Optimization of linseed cultivation, a promising way to enhance its secoisolariciresinol diglucoside lignan content

Abstract

There is strong evidence on the anticancer properties of secolariciresinol diglucoside (SDG), the predominant flaxseed lignan, especially for mammary and prostatic carcinomas. Although the effect of cultivar and location on flaxseed SDG level has been reported, much less is traced regarding the influence of agronomical treatments. The purpose of this study is to determine if agricultural management practices could enhance SDG accumulation in flaxseed. We studied the effect of irrigation frequencies (I), added nutrients (N, zinc and humic acid) and fertilization treatments (F) and their interactions on SDG level and seed yield of the Egyptian flax cultivar Giza 9. Samples were extracted and analyzed for SDG, after alkaline hydrolysis, using HPLC-UV method. The concentration of SDG and its yield varied between 415.55-845.95 mg/100 g whole seeds and 1.77-4.05 Kg/feddan on a dry weight basis, respectively according to different agricultural treatments. I, N and F factors and their interactions had a significant effect on SDG. I × N × F interaction contributed to the majority of SDG variation (31.81 %), followed by I factor (27.96 %), whereas seed yield was more affected by F factor (72.7 %). The I × F interaction was the only significant interaction on the seed yield contributing only for 0.43% of the variance. Moderate irrigation frequency with the humic acid foliar application and mineral nitrogen fertilizer was the best combination for achieving the highest SDG levels. Using optimum agronomic practice would benefit the nutraceutical industry by optimizing flaxseed lignan content and hence enhancing its anticancer, health-promoting effect.