Morus alba has been used for centuries in Japan as a tea infusion. Morus alba contains DNJ and some of its derivatives, which are well known as a-glucosidase inhibitors, as shown in Fig. 1 (Asano et al, 1994). D-glucose analogs such as voglibose, miglitol and acarbose, with nitrogen-in-rings, have been used for the treatment of DM (Drent et al, 2002; Raimbaud et al, 1992; Yasuda et al, 2003).
1-deoxynojirimycin Fagomine Iso-fagomine 1,4-dideoxy-1,4- 1,4-dideoxy-1,4-
(1,2-dideoxynoiirimyciri) imino-D-arabinitol imino-D-ribitol
Fig. 1. Chemical structures of components of the extractive from the leaves of Morus alba, 1-deoxynojirimycin and its derivatives
We have clarified that ELM competitively inhibits the activity of sucrase, maltase, and isomaltase using human and rat intestinal homogenates, and significantly suppresses the increment in blood glucose levels, when ELM is administered with sucrose to rats (Oku et al, 2006). In addition, we found that confections with ELM effectively suppress the postprandial blood levels of glucose and insulin in healthy humans (Nakamura M et al, 2009). We suppose that confections with ELM can contribute to the prevention and the quality-of-life for pre-diabetic and diabetic patients.
To prepare the ELM solution, the leaves are extracted with 50% ethanol, and ethanol is removed with a rotary evaporator. ELM used in this study is kindly provided by Toyotama Healthy Food Co., Ltd. (Tokyo, Japan). The original extract solution contains 0.24% DNJ. A small amount of several types of DNJ derivative is measured using liquid chromatography-mass spectrometry (LC-MS). It has been clarified that this extraction is not associated with toxicity or hematologic, blood biochemical, or pathologic abnormalities in rats (Miyazawa et al, 2003).
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