玉米须总黄酮含量检测络合显色体系的比较

Comparison of Complex Chromogenic Systems for the Detection of Total Flavonoid Content in Corn Silk

摘要:

采用紫外可见分光光度法建立最适合玉米须总黄酮（Corn Silk Total Flavonoids，CSTF）含量检测的络合显色体系。实验选用体积分数60%乙醇为溶剂对CSTF进行提取，并以不同极性溶剂对CSTF进行分级萃取，最终获得正己烷（Normal Hexane，n-Hexane）、乙酸乙酯（Ethyl Acetate Extracts，EAE）和正丁醇（Bormal Butanol，n-BuOH）萃取物。以玉米须中不同类型黄酮为对照品，比较研究NaNO2-Al(NO3)3/AlCl3-NaOH和KAc-Al(NO3)3/AlCl3 四种络合显色体系下乙酸乙酯和正丁醇萃取物中总黄酮含量。同时采用高效液相色谱（High Performance Liquid Chromatography，HPLC）对乙酸乙酯和正丁醇萃取物中黄酮含量进行测定，从而确定最适合的对照品种类和显色体系。结果表明，HPLC法检测乙酸乙酯和正丁醇中黄酮含量分别为83.45%和57.36%，经比较研究发现，与HPLC法检测总黄酮含量最接近的是以芦丁为标准品的KAc-Al(NO3)3络合显色体系。综上所述，KAc-Al(NO3)3 络合显色体系是玉米须和各萃取物总黄酮含量检测的最佳方法，该方法检测CSTF提取液黄酮含量为1.08%。该方法操作简便、准确度高，可为玉米须黄酮类物质的开发利用和质量管控提供依据。

Abstract:

UV-visible spectrophotometry was employed to establish the most suitable complex chromogenic system for detecting corn silk total flavonoids (CSTF). CSTF extraction was performed using 60% ethanol as the solvent, and fractional extraction was undertaken using different polar solvents, which gave the normal hexane (n-hexane), ethyl acetate and normal butanol (n-BuOH) extracts. Using different types of corn silk flavonoids as reference standards, comparisons were made with the total flavonoid content of the ethyl acetate and n-BuOH extracts under the NaNO2-Al(NO3)3/AlCl3-NaOH and KAc-Al(NO3)3/AlCl3 complex chromogenic systems. High-performance liquid chromatography (HPLC) was also performed on the flavonoid content of the ethyl acetate and n-BuOH extracts to identify the most suitable reference standard and chromogenic system.The flavonoid content of the ethyl acetate and n-BuOH extracts detected by HPLC was 83.45% and 57.36%, respectively. The comparative results indicated that the KAc-Al(NO3)3 complex chromogenic system with rutin as the reference standard was the closest to the CSTF detected by HPLC. In conclusion, the KAc-Al(NO3)3 complex chromogenic system was the best method for quantifying the total flavonoid content in corn silk and in each extract, and the flavonoid content of CSTF extract detected using this method was 1.08%. Therefore, this is a simple and accurate technique that can serve as a basis for the development, utilization and quality control of corn silk flavonoids.