Rapid separation of lactucin and lactucopicrin from Cichorium glandulosum by medium-pressure preparative liquid chromatography and quantitative analyses by high-performance thin-layer chromatography

Medium-pressure preparative liquid chromatography (MPPLC) was used to isolate and prepare lactucin and lactucopicrin from the whole herb of Cichorium glandulosum. After extracting the methanolic extract of the whole plant with petroleum ether and ethyl acetate several times to obtain ethyl acetate extract, the crude products, namely, lactucin and lactucopicrin were separated using MPPLC and thin-layer chromatography (TLC) tracking, and their purity rates reached more than 80%. The qualitative and quantitative analyses of lactucin and lactucopicrin were carried out by high-performance thin-layer chromatography (HPTLC) on the whole herb of C. glandulosum. The contents of lactucin and lactucopicrin were determined by scanning at 256 nm in the whole herb of C. glandulosum. The R_F values of lactucin and lactucopicrin were 0.42 ± 0.05 and 0.65 ± 0.05 with linear ranges of 0.498–2.988 and 0.499–2.994 μg/band, respectively. The correlation coefficients were 0.9938 and 0.9946, respectively, thereby showing a good linear relationship. The average recoveries were 99.96% and 99.52%, and the relative standard deviations (RSDs) were 2.49% and 2.45%, respectively. The crude products, namely, lactucin and lactucopicrin, can be isolated with high purity from the whole herbs of C. glandulosum by MPPLC. The lactucin and lactucopicrin contents of C. glandulosum can be determined rapidly and accurately by HPTLC.