油橄榄叶提取物中橄榄苦苷稳定性及对亚铁离子的螯合作用

doi:10.13386/j.issn1002-0306.2013.04.050

油橄榄叶提取物中橄榄苦苷稳定性及对亚铁离子的螯合作用

Stability of oleuropein in olive leaves extracts and its chelating action to ferrous ions

摘要

摘要: 研究了不同光源、pH、温度和时间对油橄榄叶提取物（OLE）中橄榄苦苷稳定性的影响及对亚铁离子的螯合作用。实验结果表明,橄榄苦苷对光较稳定,与酸性环境相比,在碱性条件下易降解;通过TG-DSC图分析可知,在温度为232.3℃下,橄榄苦苷开始发生分解,且分解过程是一个放热过程。橄榄苦苷随着时间的延长,降解率逐渐增大;25℃27d,橄榄苦苷的降解率达95.24%,4℃27d,橄榄苦苷降解率为38.1%,这些降解原因与其含有的β-葡萄糖苷酶有关。在提取液沸腾5min灭酶后,橄榄苦苷在30d内没有降解。此外,通过亚铁离子的螯合实验可知,油橄榄叶提取物对亚铁离子的螯合作用较强,在浓度为1.2mg/mL时,螯合率约为20%,明显低于EDTA（95.24%）的螯合作用。

Abstract: The effect of different light sources, pH, temperature and time on stability of oleuropein was investigated regarding.The chelation of ferrous ions study was carried out as well.The experimental results showed that oleuropein was stable for light.It was degraded more easily under alkali surroundings than acid surroundings.According to TG-DSC analysis, it was found that oleuropein started to decompose at 232.3℃, and it was an exothermic process.With the time prolonging, oleuropein degradation rate increased.Compared with 38.1% at 4℃, it decomposed 95.24% at 25℃ within 27d due to β-glucosidase action insider it.When the enzyme in the extract was boiled to inactivation, oleuropein wouldn't be decomposed in 30d.In addition, in the experiments of chelating ferrous ions, the chelating rate of the extract was about 20% which significantly less than EDTA (95.24%) at concentration 1.2mg/mL.