Concentration Kinetics of Secoisolariciresinol Diglucoside and its Biosynthetic Precursor Coniferin in Developing Flaxseed Jingjing Fang, a Aina Ramsay, b Christian Paetz, a Evangelos C. Tatsis, a Sullivan Renouard, c Christophe Hano, c Eric Grand, d Ophélie Fliniaux, b Albrecht Roscher, e Francois Mesnard b and Bernd Schneider a * ABSTRACT: Introduction – In the plant kingdom, flaxseed (Linum usitatissimum L.) is the richest source of secoisolariciresinol diglucoside (SDG), which is of great interest because of its potential health benefits for human beings. The information about the kinetics of SDG formation during flaxseed development is rare and incomplete. Objective – In this study, a reversed-phase high-performance liquid chromatography–diode array detection (HPLC-DAD) method was developed to quantify SDG and coniferin, a key biosynthetic precursor of SDG in flaxseed. Methodology – Seeds from different developmental stages, which were scaled by days after flowering (DAF), were harvested. After alkaline hydrolysis, the validated HPLC method was applied to determine SDG and coniferin concentrations of flaxseed from different developing stages. Results – Coniferin was found in the entire capsule as soon as flowering started and became undetectable 20 DAF. SDG was detected 6 DAF, and the concentration increased until maturity. On the other hand, the SDG amount in a single flaxseed approached the maximum around 25 DAF, before desiccation started. Concentration increase between 25 DAF and 35 DAF can be attributed to corresponding seed weight decrease. Conclusion – The biosynthesis of coniferin is not synchronous with that of SDG. Hence, the concentrations of SDG and con- iferin change during flaxseed development. Copyright © 2012 John Wiley & Sons, Ltd. Keywords: HPLC-DAD; coniferin; flaxseed; secoisolariciresinol diglucoside; Linum usitatissimum Introduction Flax is an economically important fibre and oil plant. The seeds are used for food and feed purposes in many parts of the world. They contain high concentrations of digestible proteins, soluble fibre, soluble polysaccharides and oil; the oil is rich in omega-3 fatty acids (e.g. a-linolenic acid, 45–52% of total fatty acids). Additionally, flaxseed is the richest source of nutritional lignans in plants. Altogether, these components contribute to the nutri- tional and health functions of flaxseed diets (Oomah, 2001). Lignans are phenolic compounds that are formed from two phenylpropanoid moieties, which are C–C coupled through the 8 and 8΄ positions (Moss, 2000). The biological functions of these compounds for flaxseed are still unknown. The strong anti- oxidant activity of lignans (Hu et al., 2007) has led to the hypoth- esis that they protect abundant polyunsaturated fatty acids in the embryo from oxidation (Hano et al., 2006). Additionally, lignans may be involved in flaxseed defence against pathogens, predators and other biotic stresses (Dixon et al., 2002). In the past few decades, flaxseed lignans have become of great interest because of their wide spectrum of biological activity and potentially beneficial health functions, such as anti-oxidant, anti-cancer and diabetes prevention. Most of the biological effects of flaxseed lignans are attributed to the predominant compound, secoisolariciresinol diglucoside (SDG; 6, Fig. 1), and its mammalian lignan derivatives, enterolactone and enterodiol, which are formed from SDG by the action of intestinal bacteria in the human colon (Westcott and Muir, 2003; Eeckhaut et al., 2008; Adolphe et al., 2010). However, free SDG has rarely been detected in flaxseed at any developmental stage (Ford et al., 2001; Hano et al., 2006). Directly after its formation, SDG is assembled into lignan macromolecules (7, Fig. 1). From one to seven SDG units are connected by 3-hydroxy-3-methylglutaric * Correspondence to: B. Schneider, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, Beutenberg Campus, 07745 Jena, Germany. E-mail: schneider@ice.mpg.de a Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, Beutenberg Campus, 07745 Jena, Germany b Université de Picardie Jules Verne, EA3900 – BioPI ‘Biologie des Plantes et Contrôle des Insectes Ravageurs’ , Faculté de Pharmacie, 1 rue des Louvels, 80037 Amiens cedex, France c Laboratoire de Biologie des Ligneux et des Grandes Cultures, UPRES EA 1207, Antenne Scientifique Universitaire de Chartres, 21, rue de Loigny-la- Bataille, 28000 Chartres, France d Laboratoire des Glucides CNRS UMR 6219, Faculté des Sciences, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens, France e Génie Enzymatique et Cellulaire, UMR CNRS 6022, Université de Picardie, 33, rue Saint-Leu, 80039 Amiens, France Phytochem. Anal. 2013, 24, 41–46 Copyright © 2012 John Wiley & Sons, Ltd. Research Article Received: 2 February 2012, Revised: 27 April 2012, Accepted: 30 April 2012 Published online in Wiley Online Library: 12 June 2012 (wileyonlinelibrary.com) DOI 10.1002/pca.2377 41