5,6-O-苯乙烯基亚甲基-L-抗坏血酸的合成及其清除自由基和抗菌性能研究

Synthesis,free-radical scavenging ability and anti-microbial activity of 5,6-O-styrylmethylene-L-ascorbic acid

在对甲苯磺酸为催化剂,N,N-二甲基乙酰胺为溶剂,环己烷为带水剂的体系中,肉桂醛与L-抗坏血酸加热回流得到标题化合物,产率41%。1HNMR的数据表明,产物为两个非对映异构体组成的混合物。用分光光度法研究了产物清除羟基自由基、超氧阴离子自由基和DPPH自由基的能力。结果表明,当受试物的物质的量浓度相同时,产物清除上述3种自由基的能力与L-抗坏血酸基本相当,略比TBHQ强。用MTT法测试了产物对大肠杆菌、枯草芽孢杆菌和铜绿假单胞菌的抗菌作用。结果表明,产物的抑菌活性相当于或略高于肉桂醛,比L-抗坏血酸更强。

A novel ascorbic acid acetal, 5,6-O-styrylmethyl- ene-L-ascorbic acid,was synthesized by refluxing cinnamaldehyde（1.32 g, 10 mmol） and L-ascorbic acid （2.87 g, 15 mmol） in the presence of p-toluene sulfonic acid （0. 19 g, 1 mmol） used as the catalyst, N, N-dimethyl acetamide （8 mL） used as the solvent and cyclohexane （8 mL） used as the water-carrying agent for 2.5 b in 41% yield. 5,6-0- styrylmethylene-L-ascorbic acid was obtained as a mixture of two diastereomers in a molar ratio of 9：1 based on the ^1 HNMR spectroscopic analysis. The scavenging activity of 5,6-O-styrylmethylene-L-ascorbic acid on removing hydroxyl free-radical,superoxide anion free-radical and DPPH free-rad- ical was tested,and compared with that of L-ascorbic acid and TBHQ by spectrophotometry. It was found that the scavenging activity of 5,6-O-styrylmethylene-L-ascorbic acid was stronger than that of TBHQ,and was almost equal to that of L-ascorbic acid, when the molar concentration of the tested samples was the same. The anti-microbial activity of 5,6-O-styrylmethyl- ene-L-ascorbic acid was investigated by MTT assay. Minimal inhibitory concentration （MIC） data showed that 5,6-O- styrylmethylene-L-ascorbic acid had significant inhibition effect on the growth of Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa.