小花杜鹃中两个新的木脂素

研究小花杜鹃(Rhododendron minutiflorum)的化学成分及其α-葡萄糖苷酶抑制活性。采用正相硅胶、ODS、Sephadex LH-20和HPLC等多种色谱技术,从小花杜鹃的95%乙醇提取物中分离得到9个化合物,通过波谱分析和文献数据对比,鉴定其结构分别为rhodominutinan A(1)、rhodominutinan B(2)、3,4-di(4-hydroxy-3-methoxybenzyl)tetrahydrofuran(3)、venkatasin(4)、苔色酸甲酯(5)、苔黑酚羧酸乙酯(6)、2,4-二羟基-3,6-二甲基苯甲酸甲酯(7)、芹菜素(8)、山奈酚(9)。其中化合物1和2为新的木脂素,化合物3~9为首次从小花杜鹃中分离得到。通过α-葡萄糖苷酶抑制剂体外筛选模型评价化合物的潜在降血糖活性,结果表明化合物8和9具有较好的α-葡萄糖苷酶抑制活性,IC₅₀值分别为57.51±6.35、54.70±3.67μM。

Two new lignans from the Rhododendron minutiflorum

To study the chemical constituents and their α-glucosidase inhibitory activity of Rhododendron minutiflorum.Nine compounds were isolated and purified from the 95% ethanol extract of R.minutiflorum by repeated column chromatography such as silica gel, Sephadex LH-20,ODS and HPLC.These chemical structures were identified as rhodominutinan A(1),rhodominutinan B(2),3,4-di(4-hydroxy-3-methoxybenzyl) tetrahydrofuran(3),venkatasin(4),methyl orsellinate(5),ethyl orsellinate(6),methyl 2,4-dihydroxy-3,6-dimethylbenzoate(7),apigenin(8),kaempferol(9) by spectroscopic data analysis and comparison with literatures reported.In addition, compounds 1 and 2 are new lignans, and 3-9 are isolated from the R.minutiflorum for the first time.The in vitro hypoglycemic activity of the obtained compounds was evaluated by the α-glucosidase inhibitor screening method.The results showed that compounds 8 and 9 display moderate inhibitory activity against α-glucosidase with IC₅₀values of 57.51±6.35,54.70±3.67 μM,respectively.