超微粉碎-微波双水相萃取红花龙胆中环烯醚萜苷类

Ultramicro-pulverization and Micowave-assisted Extraction of Iridoid Glycoside from Gentiana rhodantha Franch.

摘要:

以红花龙胆全草为原料，采用超微粉碎和微波控温辅助双水相法提取了其中的环烯醚萜苷类。通过单因素实验和正交实验确定了最佳提取工艺；考察了所得环烯醚萜苷类的总抗氧化作用及其清除1,1-二苯基-2-三硝基苯肼自由基(DPPH)的能力。结果表明，最佳提取工艺为：在30.0 g〔无水乙醇7.8 g(质量分数26%)，磷酸氢二钾(K2HPO4)3.0g (质量分数10%)〕乙醇/K2HPO4双水相体系中，红花龙胆干粉粒度为400目，微波温度(70±1)℃，微波时间110 s，红花龙胆干粉加入量3.5 g，得率为5.48%，相比传统提取工艺热回流得率（3.61%）显著提高。此法能抑制试材内源性水解酶活性且中和植酸（红花龙胆中的酸性物质）来降低溶出环烯醚萜苷类发生聚合反应的几率，有效解决了红花龙胆中环烯醚萜苷类需富集才能检测到的问题；总环烯醚萜苷类的抗氧化能力在0.2~0.6g/L内强于2,6-二叔丁基-4-甲基苯酚(BHT)，对DPPH自由基的清除能力在0.2~1.0g/L内强于BHT。

Abstract:

Iridoid glycosides were extracted from Gentiana rhodantha Franch. by microwave-assisted aqueous two-phase system. The optimal extraction process was determined by single factor experiment and orthogonal experiment. The total antioxidant activity of iridoid glycosides and their ability to scavenge 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radicals were evaluated. The results showed that the optimum extraction conditions were obtained as follows: ethanol 7.8 g (mass fraction 26%) and K2HPO4 3.0 g (mass fraction 10%) in the establishment of 30.0 g ethanol/K2HPO4 aqueous two-phase system, particle size of dry Gentiana rhodantha Franch. powder 400 mesh, microwave extraction temperature 70±1℃, microwave extraction time 110 s and dry powder 3.5 g. Under these conditions, the extraction yield of iridoid glycosides was 5.48%, higher than that obtained by traditional extraction process (3.61%). This method can inhibit the activity of endogenous hydrolase in the test material and neutralize phytic acid (the acid substance in Gentiana rhodantha Franch.) to reduce the polymerization of dissolved iridoid glycosides, which effectively solves the problem that the iridoid glycosides in Gentiana rhodantha Franch. must be enriched to be detected. Total iridoid glycosides had stronger antioxidant activity than 2,6-di-tert-butyl-4-methylphenol (BHT) in the range of 0.2~0.6 g/L, and stronger scavenging activity to DPPH radicals than BHT in the range of 0.2~1.0 g/L.