Improving phenolic bioactive-linked anti-hyperglycemic functions of dark germinated barley sprouts (Hordeum vulgare L.) using seed elicitation strategy

Sprouts of cereal grains, such as barley (Hordeum vulgare L.), are a good source of beneficial phenolic bioactives. Such health relevant phenolic bioactives of cereal sprouts can be targeted to manage chronic hyperglycemia and oxidative stress commonly associated with type 2 diabetes (T2D). Therefore improving phenolic bioactives by stimulating plant endogenous defense responses such as protective pentose phosphate pathway (PPP) during sprouting has significant merit. Based on this metabolic rationale, this study aimed to enhance phenolic bioactives and associated antioxidant and anti-hyperglycemic functions in dark germinated barley sprouts using exogenous elicitor treatments. Dark-germinated sprouts of two malting barley cultivars (Pinnacle and Celebration), treated with chitosan oligosaccharide (COS) and marine protein hydrolysate (GP), were evaluated. Total soluble phenolic content (TSP), phenolic acid profiles, total antioxidant activity (TA) and in vitro inhibitory activities of hyperglycemia relevant alpha-amylase and alpha-glucosidase enzymes of the dark germinated barley sprouts were evaluated at day 2, 4, and 6 post elicitor treatments. Overall, TSP content, TA, and alpha-amylase inhibitory activity of dark germinated barley sprouts decreased, while alpha-glucosidase inhibitory activity and gallic acid content increased from day 2 to day 6. Among barley cultivars, high phenolic antioxidant-linked anti-hyperglycemic bioactives were observed in Celebration. Furthermore, GP and COS seed elicitor treatments in selective doses improved T2D relevant phenolic-linked anti-hyperglycemic bioactives of barley spouts at day 6. Therefore, such seed elicitation approach can be strategically used to develop bioactive enriched functional food ingredients from cereal sprouts targeting chronic hyperglycemia and oxidative stress linked to T2D.