木榄花萼缩合单宁制备花青定及抗氧化能力研究

Preparation and Antioxidant Activity of Cyanidin from Condensed Tannins Extracted from Calyx of Bruguiera gymnorrhiza

利用MALDI-TOF MS分析了红树植物木榄花萼缩合单宁的结构单元组成类型、平均聚合度和平均分子质量。并以木榄花萼缩合单宁为原料,通过HCl-正丁醇法酸解反应制备了花青定粗产品,同时测定了花青定粗产品对二苯基苦基苯肼自由基(DPPH.)的清除能力及铁离子还原/抗氧化能力(FRAP)。结果表明:木榄花萼缩合单宁结构单元组成类型主要为儿茶素或表儿茶素,平均聚合度为7.5,平均分子质量为2081.60u;花青定粗产品具有较强的清除自由基能力,DPPH.半数抑制浓度(IC50)为43.889mg/L,并具有较高的FRAP((7.718±0.109)mmol/g)。

Type of structural units, degree of polymerization and mean molecular weight of condensed tannins extracted from calyx of large red mangrove （Bruguiera gymnorrhiza ） were characterized by matrix-assisted laser desorptiotr/ionization time-of-flight mass spectrometry （MALDI-TOF MS）. Crude cyanidin products were prepared from condensed tannins of B. gymnorrhiza by means of butanol/HCl reaction. In addition, the free radical-scavenging activity and antioxidant ability of crude cyanidin products were determined by using 1,1 -diphenyl-2-picrylhydrazyl radical （ DPPH. ） and ferric reducing/antioxidant power （FRAP） model systems respectively. The results showed that cateehin/epicatechin were the structural units occurring in condensed tannins of B. gymnorrhiza. Average degree of polymerization was 7.5, and mean molecular mass was 2 081.60 u. Crude cyanidin products showed a very good DPPH radical scavenging activity （IC50 of 43. 889 mg/L） and ferric reducing/antioxidant ability （ （7. 718 ± 0. 109 ） mmol/g）.