Oxoisoaporphines from Menispermum dauricum Yukihiro Sugimoto a, *, Hind A.A. Babiker a , Shinobu Inanaga a , Masako Kato b , Akira Isogai c a Arid Land Research Center, Tottori University, 1390 Hamasaka, Tottori, 680-0001, Japan b Department of Chemistry, Nara Women's University, Kita-uoya-nishi machi, Nara, 630-8506, Japan c Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, 630-0101, Japan Received 19 November 1998; received in revised form 15 April 1999 Abstract Two oxoisoaporphine alkaloids, 2,3-dihydrodauriporphine and tyraminoporphine, together with the known alkaloid dauriporphine, were isolated from Menispermum dauricum roots cultured in a medium containing ketoconazole, a cytochrome P- 450 inhibitor. Structures of the alkaloids were established by spectroscopic, crystallographic and chemical methods. # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Menispermum dauricum; Menispermaceae; Root culture; Oxoisoaporphine alkaloids; Dauriporphine; 2,3-Dihydrodauriporphine; Tyra- minoporphine 1. Introduction Menispermum dauricum (Menispermaceae) has been reported to be the only source of naturally occurring oxoisoaporphine alkaloids (Sugimoto, 1999). Seven oxoisoaporphines have been identi®ed and isolated from intact M. dauricum plants: menisporphine (Kunitomo & Satoh, 1983), 2,3-dihydromenisporphine (Kunitomo, Kaede & Satoh, 1985), 6-O-demethylme- nisporphine (Hu et al., 1993), bianfugecine, bianfuge- dine (Hou & Xue, 1985), dauriporphine (bianfugenine) (Takani, Takasu & Takahashi, 1983) and dauriporphi- noline (Zhao, Ye, Tan, Zhao & Xia, 1989). In a previous paper (Sugimoto, Uchida, Inanaga & Isogai, 1997) we reported that cultured M. dauri- cum roots treated with ketoconazole, a cytochrome P-450 inhibitor, produced tyramine and two uniden- ti®ed alkaloids with molecular weights of 353 and 426. Precursor administration experiments showed that both alkaloids are derived from tyrosine. This paper reports on their isolation and structural eluci- dation. 2. Results and discussion Chromatographic separation of the basic fraction from cultured M. dauricum roots yielded two alkaloids, 1 and 2, as yellow needles and orange prisms, respect- ively. Phytochemistry 52 (1999) 1431±1435 0031-9422/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0031-9422(99)00330-1 * Corresponding author. Tel.: +81-857-21-7035; fax: +81-857-29- 6199. E-mail address: sugimoto@center.tottori-u.ac.jp (Y. Sugimoto).