Sección de Bioquímica Médica, Instituto de Medicina Experimental, Facultad de Medicina, Universidad Central de Venezuela Apartado Postal 5058, Caracas, Venezuela.
Fitoterapia. 2010 Dec;81(8):1220-3. doi: 10.1016/j.fitote.2010.08.007. Epub 2010 Aug 18.
Glucose intestinal absorption (GIA) is one of the factors that increase glycemia. Its reduction could be an important factor in decreasing hyperglycemia in diabetic patients. It has been shown that the aqueous extract of Bauhinia megalandra leaves inhibits GIA. In the present study we identified a compound present in the extract of B. megalandra responsible for the biological effect. The methanol extract of B. megalandra leaves was fractionated using different solvents, and high-speed counter-current chromatography yielding two pure compounds identified by (1)H NMR and (13)C NMR as kaempferol 3-O-α-rhamnoside and quercetin 3-O-α-rhamnoside. The first one increased the K(M) without changes in the V(MAX) of GIA. In addition it exerted an additive inhibitory effect, on GIA, when combined with phlorizin. We suggest that kaempferol 3-O-α-rhamnoside is a competitive inhibitor of intestinal SGLT1 cotransporter.
肠道葡萄糖吸收（GIA）是导致血糖升高的因素之一。降低肠道葡萄糖吸收可以有效降低糖尿病患者的高血糖。已有研究表明，羊蹄甲叶的水提物可以抑制肠道葡萄糖吸收。本研究旨在鉴定羊蹄甲叶提取物中导致该生物效应的化合物。利用不同溶剂对羊蹄甲叶甲醇提取物进行分步萃取，高速逆流色谱分离得到两种纯化合物，通过（1）H NMR 和（13）C NMR 鉴定这两种化合物分别为山奈酚 3-O-α-鼠李糖苷和槲皮素 3-O-α-鼠李糖苷。山奈酚 3-O-α-鼠李糖苷增加了 GIA 的 K（M），但没有改变 V（MAX）。此外，当与根皮苷联合使用时，它对 GIA 具有相加抑制作用。我们推测山奈酚 3-O-α-鼠李糖苷是肠道 SGLT1 协同转运蛋白的竞争性抑制剂。
