单针藻的化学成分及其体外抗菌、抗氧化活性研究

摘要

目的：研究单针藻的化学成分，并对其中分离出的化合物进行体外抗菌、抗氧化活性考察。方法：对单针藻乙醇提取物经石油醚、乙酸乙酯和正丁醇萃取，利用硅胶柱色谱、高效液相色谱、气相色谱-质谱法对单针藻乙酸乙酯部位萃取物进行分离和化学成分分析，并根据理化性质和核磁共振谱等分析鉴定化合物的结构；对分离出的4种化合物分别采用刃天青法测定其对铜绿假单胞菌、白色念珠菌、枯草芽孢杆菌、大肠埃希菌的最低抑菌浓度（MIC），1，1-二苯基-2-苦基-肼基（DPPH）法测定自由基清除率[以半数清除浓度（IC50）计]、亚铁还原能力法（以FRAP值计）测定总还原能力。结果：从单针藻乙酸乙酯萃取部位的E4、E5段分离得到化合物1～6，分别被鉴定为豆甾醇、邻苯二甲酸二丙酯、3-吲哚甲酸、黑麦草素、黑麦草内脂、5-羟基-3，4-二甲基-5-戊基-2（5H）-呋喃酮；化合物3～6的MIC在10～500µg/mL内，IC50在22.02～71.01µg/mL内，FRAP值在（62.04±5.36）～（281.22±8.3）µmol/L内。结论：单针藻含有多种脂类和烷酸类物质，具有一定的体外抗菌、抗氧化活性。%OBJECTIVE:To study chemical compounds of Monoraphidium dybowskii,and to investigate the in vitro antibacte-rial and antioxidant activities of isolated compounds. METHODS:The ethanol extract of M. dybowskii were extracted with aether petrolei,ethyl acetate and n-butyl alcohol. The ethyl acetate extract was separated from M. dybowskii and chemical components were analyzed by sillica gel column chromatogram,HPLC and GC-MS. Their structures were identified according to physicochemi-cal properties and NMR. MIC of 4 isolated compounds to Pseudomonas aeruginosa,Candida albicans,Bacillus subtilis and Esche-richia coli were determined by resazurin disc test. Free radical scavenging rate(concluated by IC50)and reducing capacity were mea-sured by 1,1-diphenyl-2-picryl-diazanyl (DPPH) and ferric reducing antioxidant power (FRAP) assay. RESULTS:Compounds 1-6 were obtained from E4 and E5 segments of ethyl acetate extract of M. dybowskii,and their structures were identified as stigmas-terol,diisonoyladipate,indole-3-carboxylic acid,(+)-epiloliolide,(-)-loliolide,5-hydroxy-3,4-dimethy-5-pentyl-2(5H)-furanone. MIC of compounds 3-6 were 10-500 µg/mL,and IC50 ranged 22.02-71.01 µg/mL;FRAP ranged (62.04 ± 5.36)-(281.22 ± 8.3) µmol/L. CONCLUSIONS:M. dybowskii contains multiple lipid and alkanoic acid,and possesses certain in vitro antibacterial and antioxidant activities.