Effects of Saint John's Wort and Vitamin E on Breast Cancer Chemotherapeutic Agents

摘要

The purpose of this research project is to better understand the interaction of dietary supplements with cancer chemotherapeutic drugs. This information may be useful to decrease the toxicity and increase the effectiveness of chemotherapy. The scope off the research involves in vivo assessments of nutritional supplement-chemotherapeutic drug interactions and in vitro studies of the mechanisms of nutraceutical-chemotherapeutic drug interactions. Neither low or high vitamin E supplements nor St. John's wort significantly changed the rodent LD50 for doxorubicin, docetaxel or cyclophosphamide. Low dose vitamin E supplementation was associated with higher nadir white cell counts after docetaxel and a smaller drop in white count after cyclophosphamide in rats. Neither vitamin E nor St. John's wort supplementation modified rodent hepatic mitochondrial DNA changes caused by docetaxel or doxorubicin. There was no effect of vitamin E or St. John's wort on doxorubicin pharmacokinetics. In women with breast cancer, the drop in neutrophil count after chemotherapy was less in women taking dietary supplements versus no supplements, and in those taking multivitamins or vitamin E. Our studies suggest that dietary supplements such as vitamin E may reduce the bone marrow toxicity in both rodents and humans associated with some cancer chemotherapeutic agents used to treat breast cancer.