From the alkaloids of the seeds of Stephania cepharantha HAYATA (Japanese name "tamasaki-tsuzurafuji") cultivated in Japan, a new dehydroaporphine type alkaloid, dehydrostephanine was isolated together with dehydrocrebanine (2), stephanine (3), crebanine (4), isotetrandrine (5), O-nornuciferine (6), stesakine (7) and berbamine (8). The structure of dehydrostephanine was established as 1 from various spectral data and identified to be a compound derived from stephanine (3) by iodine-oxidation. The 1.2.8.9-substituted [(7), (4), (2)] and the 1.2.8-substituted [(3), (1)] aporphine type alkaloids in this plant were assumed to be formed from dienone-phenol rearrangement of orientalinone (9) and dienol-benzene rearrangement of orientalinol (10), respectively.