银杏叶中α-葡萄糖苷酶抑制剂的超滤质谱筛选

采用体外酶抑制活性检测方法结合超滤质谱(UF-LC/MS)筛选方法对中药提取物中的α-葡萄糖苷酶抑制剂进行了筛选.以4-硝基苯-α-D-吡喃葡萄糖苷(PNPG)为底物,阿卡波糖为阳性对照药,对5种富含黄酮类化合物的中药提取物进行了α-葡萄糖苷酶抑制活性的初步测定.结果表明,银杏叶具有最强的α-葡萄糖苷酶抑制活性,可作为进一步复筛的对象.利用超滤质谱技术对银杏叶中潜在的α-葡萄糖苷酶抑制剂进行了筛选,从中筛选出4种潜在的α-葡萄糖苷酶抑制剂,并利用液相色谱-串联质谱技术(LC-MSn)对其结构进行了鉴定.本文结果为开发新一代安全有效的降糖药物奠定了基础.

Screening of α-Glucosidase Inhibitors in Ginkgo Biloba Extract Using Ultrafiltration LC-ESI-MSn

In vitro α-glucosidase inhibition assays and ultrafiltration liquid chromatography coupled to electrospray ionization tandem mass spectrometry(ultrafiltration LC-ESI-MSn) were combined to screen α-glucosidase inhibitors from ginkgo biloba extract. The enzyme inhibition studies were carried out spectrophotometrically in a 96-well microplate reader. Using 4-nitrophenyl α-D-glucopyranoside(PNPG) as the substrate and acarbose as a positive control, α-glucosidase inhibitory activity of the five kinds of Chinese herb extracts which rich in flavonoids were determined, the results showed that the ginkgo biloba extract has the strongest the α-glucosidase inhibitory activity. Ultrafiltration LC-ESI-MSn was used to screen and identify α-glucosidase inhibitors from ginkgo biloba extract. As a result, four compounds were identified as α-glucosidase inhibitors in the ginkgo biloba extract, and their structures were confirmed to be quercetin, apigenin, kaempferol and isorhamnetin by ESI-MS.