Conditions of Prooxidant Activity of Cistus and Pomegranate Polyphenols in V79 Cell Cultures.

Polyphenol rich extracts obtained from cistus herb (Cistus incanus L.) and pomegranate peels (Punica granatunm L.) added at high concentrations (25-100 pg/mL) to V79 (Chinese hamster lung fibroblast) cell cultures, markedly increased intracellular level of ROS (reactive oxygen species). Also in cells exposed to the exogenous oxidant - H₂0₂, [100 μM, 30 min., 37'C] intracellular ROS level was augmented, although to a lower extent than in resting cells not exposed to H₂0₂. Additionally, cistus and pomegranate extracts at high concentration (25-100 μg/mL) inhibited the P-gp protein efflux function in V79 cell cultures. Both pro-oxidant activity of polyphenols at high concentrations and their ability to decrease efflux function of P-gp (cellular multidrug resistance protein) could be exploited for improving anticancer adjuvant therapy.