Macleaya cordata (Willd) R. Br. is a medicinal plant. The most important bioactive compounds of M. cordata are alkaloids that have many biological activities including antifungal, anti‐inflammatory, and antitumor. In this study, an ionic‐liquid‐modified high‐speed counter‐current chromatography method was established to obtain alkaloids from the fruits of M. cordata. The conditions of ionic‐liquid‐modified high‐speed counter‐current chromatography, including solvent systems, the content of ionic liquid (1‐butyl‐3‐methylimidazolium tetrafluoroborate [C4mim][BF4]), and the posttreatment of the ionic liquid, were investigated. Five alkaloids protopine, allocryptopine, sanguinarine, 8‐O‐demethylchelerythrine, and chelerythrine were separated from the extract of the fruits using a high speed counter‐current chromatography with two‐phase solvent system composed of dichloromethane/methanol/0.3 mol/L hydrochloric acid aqueous solution/[C4mim][BF4] (4:2:2:0.015, v/v). Their purities were 96.33, 95.56, 97.94, 96.22, and 97.90%, respectively. The results indicated that a small amount of ionic liquids as modifier of the two‐phase solvent system could shorten the separation time and improve the separation efficiency of the alkaloids from the fruits. The ionic‐liquid‐modified high‐speed counter‐current chromatography would provide a feasible way for highly effective separation of alkaloids from natural products.

BACKGROUND To enhance discovering efficiency of new herbicidal compounds, a strategy for rapidly screening out strongly herbicidal chemical components from natural resources is necessary. RESULTS Seventeen essential oils selected from 14 Eucalyptus species and hybrids were evaluated for their herbicidal activities on annual ryegrass. A feasible strategy was established for rapidly pinpointing the chemicals contributing to strong herbicidal activities without the process of isolation and purification of individual compounds. This strategy was based on gas chromatography–mass spectrometry (GC–MS) coupled with principal component analysis (PCA) and verified by the bioassay results using several individual compounds. Two strong herbicidal compounds trans‐pinocarveol and α‐terpineol were screened out using the strategy. The strong herbicidal activity of trans‐pinocarveol was discovered for the first time. CONCLUSION The established strategy of screening herbicidal compounds from natural resources is simple, feasible and reliable. © 2019 Society of Chemical Industry

A strategy for fast screening of flavonoids in switchgrass and M. micrantha by LC/MS-IT-TOF has been established and applied.

An efficient LC/MS-IT-TOF method to identify ten impurities and fragment pathways in 2C-E tablets was established for the first time.

Label-free fluorescent ionic liquid-functionalized silicon nanoparticles with tunable amphiphilicity for highly sensitive and selective detection of Hg2+ were synthesized.

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