A new alkaloid, named 6-(2′,3′-dihydroxy-4′-hydroxymethyl-tetrahydro-furan-1′-yl)cyclopentadiene[c]pyrrole-1,3-diol, was isolated from the seeds of Castanea mollissima Blume. The structure was elucidated based on spectroscopic evidence including 2D NMR techniques. © 2008 Li Jun Wu.