单针藻的化学成分及其体外抗菌、抗氧化活性研究

Study on Chemical Compounds and in vitro Antibacterial and Antioxidant Activities of Monoraphidium dybowskii

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(IC_(50))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/m L内,IC_(50)在22.02~71.01μg/m L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. dybowsldi were extracted with aether petrolei, ethyl acetate and n-butyl alcohol. The ethyl acetate extract was separated from M. dybowsldi 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 （SH）-furanone. MIC of compounds 3-6 were 10-500 μg/mL, and IC50 ranged 22.02-71.01 pg/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.