Qualitative and quantitative analysis of the major phenolic compounds as antioxidants in barley and flaxseed hulls using HPLC/MS/MS

Both qualitative and quantitative analyses of the major phenolic compounds in barley and flaxseed hulls were conducted using reverse phase high-performance liquid chromatography coupled with photodiode array detection and quadrupole time-of-flight mass spectrometry. Ferulic acid, p-coumaric acid, vanillic acid and vanillin were identified and quantified in four barley hull samples. Four ferulate dehydrodimers were also detected. The phenolic compounds of flaxseed hull were distinct from those of barley hull. Three flaxseed hull samples varied significantly (P< 0.05) in their contents of secoisolariciresinol diglucoside (16.38 to 33.92 g per kg), coumaric acid glucoside (35.68 to 49.22 g per kg) and ferulic acid glucoside (5.07�15.23 g per kg). The phytochemical profiles of co-extracts featured the major phenolic compounds from both barley and flaxseed hulls. The total phenolic content and 2,2-diphenyl-1-picrylhydrazyl radical-scavenging capacity varied significantly (P< 0.05) among different varieties of flaxseed and barley hulls. As agricultural by-products, barley and flaxseed hulls may be utilised as potential sources of functional food ingredients through extraction and concentration of the phytochemicals identified above. (Authors abstract)
The main objectives of the present study were to investigate the phytochemical profile of extracts of barley and flaxseed hulls and to evaluate their antioxidant capacity using chemical assays. Both qualitative and quantitative analyses were conducted on the major phenolic compounds in barley and flaxseed hulls hydrolysed by calcium hydroxide. Based on the diverse and enriched phytochemical profiles, co-extraction of barley hull with flaxseed hull indicates a potential approach to convert barley hull into value-added functional food ingredients. Further research is being conducted to assess the cellular antioxidant and anti-proliferative activities of hull extracts on prostate cancer cells.  (Editors comments)