pubs.acs.org/JAFC Published on Web 06/18/2009 © 2009 American Chemical Society J. Agric. Food Chem. 2009, 57, 6101–6106 6101 DOI:10.1021/jf901215j Biotransformation of Sesaminol Triglucoside to Mammalian Lignans by Intestinal Microbiota KUO-CHING JAN, † LUCY SUN HWANG,* ,† AND CHI-TANG HO* ,†,‡ † Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan, and ‡ Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey 08901-8520 Plant lignans occur widely in foods, with flaxseed recognized as their richest source. Some plant lignans can be converted by intestinal microbiota to the mammalian lignans, enterodiol and enterolactone, which may have protective effects against hormone-related diseases such as breast cancer. This study determined whether plant lignans in sesame seed, particularly sesaminol triglucoside (STG), could be metabolized to mammalian lignans. STG is a furofuran lignan with methylenedioxyphenyls. The transformation of furofuran lignans to mammalian lignans by intestinal microbiota involves the hydrolysis of glucoside, demethylenation of a methylene group, oxidation of dibenzylbutanediol to dibenzylbutyrolactone, and reductive cleavage of furofuran rings. STG has methylenedioxyphenyl moieties in their structures that may require additional oxidative demethyle- nation of the methylenedioxyphenyl ring for conversion to mammalian lignans. However, STG is metabolized, via intestinal microbiota, to a catechol moiety. The major STG metabolite was characterized as 4-[((3R,4R)-5-(6-hydroxybenzo[d][1,3]dioxol-5-yl)-4-(hydroxymethyl)tetrahydrofur- an-3-yl)methyl]benzene-1,2-diol using NMR and mass spectrometry, and STG could be converted to enterolactone and enterodiol by rat intestinal microflora. KEYWORDS: Sesaminol triglucoside; mammalian lignans; biotransformation; intestinal microbiota INTRODUCTION Sesame exhibits many beneficial physiological effects, which are mostly related to its lignan compounds, such as sesaminol glucosides. Sesaminol glucosides have no antioxidative properties in vitro, but they have been reported to be converted to phenolic compounds after oral administration and showed antioxidative activity ( 1- 3). Plant lignans, such as secoisolariciresinol, matair- esinol, lariciresinol, and pinoresinol, are converted to entero- lactone (ENL) and enterodiol (END) ( 4, 5) by the intestinal microbiota of humans and animals ( 6- 9). Nakai et al. ( 10) and Liu et al. ( 11) reported that sesamin undergoes cleavage of methylenedioxyphenyl (MDP) groups to catechol or methoxyca- techol in humans and in rats, respectively. Our previous studies reported that sesaminol triglucoside might be deglycosylated to form sesaminol, by intestinal microbiota, and then incorporated via lymphatic absorption into the cardiovascular system. LC-MS/ MS analysis of rat organs suggested that sesaminol triglucoside could be converted to mammalian lignans by rat intestinal microbiota ( 12). In this study, we investigated whether sesaminol triglucoside, a lignan isolated from sesame seed, is converted to the mammalian lignans in rats. In addition, we used incubation of sesaminol triglucoside with intestinal bacteria to identify major sesaminol triglucoside metabolites. MATERIALS AND METHODS Materials and Chemicals. Acetic acid was obtained from Sigma- Aldrich (Poole, Dorset, U.K.). XAD-2 gel was purchased from Aldrich (Milwaukee, WI). General anaerobic medium (GAM) broth was provided by Nissui (Tokyo, Japan). All other chemicals used were of analytical grade. Liquid chromatographic grade solvents and reagents were obtained from Mallinckrodt Baker (Phillipsburg, NJ). Triply deionized water (Millipore, Bedford, MA) was used for all preparations. Extraction and Isolation of Sesaminol Triglucoside (STG). Black sesame (Sesamum indicum) was supplied by Yuan-Shun Food Co. (Yun-Ling County, Taiwan). For the isolation of STG, sesame seeds were defatted with n-hexane and extracted with 80% MeOH. The 80% MeOH extract was charged into an Amberlite XAD-2 column and eluted with H 2 O, 20% MeOH, 40% MeOH, and 60% MeOH. The 60% MeOH fraction was then purified by preparative HPLC under the following conditions: column, Cosmosil ODS (250  20 mm i.d.); solvent, MeOH; flow rate, 4 mL/ min ( 13). The purity of STG was 99%. Animals and Diets. Our experimental protocol was approved by the National Laboratory Animal Center (Taipei, Taiwan). Inbred male Sprague-Dawley rats (body wt=275 ( 25 g, mean ( SD) were housed in pairs in cages in a room with controlled temperature (20-22 °C), relative humidity (50-70%), and a 12 h light/dark cycle (lights on at 7:00 a.m.). The rat diet was an AIN 93 M diet (Purina Mills, St. Louis, MO). Rats consumed their food ad libitum and had unlimited access to water; their weight and food consumption were determined weekly. *Authors to whom correspondence should be addressed [(C.-T.H) telephone (732) 932-9611, ext. 235, fax (732) 932-6776, e-mail ho@AESOP.Rutgers.edu; (L.S.H.) telephone 886-23629984, fax 886-2-3366-4113, e-mail lshwang@ntu.edu.tw].