阴干过程中黄芪活性成分和抗氧化能力的增长与下降趋势

Dynamic changes of chemical components and antioxidant activities during drying process in the shade

目的新鲜药材尤其是宿根类药材在采后干燥过程中可能会启动抗干旱胁迫机制,从而诱导活性成分的产生和升高。为进一步验证这一假设,对黄芪阴干过程中活性成分和抗氧化能力的动态变化进行了研究。方法采用高效液相色谱法测定了自然阴干过程中,新鲜黄芪根中毛蕊异黄酮、毛蕊异黄酮-7-O-β-葡萄糖苷、黄芪甲苷和黄芪皂苷Ⅱ四种主要成分的含量。同时对阴干过程中药材总酚含量以及相应的抗氧化活性进行了测定。结果在整个阴干过程中四种活性成分及总酚含量均呈现出先升高后降低的变化趋势;同时,清除自由基(DPPH和O-2♂)和抑制脂质过氧化能力在阴干初期均显著升高,后期缓慢降低,但仍然比新鲜样品有显著升高。结论在干燥初期由于黄芪根启动抗干旱胁迫机制,诱导活性成分的大量升高,同时抗氧化能力也大大升高。

Objective The freshly collected medicinal materials especially roots would activize the anti-dehydration physiological process in the post-harvest drying process. For this reason,levels of the related bioactive components would increase during the early phase of dr-ying process. For searching further evidences to approve this hypothesis, dynamic changes of activity components and antioxidant activities in roots of Astragalus membranaceus （Fish.） Bge were determined during drying process. Methods During the drying process in the shade, the contents of calycosin , calycosin-7-O-β-D-glucoside, astragaloside IV and astragaloside Ⅱ in roots of this herb were determined by HPLC, and antioxidant activities of the materials were detected at the same time. Result Both levels of the four components and total phenolics increased markedly in the first 15 d of drying, and then they were degraded gradually. At the same time the radical scavenging include DPPH and O2^- ♂ and the lipid peroxidation inhabition ability increased markedly during the early phase of drying process. Con-clusion This type of dynamic changes of bioactive components was resulted from the possession of anti-drying physiological mechanism in roots of this plant.