VARIABILITY IN ANTICANCER LIGNAN LEVELS IN FLAXSEED

Flaxseed and its major mammalian lignan precursor secoisolariciresinol diglycoside have been, shown to be protective against chemically indu ced carcinogenesis in animal models. Although flaxseed is the richest source of mammalian lignan precursors, it is not known whether these l evels vary with source. Thus the objective of this study was to determ ine how lignan levels in flaxseed are affected by variety, growing loc ation, harvest year, and seeding time. Ten varieties of flaxseed (AC L inora, Andro, Flanders, Linott, McGregor, Noralta, NorLin, NorMan, Som me, and Vimy) were subjected to 1) in vitro fermentation with human fe cal inoculum for 24 hours under anaerobic conditions to assess mammali an lignan production and 2) high-performance liquid chromatography (HP LC) analysis for secoisolariciresinol levels. Three of these varieties (Linott, McGregor, and NorLin) were grown in four locations, seeded e arly (May) for three different years, and, in one year seeded early (M ay) or late (June). Significant differences in lignan production were observed among the different varieties, ranging from 0.96 mu mol/g for Linott to 3.15 mu mol/g for Somme flaxseed (p < 0.05). Growing locati on had significant effects on lignan production from all three varieti es. Harvest year significantly affected only the Linott variety (p < 0 .05), whereas seeding time had no effect. A significant correlation (r = 0.572, p < 0.003) was observed between lignan values obtained from HPLC and in vitro fermentation methods, indicating that HPLC analysis of flaxseed may be used as a predictor of its lignan production levels . Differences due to variety harvest location, and harvest year of fla xseed should be taken into consideration when tumorigenesis studies ar e designed.