Although linarin possesses diverse pharmacological activities, its poor oral bioavailability has been a concern for further development. The present study aimed to demonstrate the feasibility of improving the oral absorption of linarin in rats with a bioenhancer‒piperine. First, the intestinal permeability of linarin in the presence and absence of verapamil or piperine was investigated using an in situ single-pass rat intestinal perfusion method. A significant increase in the P_eff when co-perfused with verapamil or piperine indicated that piperine effectively inhibited P-glycoprotein mediated efflux of linarin. Then, the pharmacokinetic profiles of linarin in rats after oral administration of linarin (50 mg/kg) alone and in combination with piperine (20 mg/kg) were determined using a validated LC–MS/MS method. The results showed that piperine increased the plasma exposure (AUC) of linarin by 381% along with an increase in the C_max by 346% and the T_max from 0.05 h to 0.2 h. The present study revealed that piperine significantly enhanced the oral absorption of linarin in rats by inhibiting P-glycoprotein mediated cellular efflux during the intestinal absorption and likely simultaneously by inhibiting the metabolism of linarin.

A novel strategy was developed to identify hepatotoxic compounds in traditional Chinese medicines (TCMs). It is based on the exposure of HL-7702 cells to a TCM extract, followed by the identification and further determination of potential hepatotoxic compounds accumulated in the cells by liquid chromatography–tandem mass spectrometry (LC–MS/MS). As a case study, potential hepatotoxic components in Chelidonium majus L. were screened out. Five alkaloids (sanguinarine, coptisine, chelerythrine, protopine, and chelidonine) were identified by LC–MS/MS within 10 min, and their intracellular concentrations were first simultaneously measured by LC–MS/MS with a run time of 4 min. A cell viability assay was performed to assess the cytotoxicity of each alkaloid. With their higher intracellular concentrations, sanguinarine, coptisine, and chelerythrine were identified as the main hepatotoxic constituents in Ch. majus. The study provides a powerful tool for the fast prediction of cytotoxic components in complex natural mixtures on a high-throughput basis.

A novel strategy based on the use of bionic membrane camouflaged magnetic particles and LC–MS was developed to quickly screen the biomembrane-permeable compounds in herbal medicines. The bionic membrane was constructed by bubble-generating magnetic liposomes loaded with NH₄HCO₃ (BMLs). The lipid bilayer structure of the liposomes enabled BMLs to capture biomembrane-permeable compounds from a herbal extract. The BMLs carrying the compounds were then separated from the extract by a magnetic field. Upon heat treatment, NH₄HCO₃ rapidly decomposed to form CO₂ bubbles within the liposomal bilayer, and the captured compounds were released from BMLs and analyzed by LC–MS. Jinlingzi San (JLZS), which contains various natural ingredients, was chosen to assess the feasibility of the proposed method. As a result, nine potential permeable compounds captured by BMLs were identified for the first time. Moreover, an in vivo animal study found that most of the compounds screened out by the proposed method were absorbed into the blood. The study provides a powerful tool for rapid and simultaneous prediction of multiple biomembrane-permeable components.

Lycopodii Herba is a widely used traditional medicinal herb, and contains diverse fascinating alkaloids. In this study, a fast and sensitive LC-MS/MS method for the simultaneous determination of lycodoline, α-obscurine, and N-demethyl-α-obscurine from Lycopodii Herba in rat plasma and brain tissue was developed and validated. Biological samples were extracted via a protein precipitation procedure using methanol as the extraction solvent and Huperzine B as the internal standard. Chromatographic separation was carried out using a Thermo Syncronis-C18 column (50 mm × 2.1 mm, 5 μm) and a gradient mobile phase containing methanol and water with 0.05% formic acid. The three alkaloids were detected by positive electrospray ionization in selective reaction monitoring mode. The selectivity, crosstalk, carryover effect, linearity, accuracy, precision, extraction recovery, matrix effect, and stability of the current method were validated. Then, using the validated method, the plasma pharmacokinetics and brain tissue distribution of the alkaloids in rats were investigated after intragastrical administration of Lycopodii Herba extract. The three alkaloids were shown to be rapidly absorbed into the blood (T_max, 0.79–1.58 h), and then also eliminated rapidly (t_1/2, 1.27–2.24 h). All of them could pass through the blood–brain barrier. The method provides a new research approach to expand preclinical studies of Lycopodii Herba.