香茅草精油微乳液的构建及其抗氧化活性分析

Preparation of Microemulsion of Cymbopogon citratus (DC) Stapf Essential Oil and Analysis of Antioxidant Activity

摘要:

本研究的目的是构建一种改善香茅草精油在水相环境中应用的微乳体系。以香茅草为原料，采用水蒸汽蒸馏法提取香茅草精油以及GC-MS联用技术对精油成分进行定性分析。通过绘制伪三元相图选择合适的微乳液组分制备香茅草精油微乳液，考察不同表面活性剂、助表面活性剂、Km值、pH值和离子强度等因素对微乳区域面积的影响。最终制备以Tween 80为表面活性剂，无水乙醇为助表面活性剂，去离子水为水相的O/W型香茅草精油微乳液。其理化性质为：pH为6.73±0.02、黏度为15.50±0.11 mPa/s、电导率为108.90±0.21 μs/cm、平均粒径为16.50±0.53 nm。最后，通过用DPPH，ORAC和PSC方法测定及比较香茅草精油与香茅草精油微乳液的抗氧化活性。结果表明，香茅草精油微乳液在水相环境中的抗氧化活性显著优于香茅草精油的效果（p<0.05）。

Abstract:

This study aimed to prepare a microemulsion system that could improve the application of Cymbopogon citratus (DC) Stapf essential oil in aqueous environments. The essential oil was extracted by hydrodistillation and the volatile compounds in the extract (CEO) were analyzed by GC-MS. Pseudo-ternary phase diagrams were constructed to select suitable ingredients for preparation of microemulsions. The effects of surfactants, co-surfactant, Km value, pH value, ionic strength and other factors on the microemulsion existing area in the pseudo ternary diagram were investigated, to prepare a C.EO O/W microemulsion using Tween 80 (surfactant), anhydrous ethanol (co-surfactant), and deionized water ( aqueous phase). Its physicochemical properties were as follows: pH 6.73 ± 0.02, viscosity 15.50 ± 0.11 mPa ? s-1, conductivity 108.90 ± 0.21 μs ? cm-1, and average particle diameter 16.50 ± 0.53 nm. Finally, the antioxidant activities of CEO and CEO microemulsion were determined by DPPH, ORAC and PSC assays. The obtained results showed the antioxidant activity of CEO microemulsion was significantly higher than that of CEO (p < 0.05).