1-Deoxynojirimycin (DNJ)

1-Deoxynojirimycin (DNJ) is an alpha-glucosidase inhibitor, most commonly found in mulberry leaves. Although it can be obtained in small quantities by brewing an herbal tea from mulberry leaves, interest in commercial production has led to research on developing mulberry tea higher in DNJ, and on alternate routes of production, such as via Bacillus species.

Mulberry 1-deoxynojirimycin (DNJ), a potent α-glucosidase inhibitor, suppresses postprandial blood glucose, thereby possibly preventing diabetes mellitus. At present, mulberry dry teas are commercially supplied as functional foods in many countries, but these products may not provide an effective dose (6 mg DNJ/60 kg human wt) due to their low DNJ content (about 100 mg/100 g of dry wt). Therefore, development of tea with higher DNJ content is desirable. To do this, we investigated distribution of DNJ content and α-glucosidase inhibitory activity in 35 Thai mulberry varieties.