玉米浆化学成分的分离纯化与结构鉴定

将玉米浆用4倍体积的甲醇进行醇沉，去除无机盐等强极性物质后，浓缩至小体积，用乙酸乙酯萃取，制得乙酸乙酯萃取物。利用硅胶柱色谱、HPLC等分离方法对玉米浆乙酸乙酯萃取物进行分离纯化，得到 23 个化合物。通过理化性质及波谱数据分析鉴定它们结构分别为对羟基苯丙酸（1）、3,4-二羟基-5-甲氧基苯丙酸甲酯（2）、R-2-羟基-3-苯基丙酸甲酯（3）、吲哚-3-乙酸甲酯（4）、2-羟基-3-甲基丁酸（5）、2-羟基-4-甲基戊酸（6）、3,4-二羟基苯丙酸甲酯（7）、二氢阿魏酸甲酯（8）、油酸（9）、对羟基苯乙酸（10）、三油酸甘油酯（11）、R-2-羟基-3-苯基丙酸（12）、环（缬-亮）二肽（13）、环（亮-亮）二肽（14）、环（苯丙-酪）二肽（15）、环（苯丙-缬）二肽（16）、环（亮-异亮）二肽（17）、环（苯丙-苯丙）二肽（18）、环（脯-亮）二肽（19）、尿嘧啶（20）、环（苯丙-甘）二肽（21）、环（苯丙-丙）二肽（22）、环（苯丙-丝）二肽（23）。这些化合物以环二肽、酚酸及其酯类为主，除化合物9以外，其余成分均为首次从玉米浆中分离得到。

Chemical constituent of separation, purification and structural identification from Corn steep liquor

The corn steep liquor was alcohol-precipitated with 4 times the volume of methanol to remove strong polar substances such as inorganic salts, then concentrated to a small volume, and extracted with ethyl acetate to obtain an ethyl acetate extract. The ethyl acetate extract of corn steep liquor was separated and purified by silica gel column chromatography, HPLC and other separation methods, and 23 compounds were obtained. Through physical and chemical properties and spectral data analysis, their structures are identified as p-hydroxybenzene propanoic acid (1), 3,4-dihydroxy-5-methoxyphenylpropyl methyl ester (2), R-2- hydroxy-3-phenylpropanoate (3), methyl indol-3-ylacelate (4), 2-hydroxy-3-methylbutanoic acid (5), 2-hydroxy-4-methyl pentoic acid (6), methyl 3, 4-dihydrophenylpropionate (7), dihydroferulic acid methyl ester (8), oleic acid (9), p-hydroxyphenlacetic acid (10), glycerol trioleate (11), R-2-hydroxy-3-phenylpropanoic acid (12), cyclo (Leu-Leu) (13), cyclo (Val-Leu) (14), cyclo (Phe-Tyr) (15), cyclo (Phe-Val) (16), cyclo (Leu-Ile) (17), cyclo (Phe-Phe) (18), cyclo (Pro-Leu) (19), uracil (20), cyclo (Pro-Gly) (21), cyclo (Pro-Ala) (22), cyclo (Pro-Ser) (23). These compounds are mainly cyclic dipeptides, phenolic acids and their esters. Except for compound 9, the other components are all isolated from corn steep liquor for the first time.