甘草炒制过程中主要成分的含量变化及转化规律分析

目的:研究甘草炒制过程中8个主要化学成分的含量变化及转化规律。方法:建立HPLC同时测定甘草中芹糖甘草苷、甘草苷、芹糖异甘草苷、异甘草苷、甘草素、异甘草素、甘草酸和甘草次酸含量的方法,并比较炒制前后8个成分含量的变化情况。色谱条件为Waters Symmetry?C18色谱柱(4.6 mm×250 mm,5μm),流动相乙腈(A)-0.05%磷酸水溶液(B)梯度洗脱(0~9 min,19%~25%A;9~18 min,25%~34%A;18~38 min,34%~51%A;38~58 min,51%~89%A),流速1 mL·min^-1;检测波长320 nm(0~16 min),276 nm(16~25 min),370 nm(25~28 min),254 nm(28~58 min);进样量10μL,柱温30℃。结果:甘草炒制后,3个以二氢黄酮为母核的成分含量总体呈下降趋势;3个以查耳酮为母核的成分含量呈上升趋势;三萜类成分甘草酸变化不明显,甘草次酸略呈上升趋势。当单体加热温度达130℃时,二氢黄酮类与查耳酮类成分均可发生互为异构化反应,该反应随温度升高而加剧。当加热温度升高到180℃时,黄酮苷类成分还可发生苷键断裂(芹糖异甘草苷为130℃),逐渐转化为相应的次级苷及苷元;甘草酸苷键同样也可断裂(150℃),生成甘草次酸。结论:甘草炒制过程中化学成分的变化是复杂的,除了所观察到的异构化反应和苷键裂解外,可能还存在着其他复杂反应,各化合物最终含量的高低受炒制时间、炒制温度、化合物自身稳定性等因素影响。

Analysis on Content Change and Transformation Rule of Main Characteristic Components in Stir-frying Process of Glycyrrhizae Radix et Rhizoma

Objective:To study on the content change and transformation rule of eight main characteristic components in stir-frying process of Glycyrrhizae Radix et Rhizoma.Method:The contents of liquiritin apioside,liquiritin,isoliquiritin apioside,isoliquiritin,liquiritigenin,isoliquiritigenin,glycyrrhizic acid and glycyrrhetinic acid in Glycyrrhizae Radix et Rhizoma were determined simultaneously by HPLC.The chromatographic conditions were Waters Symmetry?C18 column(4.6 mm×250 mm,5μm),and the mobile phase of acetonitrile(A)-0.05%phosphoric acid solution(B)for gradient elution(0-9 min,19%-25%A;9-18 min,25%-34%A;18-38 min,34%-51%A;38-58 min,51%-89%A),the flow rate of 1 mL·min^-1,the detection wavelengths at 320 nm(0-16 min),276 nm(16-25 min),370 nm(25-28 min),254 nm(28-58 min),the injection volume of10μL and the column temperature at 30℃.Result:After stir-frying,the total content of three components with dihydroflavone as mother nucleus was decreased,while the total content of three components with chalcone as mother nucleus showed an upward trend,the content change of glycyrrhizic acid was not obvious,but glycyrrhetinic acid content showed a slight upward trend.When the monomer heating temperature reached 130℃,dihydroflavones and chalcones could be isomerized with each other,and with the increase of temperature,the isomerization became more obvious.When the heating temperature rose to 180℃(isoliquiritin apioside was130℃),in addition to the isomerization,the glucosidic bond of flavonoid glycosides began to break and gradually transformed into the corresponding secondary glycosides or aglycones.Glucosidic bond of glycyrrhizic acid could also be broken to form glycyrrhetinic acid,which was detected at 150℃.Conclusion:The change of chemical composition is complex during stir-frying process of Glycyrrhizae Radix et Rhizoma,in addition to the isomerization and glucosidic bonds breaking observed in this experiment,there may be other complex reactions.The content of one compound in the herb is affected by many factors during its processing,such as the time and temperature of frying,the stability of the compound itself and so on.