\nof Calcium Metallophore from <i>Coix lacryma-jobi</i>

In this work, coixalkyne\nA (<b>1</b>), a natural polynuclear\ncalcium complex with a novel cross-shaped molecular architecture,\nwas isolated from <i>Coix lacryma-jobi</i> L. along with\nthe undescribed analogue coixalkyne B (<b>2</b>). Their structures\nwere identified by means of NMR spectroscopy, ECD calculations, and\nsingle-crystal X-ray diffraction. It is noteworthy that the calcium\nligands of <b>1</b> as well as compound <b>2</b> possess\nrare terminal alkynes and a <i>nor</i>-carbon sesquiterpene\n(C14) framework. The antihyperuricemic activity of <i>C. lacryma-jobi</i> and xanthine oxidase (XOD) inhibitory effects of <b>1</b>–<b>2</b> were elucidated by <i>in vivo</i> and <i>in vitro</i> assays, while the possible mechanism of action\nwas suggested by molecular docking. Different from the reported chemical\nsynthesis and protein calcium carriers, the discovery of compounds <b>1</b> and <b>2</b> provided new proof for the natural calcium\nmetallophore in plants with xanthine oxidase inhibitory activity.