Preparative Separation and Purification of Sesamin and Sesamolin from Sesame Seeds by High-Speed Counter-Current Chromatography

Sesame (sesamum indicum L.) seed, a major oil seed crop of high nutritional value, is widely cultivated throughout the world. It is not only a good source of edible oil but also widely used in baked goods and confectionery products (Namiki 1995). It is also considered to be a food beneficial to health in oriental countries (Fukuda and Namiki 1998). Sesame oil contains a class of unusual compounds known as lignans, comprising sesamin, sesamolin, and a small amount of sesamol (Namiki 1995). They have multiple physiological functions such as decreasing blood lipids (Kamal-Eldin et al 1995) and arachidonic acid levels (Shimizu et al 1991), increasing antioxidative ability (Hemalatha et al 2004) and gamma-tocopherol bioavailability (Lemeke-Norojarvi et al 2001), and providing antiinflammatory function (Hsu et al 2005) and estrogenic activity (Columan et al 2005; Wu et al 2006). In view of the wide range of biological activities, an efficient method for the preparative isolation and purification of sesamolin and sesamolin (Fig. 1) from natural sources is warranted. The conventional methods such as column chromatography and crystallization are tedious and often require several steps. High-speed counter-current chromatography (HSCCC) is a preparative all-liquid chromatographic technique based on partitioning of compounds between two immiscible liquid phases. Details about the operation principle can be found in various monographs (Ito 1986; Berthod 2002). In recent years, HSCCC has emerged as a superior technique for preparative separations of natural compounds (Berthod 2002). The application of HSCCC for the isolation of sesame lignans was studied.