Stimulation of Phenolics, Antioxidant and α-Glucosidase Inhibitory Activities During Barley (Hordeum vulgare L.) Seed Germination.

Abstract

The rationale of this study was to enhance the nutritional quality of dry barley seeds. In this study we are evaluating the effect of germination on barley seeds relevant to total phenolic contents, antioxidant activity (in terms of DPPH free-radical scavenging) and the in vitro α-glucosidase inhibitory activities. Barley seeds were germinated for 18.5, 24, 30, 48, and 67h and then extracted in water. The total phenolic contents, antioxidant activities and α-glucosidase inhibitory activities changed with germination time. More specifically, within the first 48h of germination the total phenolic content increased from 1.1mg/gfresh weight (0h) to 3.4mg/gfresh weight (48h) and then slightly reduced by 67h. Similarly, α-glucosidase inhibitory activity was significantly increased from an IC50 128.82mg/mL (0h) to an IC50 18.88mg/mL (48h) and then slightly reduced by 67h. Significant maltase inhibitory activity was observed only with 48h-germinated extract. Antioxidant activities increased continuously from an IC50 15.72mg/mL at 0h to and IC50 5.72mg/mL after 48h of germination. Based on our observations, barley seed germination was over after 48h. During the progress of germination phenolic compounds are becoming available and are more easily extracted. After 48h, lignification is initiated resulting to the decreased total phenolic content and observed antioxidant and carbohydrate hydrolyzing enzyme inhibition activities. The above results indicate the positive effect of germination in barley seeds for enhanced antioxidant and α-glucosidase inhibitory activities.