唐古特白刺果实酚酸类化学成分及α-葡萄糖苷酶抑制活性研究

Study on phenolic acids andα-glucosidase inhibitory activity of Nitraria tangutorum fruit

目的对蒺藜科白刺属植物唐古特白刺Nitraria tangutorum果实中酚酸类成分及α-葡萄糖苷酶抑制活性进行研究。方法采用硅胶柱色谱、MCI色谱及半制备高效液相色谱法等技术对其进行分离纯化,结合NMR和MS等波谱学数据鉴定单体化合物结构,对化合物的蔗糖酶和麦芽糖酶抑制活性进行筛选,并对活性较好的化合物进行蔗糖酶和麦芽糖酶分子对接分析。结果从唐古特白刺果实中分离得到11个化合物,分别鉴定为6’-O-对香豆酰基-α-槐糖(1)、6’-O-对香豆酰基-β-吡喃葡萄糖基-(1-2)-α-甘露糖(2)、4-羟基苯甲酸(3)、香草酸(4)、原儿茶酸甲酯(5)、对香豆酸(6)、咖啡酸(7)、6-O-对香豆酰基-D-半乳糖(8)、反式-4-O-β-D-吡喃喃葡糖基阿魏酸(9)、cynarin(10)、芍药苷(11)。化合物7对蔗糖酶和麦芽糖酶的半数抑制浓度(median inhibition concentration,IC_(50))值分别为809.1和768.5μmol/L,化合物10的IC_(50)值分别为473.3和114.3μmol/L;分子对接显示化合物7对蔗糖酶和麦芽糖酶结合自由能分别为-27.6和-25.5 kJ/mol,化合物10的结合自由能分别为-36.8、-36.4 kJ/mol。结论化合物1和2是新化合物,并分别命名为香豆酰苷A和香豆酰苷B;化合物5、8~10首次从该属植物中分离得到,并且化合物7和10对蔗糖酶和麦芽糖酶都具有较好的抑制活性。

Objective To study the phenolic acids andα-glucosidase inhibitory activity of Nitraria tangutorum fruit.Methods It was separated and purified by silica gel column chromatography,MCI medium pressure chromatography and semi-preparative high performance liquid chromatography.The compound structure was identified by combining NMR and MS spectroscopy data.The inhibitory activities of the compounds on sucrase and maltase were screened,then the compounds with better activities were analyzed by molecular docking with sucrase and maltase.Results Eleven compounds were isolated from juice of N.tangutorum,which were identified as 6’-O-p-coumaroyl-α-sophorose(1),6’-O-p-coumaroyl-β-glucopyranosyl-(1-2)-α-mannopyranose(2),4-hydroybenzoic acid(3),vanillic acid(4),protocatechuic acid methyl ester(5),p-coumarinic acid(6),caffeic acid(7),6-O-p-coumaroyl-D-galactopyranose(8),trans-4-O-β-D-glupyransylferlic acid(9),cynarin(10),and paeoniflorin(11).The IC_(50)values of compound 7 on sucrase and maltose were 809.1 and 768.5μmol/L,respectively,and the IC_(50) values of compound 10 were 473.3 and 114.3μmol/L,respectively.The molecular docking results showed that the binding free energies of compounds 7 and 10against sucrase and maltase were-27.6 and-25.5 kJ/mol,and-36.8 and-36.4 kJ/mol,respectively.Conclusion Compounds 1and 2 are new compounds,and named tanguate A and tanguate B,respectively.Compounds 5,8,9 and 10 are isolated first time from Nitraria,and compounds 7 and 10 have good inhibitory activities on sucrase and maltase.