Identification of α-glucosidase inhibitors from black garlic

Abstract

Black garlic has emerged as one of the fastest-growing health food products on the market. It is processed by incubating fresh garlic under high temperature and high humidity conditions. The process causes the changes in characteristics of black garlic such as texture, flavor, nutrient contents, chemical composition and it pharmacological properties, especially antidiabetic activity. In the present investigation, we applied α-glucosidase inhibition guided isolation to identify active compounds. Four compounds named 5-hydroxymethylfurfural (5-HMF), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 4-(hydroxymethyl)phenol and 2-deoxy-ribono-1,4 lactone were isolated. On evaluation against α-glucosidase, HMFCA, 4-(hydroxymethyl)phenol, and 2-deoxy-ribono-1,4 lactone were active against maltase with IC50 values of 18.83 ±0.91, 23.70 ±1.52, and 9.26±0.31 mM respectively. Meanwhile, HMFCA and 4-(hydroxymethyl)phenol were also active against sucrase with IC50 values of 17.42 ±0.84 and 6.78 ±0.17mM, respectively. The kinetic study suggested that HMFCA and 4-(hydroxymethyl)phenol could inhibit the maltase and sucrase by uncompetitive manner. On the other hand, 2-deoxy-ribono-1,4 lactone was identified as a non-competitive inhibitor against maltase.