Occurrence of bergenin phenylpropanoates in Vatica bantamensis Tetsuro Ito a, *, Yasumasa Hara a , Masayoshi Oyama a , Toshiyuki Tanaka b , Jin Murata c , Dedy Darnaedi d , Munekazu Iinuma a a Laboratory of Pharmacognosy, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan b Laboratory of Medicinal Resources, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan c Botanical Gardens, Koishikawa, Graduate School of Science, The University of Tokyo, 3-7-1, Hakusan, Bunkyo-Ku, Tokyo 112-0001, Japan d Research and Development Center for Biology, Indonesian Institute of Sciences (LIPI), Jalan Ir. H. Juanda 13, Bogor 16122, Indonesia 1. Introduction Dipterocarpaceaeous plants are abundant sources of various categorized polyphenols, i.e., oligostilbenoids, isocoumarin, lignan, acetophenones, and flavonoids (Abe et al., 2010; Ali et al., 2004; Ito, 2011; Ito et al., 2003a,b, 2004, 2010, 2012; Matsuda et al., 2009; Seo et al., 1999; Sotheeswaran and Pasupathy, 1993). Bergenin (9), the representative isocoumarin derivative in woody parts of the Dipterocarpaceae family, have been isolated from plants belonging to the tribe Dipterocarpeae (subfamily Dipterocarpoideae), which have been identified mainly by our previous phytochemical studies of some species of Vatica (Abe et al., 2010; Ito et al., 2003a; Seo et al., 1999), Vateria (Ito et al., 2003b), and Dipterocarpus (Ito et al., 2004). Although our accumulated chemical library was derived mainly from stem and bark samples, phenolic constituents have also been obtained from the leaves of some species, e.g., Upuna borneensis (Ito et al., 2012) and Vateria indica (Ito et al., 2010); however, comprehensive research on these constituents along with the structural diversity of bergenin derivatives needs further investiga- tion. In the present study, we focused on phenolic constituents present in Vatica bantamensis leaves, from which we isolated four new bergenin derivatives, i.e., bergenin 11-O-(E)-sinapate (1), bergenin 11-O-(E)-ferulate (2), bergenin 11-O-(Z)-ferulate (3), and bergenin 11-O-(Z)-coumalate (5), and five known derivatives, i.e., bergenin 11-O-(E)-coumalate (4) (Mebe and Makuhunga, 1992), bergenin 11-O-syringate (6) (Fujii et al., 1996), bergenin 11-O- vanillate (7) (Fujii et al., 1996), bergenin 11-O-p-hydroxybenzoate (8) (Jia et al., 1995), and 9. 2. Results and discussion The acetone extract of V. bantamensis was subjected to repeated open column chromatography and HPLC to purify the polar fractions that showed positive in Gibbs tests. Compounds (1–8) were obtained as colorless solids and all had a common isocoumarin core, i.e., bergenin (9). The structure elucidation for the new compounds (1, 2, 3, and 5) was similar. Thus, only the protocol followed for compound 1 is described in detail below. Comparative results based on substitutional differences on an aromatic ring and the geometrical isomerisms for 2–5 are discussed. NMR data analyses were conducted using the data measured in acetone-d 6 for 1, 2, 3, and 5 (Table 1). Known compounds (4, 6–9) were characterized by total analysis of their spectral data (MS, NMR) and comparison with previously reported spectral data (Fujii et al., 1996; Jia et al., 1995; Mebe and Makuhunga, 1992). Compound 1 was shown to possess an [MÀH] À ion at m/z 533.1301 in ESI-MS, which was attributable to the molecular formula C 25 H 26 O 13 . In the 1 H and 13 C NMR spectra (acetone-d 6 , Tables 1 and 2), we observed characteristic signals of a (E)-sinapyl Phytochemistry Letters 5 (2012) 743–746 A R T I C L E I N F O Article history: Received 19 March 2012 Received in revised form 31 July 2012 Accepted 1 August 2012 Available online 17 August 2012 Keywords: Vatica bantamensis Dipterocarpaceae Isocoumarin Bergenin phenylpropanoate Structure elucidation A B S T R A C T We isolated five bergenin phenylpropanoates, i.e., 11-O-(E)-sinapate (1), 11-O-(E)-ferulate (2), 11-O-(Z)- ferulate (3), 11-O-(E)-coumalate (4), and 11-O-(Z)-coumalate (5), and three bergenin hydroxybenzoates, i.e., 11-O-syringate (6), 11-O-vanillate (7), and 11-O-p-hydroxybenzoate (8), along with bergenin (9), from the leaves of Vatica bantamensis. Moreover, we identified the geometrical isomerization between 2 and 3. These structures were characterized by nuclear magnetic resonance (NMR). This is the first report that shows the occurrence of bergenin phenolic acid esters in dipterocarpaceaeous plants. ß 2012 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +81 58 230 8100; fax: +81 58 230 8105. E-mail address: teito@gifu-pu.ac.jp (T. Ito). Contents lists available at SciVerse ScienceDirect Phytochemistry Letters jo u rn al h om ep ag e: ww w.els evier.c o m/lo c ate/p hyt ol 1874-3900/$ – see front matter ß 2012 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.phytol.2012.08.004