Background: A search for inhibitors of multidrug resistance (MDR)-associated protein 1 (MRP1) was performed among the compounds isolated from Euphorbia species, plants traditionally used in folk medicine.
Materials and methods: Fifteen compounds with terpenic or phenolic structures (macrocyclic and polycyclic diterpenes, coumarins, stilbenes and flavonoids) were isolated from the methanol extracts of Euphorbia lagascae and Euphorbia tuckeyana or obtained by derivatization. A functional test based on measuring the efflux of fluorescent MRP1 substrate (BCECF) from human erythrocytes was employed.
Results: Effective MRP1 inhibitors were identified among the stilbenes (piceatannol and its derivatives) and the flavonoids (aromadendrin, naringenin and its derivatives).
Conclusion: Euphorbia species constitute a promising source of multidrug resistance modulators.