Yan Renyi, Cao Yangyang, Yang Bin
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
Molecules. 2014 Apr 10;19(4):4409-17. doi: 10.3390/molecules19044409.
Semen Oroxyli, derived from the seed of Oroxylum indicum L., is a commonly used Traditional Chinese Medicine with beneficial effects against several respiratory disorders. Antioxidative flavonoids may be partly responsible for its medicinal functions. The aim of this study was to rapidly determine the antioxidants in Semen Oroxyli based on a HPLC-DPPH method. Four major flavonoids, baicalein-7-O-gentiobioside, baicalein-7-O-glucoside, baicalein, and baicalin, were identified as the active components against DPPH free radicals, which is in accord with the results of our former traditional activity-guided phytochemical study. The oxidative products of the four antioxidant flavonoids were studied in the DPPH spiking HPLC assay, it was suggested that the three active flavonoid glycosides were converted into 5,6-dihydroxy-7-methoxyflavone, which implied that an additional hydroxyl at C-6 in 5,7-dihydroxyflavones plays an important role in the DPPH assay.
木蝴蝶，来源于紫葳科植物木蝴蝶的种子，是一种常用的中药，对多种呼吸系统疾病有治疗作用。抗氧化黄酮类化合物可能是其药用功能的部分原因。本研究的目的是基于高效液相色谱-二苯基苦味酰基自由基（HPLC-DPPH）法快速测定木蝴蝶中的抗氧化剂。四种主要黄酮类化合物，黄芩苷-7-O-龙胆二糖苷、黄芩苷-7-O-葡萄糖苷、黄芩素和黄芩苷，被鉴定为抗DPPH自由基的活性成分，这与我们之前传统活性导向的植物化学研究结果一致。在DPPH加标HPLC分析中研究了这四种抗氧化黄酮类化合物的氧化产物，结果表明三种活性黄酮糖苷转化为5,6-二羟基-7-甲氧基黄酮，这意味着5,7-二羟基黄酮C-6位上额外的羟基在DPPH分析中起重要作用。
