In this study, the anti-cancer effects of the chemotherapy drug 5-fluorouracil (also known as Fluorouracil, 5-FU or Adrucil) in MDA-MB-453 human breast cancer cells (which overexpress ErbB2) was found to be enhanced by the addition of apigenin to the treatment. Apigenin is a flavone found most abundantly in parsley, celery, bell peppers and Chinese cabbage. Cellular proliferation was observed to be significantly inhibited in cells exposed to 5-fluorouracil plus apigenin, compared with the proliferation in cells exposed only to 5-fluorouracil. Similarly, the level of ErbB2 was found to be unaffected by 5-fluorouracil alone, but was markedly reduced in cells treated with both 5-fluorouracil and apigenin. The authors conclude that 5-fluorouracil acts synergistically with apigenin in inhibiting cell growth and inducing apoptosis through the down-regulation of ErbB2 expression and Akt signaling.

Apigenin and breast cancer treatment

This study confirms the results of other studies that have found that apigenin has anti-cancer activities, especially against estrogen receptor negative (ER-) and HER2-positive breast cancer. It adds the information that apigenin is not only safe to consume during 5-FU chemotherapy regimens such as FAC, but might actually enhance their effectiveness. In addition to its effects in the laboratory, one large Italian population study found that dietary intake of apigenin (among other flavones) was associated with lower risk of breast cancer.

However, apigenin can act both as an estrogen and as an anti-estrogen depending on the dosage, and can actually stimulate the growth of estrogen receptor positive (ER+) breast cancer cells under some circumstances. Apigenin was also found to reduce the cytotoxicity of doxorubicin (Adriamycin) in another study using leukemia cells. This finding indicates that, not surprisingly, apigenin has varying interactions with different types of chemotherapy and cancers and cannot be assumed to be universally beneficial. Based on the available evidence, compared to consuming it as part of foods in the diet, supplementation with apigenin appears to be unwise.