Chalcones have shown a broad spectrum of biological activities with clinical potential against various diseases. The biological activities are mainly attributed to the presence in the chalcones of the α,β-unsaturated carbonyl system, perceived as a potential Michael acceptor. Chalcones could activate the Kelch-like ECH-associated protein 1 (Keap1)/Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway through a Michael addition reaction with the cysteines of Keap1, which acts as a redox sensor and negative regulator of Nrf2. This modification allows the dissociation of Nrf2 from the cytoplasmic complex with Keap1 and its nuclear translocation. At this level, Nrf2 binds to the antioxidant response element (ARE) and activates the expression of several detoxification, antioxidant and anti-inflammatory genes as well as genes involved in the clearance of damaged proteins. In this regard, the Keap1/Nrf2–ARE pathway is a new potential pharmacological target for the treatment of many chronic diseases. In this review we summarize the current progress in the study of Keap1/Nrf2–ARE pathway activation by natural and synthetic chalcones and their potential pharmacological applications. Among the pharmacological activities highlighted, anti-inflammatory activity was more evident than others, suggesting a multi-target Michael acceptor mechanism for the chalcones involving key regulators of the Nrf2 and nuclear factor- κB (NF-κB) pathways.

The total GSH depletion observed in the substantia nigra (SN) appears to be responsible for subsequent oxidative stress (OS), mitochondrial dysfunction, and dopaminergic cell loss in patients with Parkinson’s disease. A strategy to prevent the OS of dopaminergic cells in the SN may be the use of chemopreventive agents as inducers of endogenous GSH, antioxidant and phase 2 enzymes. In this study, we demonstrated that treatment of the dopaminergic‐like neuroblastoma SH‐SY5Y cell line with sulforaphane (SF), a cruciferous vegetables inducer, resulted in significant increases of total GSH level, NAD(P)H : quinone oxidoreductase‐1, GSH‐transferase and ‐reductase, but not GSH‐peroxidase, catalase and superoxide dismutase activities. Further, the elevation of GSH levels, GSH‐transferase and NAD(P)H:quinone oxidoreductase‐1 activities was correlated to an increase of the resistance of SH‐SY5Y cells to toxicity induced by H₂O₂ or 6‐hydroxydopamine (6‐OHDA). The pre‐treatment of SH‐SY5Y cells with SF was also shown to prevent various apoptotic events (mitochondrial depolarization, caspase 9 and 3 activation and DNA fragmentation) and necrosis elicited by 6‐OHDA. Further, the impairment of antioxidant capacity and reactive oxygen species formation at intracellular level after exposure to 6‐OHDA was effectively counteracted by pre‐treatment with SF. Last, both the cytoprotective and antioxidant effects of SF were abolished by the addition of buthionine sulfoximine supporting the main role of GSH in the neuroprotective effects displayed by SF. These findings show that SF may play a role in preventing Parkinson’s disease.

ATP‐binding cassette (ABC) transporters, in particular P‐glycoprotein (encoded by ABCB1), are important and selective elements of the blood‐brain barrier (BBB), and they actively contribute to brain homeostasis. Changes in ABCB1 expression and/or function at the BBB may not only alter the expression and function of other molecules at the BBB but also affect brain environment. Over the last decade, a number of reports have shown that ABCB1 actively mediates the transport of beta amyloid (Aβ) peptide. This finding has opened up an entirely new line of research in the field of Alzheimer’s disease (AD). Indeed, despite intense research efforts, AD remains an unsolved pathology and effective therapies are still unavailable. Here, we review the crucial role of ABCB1 in the Aβtransport and how oxidative stress may interfere with this process. A detailed understanding of ABCB1 regulation can provide the basis for improved neuroprotection in AD and also enhanced therapeutic drug delivery to the brain.