α-Amylase and α-Glucosidase Inhibitors Isolated from Triticum aestivum L. Sprouts

Inhibitory activities of the methanol extract from Triticum aestivum L. sprouts were examined against alpha-amylase and alpha-glucosidase. The active constituents of T. aestivum were isolated by chromatographic techniques and identified as gamma-aminobutyric acid and ferulic acid on the basis of IR and NMR. gamma-Aminobutyric acid and ferulic acid showed the high inhibitory activities with 1050 values of 5.4+/-0.2 and 9.5+/-0.1 mM against alpha-amylase, and 1.4 +/- 0.4 and 4.9 +/- 0.3 mM against alpha-glucosidase. The methoxy group on the hydroxycinnamic acid of ferulic acid derivatives played important functions in the alpha-amylase and alpha-glucosidase inhibitory activities. Based on the IC50 values of nitrite-scavenging activity, ferulic acid (98+/-3.9 mu g/mL) was the most effective constituent, followed by gamma-aminobutyric acid (182 4.2 mu g/mL), sinapic acid (301+/-2.7 mu g/mL), and p-coumaric acid (454+/-2.2 mu g/mL). These results indicate that gamma-aminobutyric acid and ferulic acid could be useful as preventative agents, and possibly therapeutic modalities for the treatment of metabolic diseases.