Pungent component capsaicin included in red pepper is expected to have preventive and improving effects against obesity due to its body fat burning effect, but it is limited to the applicability to the food. In order to reduce the pungency, to increase the water solubility and to synthesize enzymatically-hydrolysable derivatives, direct enzymatic transglucosylation of capsaicin was carried out by using several kinds of sugars and carbohydrate-related enzymes. From the reaction mixture containing capsaicin together with α-cyclodextrin and α-cyclodextrin glucanotransferase, three new compounds were isolated. The major compound was identified as capsaicin 4-O-α-D-glucopyranoside (hereafter, capsaicin α-glucoside) and other two were its α-maltoside and α-maltotrioside. Capsaicin α-glucoside was effectively hydrolyzed by yeast α-glucosidase and porcine intestinal α-glucosidase, resulting in the release of capsaicin. This glucoside showed no cytotoxicity on rat small intestinal epithelial cells and a remarkably low level of pungency compared to capsaicin. It is concluded that capsaicin α-glucoside could be formed through one step enzymatic transglucosylation and it has new properties such as low cytotoxicity and less pungency.
