Oku Tsuneyuki, Yamada Mai, Nakamura Mariko, Sadamori Naoki, Nakamura Sadako
Graduate School of Human Health Science, Siebold University of Nagasaki, Japan.
Br J Nutr. 2006 May;95(5):933-8. doi: 10.1079/bjn20061746.
The inhibitory effect on human and rat intestinal disaccharidase by the extractive from the leaves of Morus alba (ELM) containing 0.24 % 1-deoxynojirimycin equivalent and its inhibitory activities were investigated by the modified Dahlqvist method. In the presence of 1000-fold diluted ELM solution, the sucrase activity of four human samples was inhibited by 96 % and that of maltase and isomaltase by 95 and 99 %, respectively. The activities of trehalase and lactase were inhibited by 44 and 38 %, respectively. The human disaccharidase activities varied from sample to sample because the samples were obtained from different resected regions after surgery. However, the ratio of the inhibitory effect for sucrase, maltase, isomaltase, trehalase and lactase was very similar among the four samples, and also that of resembled rat intestinal disaccharides. The inhibitory constant of the 1-deoxynojirimycin equivalent for sucrase, maltase and isomaltase was 2.1 x 10(-4), 2.5 x 10(-4) and 4.5 x 10(-4) mm, respectively, and these inhibitory activities were shown, using rat brush border membrane vesicles, to be competitive. These results demonstrate that digestion is inhibited when an appropriate amount of ELM is orally ingested with sucrose or polysaccharide in man. When ELM was orally administered in a sucrose solution to fasted rats, the elevation in blood glucose was significantly suppressed, depending on the concentration of ELM given. These results suggest that ELM could be used as an ingredient in health foods and in foods that help to prevent diabetes.
采用改良的达尔奎斯特方法，研究了含有0.24% 1-脱氧野尻霉素当量的桑树叶提取物（ELM）对人和大鼠肠道二糖酶的抑制作用及其抑制活性。在1000倍稀释的ELM溶液存在下，4份人样品的蔗糖酶活性被抑制了96%，麦芽糖酶和异麦芽糖酶活性分别被抑制了95%和99%。海藻糖酶和乳糖酶活性分别被抑制了44%和38%。由于样品是从手术后不同的切除部位获得的，所以人二糖酶活性因样品而异。然而，这4份样品中蔗糖酶、麦芽糖酶、异麦芽糖酶、海藻糖酶和乳糖酶的抑制作用比例非常相似，与大鼠肠道二糖酶的情况也相似。1-脱氧野尻霉素当量对蔗糖酶、麦芽糖酶和异麦芽糖酶的抑制常数分别为2.1×10⁻⁴、2.5×10⁻⁴和4.5×10⁻⁴mm，并且使用大鼠刷状缘膜囊泡显示这些抑制活性具有竞争性。这些结果表明，当人在摄入蔗糖或多糖时口服适量的ELM，消化会受到抑制。当在蔗糖溶液中给禁食大鼠口服ELM时，血糖升高会根据给予的ELM浓度而显著受到抑制。这些结果表明，ELM可作为保健食品和有助于预防糖尿病的食品的一种成分。
