Abstract: Fruits and vegetables are rich in polyphenolic compounds, in which the ortho phenolic hydroxyl groups are easily oxidized and have a strong ability to capture free radicals such as reactive oxygen species. Thus, these compounds can remove free radicals and quench active oxygen. Nrf2 (NF-E2-related factor 2)/Keap1 (Kelch-like ECH-associated protein 1) signaling pathway is the most important protective signaling pathway to enhance antioxidant status in the body, which plays an important role in cellular antioxidant defense. In the present review, we describe Nrf2/Keap1 signaling pathway and its regulatory mechanism. The dual role of the signaling pathway in cancer chemoprevention and carcinogenesis promotion is discussed as well. The focus of this review is on the molecular mechanism by which serval typical dietary polyphenols affect this dual regulation. We expect that this review will provide a theoretical basis for developing healthy green food products containing plant polyphenols.

Key words: fruits and vegetables, polyphenols, Nrf2/Keap1 signaling pathway, dual role