Pharmacokinetics, Tissue Distribution, and Druggability Prediction of the Natural Anticancer Active Compound Cytisine N-Isoflavones Combined with Computer Simulation.

Cytisine N-methylene-(5,7-dihydroxy-4'-methoxy)-isoflavone (CNF2) is a new compound isolated from the Chinese herbal medicine Sophora alopecuroides. Preliminary pharmacodynamic studies demonstrated its activity in inhibiting breast cancer cell metastasis. This study examined the pharmacokinetics, absolute bioavailability, and tissue distribution of CNF2 in rats, and combined computer-aided technology to predict the druggability of CNF2. The binding site of CNF2 and the breast cancer target human epidermal growth factor receptor-2 (HER2) were examined with molecular docking technology. Next, ACD/Percepta software was used to predict the druggability of CNF2 based on the quantitative structure-activity relationship (QSAR). Finally, a simple and effective HPLC method was used to determine plasma pharmacokinetics and tissue distribution of CNF2 in rats. Prediction and experimental results show that compared with the positive control HER2 inhibitor SYR127063, CNF2 has a stronger binding affinity with HER2, suggesting that its efficacy is stronger; and the structure of CNF2 complies with the Lipinski's Rule of Five and has good drug-likeness. The residence time of CNF2 in rats is less than 4 h, and the metabolic rate is relatively fast; But the absolute bioavailability of CNF2 in rats was 6.6%, mainly distributed in the stomach, intestine, and lung tissues, where the CNF2 contents were 401.20, 144.01, and 245.82 µg/g, respectively. This study constructed rapid screening and preliminary evaluation of active compounds, which provided important references for the development and further research of such compounds.