title: The berry constituents quercetin, kaempferol, and pterostilbene synergistically attenuate reactive oxygen species: involvement of the Nrf2-ARE signaling pathway.
abstract: Quercetin, kaempferol, and pterostilbene are abundant in berries. The anti-oxidative properties of these constituents may contribute to cancer chemoprevention. However, their precise mechanisms of action and their combinatorial effects are not completely understood. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) regulates anti-oxidative stress enzymes and Phase II drug metabolizing/detoxifying enzymes by binding to antioxidant response element (ARE). This study aimed to investigate the anti-oxidative stress activities of quercetin, kaempferol, and pterostilbene individually and in combination, as well as the involvement of the Nrf2-ARE signaling pathway. Quercetin, kaempferol, and pterostilbene all exhibited strong free-radical scavenging activity in the DPPH assay. The MTS assay revealed that low concentration combinations we tested were relatively non-toxic to HepG2-C8 cells. The results of the DCFH-DA assay and combination index (CI) indicated that quercetin, kaempferol, and pterostilbene attenuated intracellular reactive oxygen species (ROS) levels when pretreated individually and had synergistic effects when used in combination. In addition, the combination treatment significantly induced ARE and increased the mRNA and protein expression of Nrf2-regulated genes. Collectively, our study demonstrated that the berry constituents quercetin, kaempferol, and pterostilbene activated the Nrf2-ARE signaling pathway and exhibited synergistic anti-oxidative stress activity at appropriate concentrations.
authors.affiliation: Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Constance Lay Lay
authors.initials: CL
authors.lastname: Saw
authors.affiliation: Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Graduate Program in Pharmaceutical Sciences, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Graduate Program in Pharmaceutical Sciences, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Anne Yuqing
authors.initials: AY
authors.lastname: Yang
authors.affiliation: Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Graduate Program in Pharmaceutical Sciences, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Ximena
authors.initials: X
authors.lastname: Paredes-Gonzalez
authors.affiliation: Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Graduate Program in Cellular and Molecular Pharmacology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Christina
authors.initials: C
authors.lastname: Ramirez
authors.affiliation: Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Pung
authors.affiliation: Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA. Electronic address: kongt@pharmacy.rutgers.edu.
authors.forename: Ah-Ng Tony
authors.initials: AN
authors.lastname: Kong
mesh_terms: D061745:Antioxidant Response Elements / Q000187:drug effects; D000975:Antioxidants / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005638:Fruit / Q000737:chemistry; D005786:Gene Expression Regulation; D056945:Hep G2 Cells; D006801:Humans; D044949:Kaempferols / Q000494:pharmacology*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D064209:Phytochemicals / Q000494:pharmacology; D011794:Quercetin / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013267:Stilbenes / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D044949:Kaempferols; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D064209:Phytochemicals; D017382:Reactive Oxygen Species; D013267:Stilbenes; C107773:pterostilbene; C006552:kaempferol; D011794:Quercetin
keywords: Antioxidant response element (ARE); Kaempferol; Nuclear factor (erythroid-derived 2)-like 2 (Nrf2); Pterostilbene; Quercetin; Reactive oxygen species