Thompson L U, Rickard S E, Cheung F, Kenaschuk E O, Obermeyer W R
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.
Nutr Cancer. 1997;27(1):26-30. doi: 10.1080/01635589709514497.
Flaxseed and its major mammalian lignan precursor secoisolariciresinol diglycoside have been shown to be protective against chemically induced carcinogenesis in animal models. Although flaxseed is the richest source of mammalian lignan precursors, it is not known whether these levels vary with source. Thus the objective of this study was to determine how lignan levels in flaxseed are affected by variety, growing location, harvest year, and seeding time. Ten varieties of flaxseed (AC Linora, Andro, Flanders, Linott, McGregor, Noralta, NorLin, NorMan, Somme, and Vimy) were subjected to 1) in vitro fermentation with human fecal inoculum for 24 hours under anaerobic conditions to assess mammalian lignan production and 2) high-performance liquid chromatography (HPLC) analysis for secoisolariciresinol levels. Three of these varieties (Linott, McGregor, and NorLin) were grown in four locations, seeded early (May) for three different years, and, in one year, seeded early (May) or late (June). Significant differences in lignan production were observed among the different varieties, ranging from 0.96 mumol/g for Linott to 3.15 mumol/g for Somme flaxseed (p < 0.05). Growing location had significant effects on lignan production from all three varieties. 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 flaxseed should be taken into consideration when tumorigenesis studies are designed.
亚麻籽及其主要的哺乳动物木脂素前体开环异落叶松脂醇二糖苷已被证明在动物模型中对化学诱导的致癌作用具有保护作用。尽管亚麻籽是哺乳动物木脂素前体最丰富的来源，但尚不清楚这些含量是否因来源而异。因此，本研究的目的是确定亚麻籽中的木脂素含量如何受到品种、种植地点、收获年份和播种时间的影响。对十个亚麻籽品种（AC Linora、Andro、Flanders、Linott、McGregor、Noralta、NorLin、NorMan、Somme和Vimy）进行了以下实验：1）在厌氧条件下用人粪便接种物进行24小时体外发酵，以评估哺乳动物木脂素的产生；2）采用高效液相色谱（HPLC）分析法测定开环异落叶松脂醇的含量。其中三个品种（Linott、McGregor和NorLin）在四个地点种植，连续三年于五月早播，并且在其中一年分别于五月早播或六月晚播。不同品种之间的木脂素产生量存在显著差异，Linott品种为0.96 μmol/g，Somme亚麻籽为3.15 μmol/g（p < 0.05）。种植地点对所有三个品种的木脂素产生均有显著影响。收获年份仅对Linott品种有显著影响（p < 0.05），而播种时间没有影响。通过HPLC法和体外发酵法获得的木脂素值之间存在显著相关性（r = 0.572，p < 0.003），这表明对亚麻籽进行HPLC分析可作为其木脂素产生水平的预测指标。在设计肿瘤发生研究时，应考虑亚麻籽品种、收获地点和收获年份的差异。
