Leaching properties of antimicrobial Prunus phenols

Prunus callus cultivated in vitro contained the following flavanones: naringenin-7-glucoside (prunin, P), dihydrowogonin-7-glucoside (D) and eriodictyol-7-glucoside (E), in addition to the flavonol dihydrokaempferol-7-glucoside (DK) and a number of diverse flavanols. Both, intracellular diffusion and extracellular leaching of these phenols was studied. Flavanols showed some intracellular diffusion, however, extracellular efflux was only found after pretreatment with abscisic acid (ABA). The other flavonoids were found to leak outside the cells. When prunin (P) was added to the culture medium, it enhanced leakage of all four flavonoids (P, E, D, DK) over a period of 7 weeks. Withdrawal of calcium and iron from the culture media resulted in a several fold leakage of the four flavonoids (P, E, D, DK) over that of controls, indicating a significant membrane disfunction.