Redox modulation of stress resilience by Crocus sativus L. for potential neuroprotective and anti-neuroinflammatory applications in brain disorders: From molecular basis to therapy.

Recent evidence demonstrates that Crocus sativus L. (saffron) counteracts oxidative stress, mitochondrial dysfunction and neuroinflammation, closely linked to initiation and progression of major brain pathologies. Interestingly, saffron constituents such as crocin, crocetin and safranal can exert antioxidant or toxic effects depending on their endogenous concentration. According to the hormesis principles, at low dose they act as antioxidants in a wide range of brain diseases by upregulating Nrf2 signaling pathway and the expression of vitagenes, such as NAD(P)H-quinone oxidoreductase (NQO1), glutathione transferase (GT), heme oxygenase-1 (HO-1), sirtuin-1 (Sirt1) and thioredoxin (Trx) system. Importantly, neuronal dysregulation of Nrf2 pathway can be a prominent cause of selective susceptibility, under neuroinflammatory conditions, due to the high vulnerability of brain cells to oxidative stress. Here we discuss natural inducers from saffron targeting Nrf2/vitagene pathway for development of new therapeutical strategies to suppress oxidative stress and neuroinflammation and consequently cognitive dysfunction. In this review we also focus on the hormetic effect of saffron active constituents, summarizing their neuroprotective and anti-neuroinflammatory properties, as well as pharmacological perspectives in brain disorders.

Hormesis, cellular stress response, and redox homeostasis in autism spectrum disorders.

In the United States, 1.1-1.5% of children have been diagnosed with autism spectrum disorders (ASD), corresponding to a 30% increase in incidence and prevalence. Social and communication impairments are the main signs and symptoms of ASD, and currently available medications have been ineffective in reducing these core deficits. Observational studies have indicated that children with ASD tend to show improved cognition and behavior after febrile illness, which is associated with alteration of metabolic pathways, leading to cellular stress responses and increased expression of heat shock proteins (Hsps). Sulforaphane and hydroxytyrosol, phytochemicals derived from cruciferous vegetables and extra virgin olive oil, respectively, can induce metabolic effects in cellular stress responses that are similar to those produced by fever. Thus, modulation of endogenous cellular defense mechanisms may be an innovative approach for therapeutic intervention in ASD and other disorders associated with neuroinflammation and neurodegeneration. This Review introduces the hormetic dose-response concept and presents possible mechanisms and applications for neuroprotection. We address the emerging role of Hsps in the neuroprotective network of redox stress-responsive mechanisms and propose the potential therapeutic utility of the nutritional antioxidants sulforaphane and hydroxytyrosol against particular signs and symptoms of ASD. We argue that such research findings must be approached with pragmatism and prudence. It is vital to capitalize on recent and ongoing investments in brain science research and to refine neuroscientific knowledge and capability for more accurate diagnosis and safe, effective, and ethically sound treatment of ASD and other neuropsychiatric spectrum disorders. © 2016 Wiley Periodicals, Inc.

Redox modulation of cellular stress response and lipoxin A4 expression by Hericium Erinaceus in rat brain: relevance to Alzheimer's disease pathogenesis.

BACKGROUND: There has been a recent upsurge of interest in complementary medicine, especially dietary supplements and foods functional in delaying the onset of age-associated neurodegenerative diseases. Mushrooms have long been used in traditional medicine for thousands of years, being now increasingly recognized as antitumor, antioxidant, antiviral, antibacterial and hepatoprotective agent also capable to stimulate host immune responses. RESULTS: Here we provide evidence of neuroprotective action of Hericium Herinaceus when administered orally to rat. Expression of Lipoxin A4 (LXA4) was measured in different brain regions after oral administration of a biomass Hericium preparation, given for 3 month. LXA4 up-regulation was associated with an increased content of redox sensitive proteins involved in cellular stress response, such as Hsp72, Heme oxygenase -1 and Thioredoxin. In the brain of rats receiving Hericium, maximum induction of LXA4 was observed in cortex, and hippocampus followed by substantia Nigra, striatum and cerebellum. Increasing evidence supports the notion that oxidative stress-driven neuroinflammation is a fundamental cause in neurodegenerative diseases. As prominent intracellular redox system involved in neuroprotection, the vitagene system is emerging as a neurohormetic potential target for novel cytoprotective interventions. Vitagenes encode for cytoprotective heat shock proteins 70, heme oxygenase-1, thioredoxin and Lipoxin A4. Emerging interest is now focussing on molecules capable of activating the vitagene system as novel therapeutic target to minimize deleterious consequences associated with free radical-induced cell damage, such as in neurodegeneration. LXA4 is an emerging endogenous eicosanoid able to promote resolution of inflammation, acting as an endogenous "braking signal" in the inflammatory process. In addition, Hsp system is emerging as key pathway for modulation to prevent neuronal dysfunction, caused by protein misfolding. CONCLUSIONS: Conceivably, activation of LXA4 signaling and modulation of stress responsive vitagene proteins could serve as a potential therapeutic target for AD-related inflammation and neurodegenerative damage.