Biflavonoids, Lignans, and Related Compounds from the Roots of Diplomorpha canescens by Hari Prasad Devkota* a ) b ), Khem Raj Joshi a ) b ), Takashi Watanabe c ), and Shoji Yahara* b ) a ) Program for Leading Graduate Schools, Health Life Sciences: Interdisciplinary and Glocal Oriented (HIGO) Program, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan b ) Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan (phone/fax: þ 81-96-3714381; e-mail: devkotah@kumamoto-u.ac.jp ( H. P. Devkota), yaharas1@gpo.kumamoto-u.ac.jp ( S. Yahara)) c )Research Organization for Regional Alliances, Kochi University of Technology, 185 Miyanokuchi, Tosayamada, Kami City, Kochi 782-0003, Japan Two new biflavonoids, 14’’-O-methyldihydrodaphnodorin B (1) and 14’’-O-methyldaphnodorin J (2), along with 16 known compounds, i.e. , dihydrodaphnodorin B ( 3), daphnodorin J (4), 3’’-epidihydro- daphnodorin B (5), daphnodorin B (6), neochamaejasmin B (7), sikokianin B (8), ()-syringaresinol (9),()-syringaresinol 4-O-b-d-glucopyranoside (10),(þ)-nortrachelogenin (11),()-lariciresinol (12), ()-pinoresinol (13), syringin (14), syringinoside (15), daphnoretin (16), phorbol 13-acetate (17), and methyl paraben (18) were isolated from the roots of Diplomorpha canescens ( Meisn.) C.A. Meyer. The structures were determined on the basis of spectroscopic data. Introduction. – Diplomorpha canescens (Meisn.) C.A. Meyer (Synonym: Wik- stroemia canescens Meisn. ), belonging to Thymelaeaceae family, is widely distributed throughout Nepal, Afghanistan, northern India, Sri Lanka, and China [1] . In Nepal, it is locally known as (Phurkepaat), and the stems are used against toothache in Nepal [2]. Roots are called as (Sanhijyou) in traditional Chinese medicine and used for the treatment of several disorders [3] and in antitumor therapy [4]. Previous phytochem- ical studies have revealed two tigliane-type diterpene esters, wikstroemia factors C 1 and C 2 , from the root of this plant [4]. We have previously reported six new and 26 known compounds from the aerial parts of D. canescens [5]. In this article, we report the isolation and structure elucidation of two new biflavonoids, 14’’-O-methyldihydro- daphnodorin B (1) and 14’’-O-methyldaphnodorin J (2 ; Fig. 1), along with 16 known compounds from the roots of D. canescens . Results and Discussion. – The dried roots of D. canescens (500 g) were extracted twice with 70% MeOH (4.5 l) , and extracts were evaporated under reduced pressure to give 70% MeOH extract (104 g). The extract was then separated into the H 2 O soluble (45 g) and H 2 O-insoluble parts (59 g). The H 2 O-insoluble part was subjected to repeated column chromatography on MCI gel CHP20P , Sephadex LH-20, octadecyl silica (ODS ), and silica gel to afford two new biflavonoids, 1 and 2, along with 16 known compounds. From the detailed spectral analysis and comparison with literature data, the known compounds were identified as six biflavonoids, i.e. , dihydrodaphnodorin B Helvetica Chimica Acta – Vol. 98 (2015) 704 # 2015 Verlag Helvetica Chimica Acta AG, Zürich