苦瓜皂甙的分离以及PTP1B抑制活性

Isolation of the saponins from Momordica charantia and their PTP1B inhibition activity

通过溶剂萃取、大孔树脂D-101去杂、正相硅胶柱粗分、ODS反相硅胶柱反复分离纯化、薄层色谱检测,从苦瓜中分离出5种化合物.借助于ESI-MS、IR、13C NMR、1H NMR、DEPT-NMR等波谱技术,对这5种化合物进行结构鉴定.结果表明,此5种化合物都属于皂甙类,其中化合物A是甾体皂甙,其余4种为四环三萜葫芦烷皂甙.这5个化合物分别为:A为α-菠甾醇-3-O-β-D-吡喃葡萄糖甙;B为19(R)-羰基-25-二甲氧基-5β-葫芦烷-6,23-二烯-3β,25-羟基-5-19环氧酯-3-O-β-D-吡喃葡萄糖甙;C为葫芦烷-5-烯-3β,22,23,24,25-五羟基-3-O-3-β-D-吡喃葡萄糖(1→6)-D-吡喃葡萄糖甙(苦瓜素A);D为葫芦烷-5,23-二烯-3β,7,25-三羟基-9-醛基-7-O-β-D-吡喃葡萄糖甙(苦瓜素L);E为葫芦烷-5,23-二烯-3β,7-二羟基-9-醛基-25-甲氧基-7-O-β-D-吡喃葡萄糖甙(苦瓜素K).5种化合物进行PTP1B抑制活性筛选试验,结果表明,这5种皂甙单体中,化合物D和化合物E对PTP1B没有抑制活性,化合物A、B、C对PTP1B有不同程度的抑制活性,其中抑制活性大小为化合物A>化合物C>化合物B.

Five compounds were isolated from Momordica charantia L through the absorption of macroporous resin, silica gel column chromatography, reversed-phase silica gel column chromatography and detection of thin-layer chromatography （TLC）. The structures of the compounds were characterized through the spectral technology including ESI-MS and NMR. They are α-spinasterol-3-O-β-D-glucopyranoside （A）, 19 R）-carbonyl-25-dimethoxy-5β-5, 19- epoxycucrbita-6, 23-dien-3β-ol-3-O-β-D-glucopyranoside B ）, momordicoside A （ C ）, momordicoside L （D）, and momordicoside K （E）, respectively. The hypoglycemic activities of these five compounds were tested by using PTP1B （protein tyrosine phosphatase）. The results indicated that the compounds D and E have not inhibition effect on PIP1B but the compound A, B and C have the inhibition effect. The sequence of inhibition activities is A〉C〉B.