Pipercyclobutanamide D, a new member of the cyclobutanamide-type alkaloid, from the roots of .

From the EtOH-soluble extract of the roots of , one new dimeric alkamide, pipercyclobutanamide D () was isolated. Its structure was elucidated on the basis of NMR spectroscopic interpretation. The relative configuration of was determined based on the NOESY analysis. Compound showed -glucosidase inhibitory activity with an IC value of 158.5 µM. In addition, compound exhibited cytotoxicity against the MCF-7 and HepG2 cell lines with the IC values of 45.6 and 63.9 µM, respectively. Plausible biosynthetic pathway for the formation of was proposed based on regioselective [2 + 2] cycloaddition reaction.