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.
