Activation of anti-oxidant Nrf2 signaling by substituted trans stilbenes

Abstract

Nrf2, which is a member of the cap'n'collar family of transcription factors, is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. The importance of inflammation and oxidative stress in many chronic diseases supports the concept that activation of anti-oxidant Nrf2 signaling may have therapeutic potential. A number of Nrf2 activators have entered into clinical trials. Nrf2 exists in the cytosol in complex with its binding partner Keap1, which is a thiol-rich redox-sensing protein. In response to oxidative and electrophilic stress, select cysteine residues of Keap1 are modified, which locks Keap1 in the Nrf2-Keap1 complex and allows newly synthesized Nrf2 to enter the nucleus. Numerous Nrf2-activating chemicals, including a number of natural products, are electrophiles that modify Keap1, often by Michael addition, leading to activation of Nrf2. One concern with the design of Nrf2 activators that are electrophilic covalent modifiers of Keap1 is the issue of selectivity. In the present study, substituted trans stilbenes were identified as activators of Nrf2. These activators of Nrf2 are not highly electrophilic and therefore are unlikely to activate Nrf2 through covalent modification of Keap1. Dose-response studies demonstrated that a range of substituents on either ring of the trans stilbenes, especially fluorine and methoxy substituents, influenced not only the sensitivity to activation, reflected in EC values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2. The stilbene backbone appears to be a privileged scaffold for development of a new class of Nrf2 activators.

Synthesis of Terminally Fluorinated [7]Helicenes and Their Application to Photochemical Domino Reactions

“…The physical data of compounds 5 , 6 , 1 a , 2 a , 3 a , and 4 a are listed in our previous paper [7] . Compound 7 was prepared using slightly‐modified literature procedures [14] …”

The anti-inflammatory activities of twelve Nigerian medicinal plants: Inhibition of NfkB, activation of Nrf2, and antioxidant content

“…As previously described (Deck et al, 2017), a Nrf2-ARE reporter-Hep G2 stable cell line (BPS Bioscience, San Diego, CA, USA) was grown in a humidified atmosphere at 37 O C in CO 2 (5%)/air (95%). The cells were maintained in MEM medium with Earles balanced salts and L-glutamine (Gibco, Invitrogen, Carlsbad, CA, USA) supplemented with 10% fetal bovine serum (FBS), 1 mM sodium pyruvate, 1% non-essential amino acids, penicillin (100 units/ml), streptomycin (100 µg/ml), and Geneticin (400 µg/ml) to maintain cell selection.…”

Curcumin, Resveratrol and Cannabidiol as Natural Key Prototypes in Drug Design for Neuroprotective Agents

“…In conclusion, the authors highlighted the absence of linearity in the structure-activity relationship (SAR) among all tested compounds, suggesting that not only the nature but also the position of a given substituent is responsible for the antioxidant effect. Moreover, there are other Keap1-independent pathways that could be involved in the Nrf2 activation and, in turn, result in a cascade of cellular changes, which culminate in antioxidant, anti-inflammatory and neuroprotective effects, and that trans-stilbene substituted derivatives could be studied to innovate findings in the drug discovery for NDs [ 159 ].…”