Curcumin (CUR), a natural polyphenol extracted from rhizome of the Curcuma longa L, has received great attention for its multiple potential health benefits as well as disease prevention. For instance, CUR protects against toxic agents acting on the human body, including the nervous system. In detail, CUR possesses, among others, strong effects as an autophagy activator. The present study indicates that CUR counteracts methamphetamine (METH) toxicity. Such a drug of abuse is toxic by disturbing the autophagy machinery. We profited from an unbiased, low variable cell context by using rat pheochromocytoma PC12 cell line. In such a system, a strong protection was exerted by CUR against METH toxicity. This was associated with increased autophagy flux, merging of autophagosomes with lysosomes and replenishment of autophagy vacuoles with LC3, which instead is moved out from the vacuoles by METH. This is expected to enable the autophagy machinery. In fact, while in METH-treated cells the autophagy substrates α-synuclein accumulates in the cytosol, CUR speeds up α-synuclein clearance. Under the effects of CUR LC3 penetrate in autophagy vacuoles to commit them to cell clearance and promotes the autophagy flux. The present data provide evidence that CUR counteracts the neurotoxic effects induced by METH by promoting autophagy.

Neurodegenerative diseases (NDs) are among the leading causes of disability and mortality worldwide and are characterized by multifactorial pathogenesis involving interconnected mechanisms, such as oxidative stress, protein misfolding and aggregation, neuroinflammation, and mitochondrial dysfunction. Dysregulation of transcription factors, governing cellular defense responses, particularly nuclear factor erythroid 2–related factor 2 (Nrf2), a key regulator of antioxidant and proteostatic pathways, plays a critical role in neurodegenerative processes. Currently, available pharmacological treatments for NDs are largely symptomatic, as no disease-modifying therapies exist. Natural bioactive compounds have emerged as promising multi-target agents, demonstrating antioxidant, anti-aggregative, and anti-apoptotic properties, frequently mediated through activation of the Nrf2 signaling pathways. These compounds may represent valuable supportive strategies alongside conventional drug treatments, potentially contributing to the modulation of multiple pathogenic mechanisms. This review summarizes key oxidative stress- and protein aggregation-driven mechanisms underlying Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and Huntington’s disease. It further examines the neuroprotective potential of plant-, fungi-, and marine-derived natural compounds, with particular emphasis on Nrf2 activation. Beyond redox regulation, the broader role of Nrf2 in maintaining proteostasis is discussed. Overall, the review highlights Nrf2-inducing nutraceuticals as promising complementary, multi-target approaches for neuroprotection in NDs.

Primary mitochondrial diseases (PMD) are rare disorders with limited therapeutic options. Coenzyme Q10 (CoQ10) supplementation is widely used, although formulation differences can affect absorption and efficacy. This open-label pilot feasibility trial evaluated a food for special medical purposes (FSMP) containing high-dose CoQ10 (250 mg per capsule) in patients with PMD. Ten patients (mean age: 55.5 ± 8.6 years) were enrolled. Serum/plasma biomarkers, including CoQ10, fibroblast growth factor 21 (FGF21), growth differentiation factor 15 (GDF15), ferric-reducing antioxidant power (FRAP), total sulfhydryl groups (t-SH), and advanced oxidation protein products (AOPP), were assessed at baseline (T0, after ≥30 days of conventional ubidecarenone) and after 30 days of FSMP administration (T1). Fatigue severity scale (FSS) and 5-times sit-to-stand test (5xSST) were evaluated at both timepoints. FSMP was administered at 250 or 500 mg/day. Twenty sex- and age-matched healthy controls were included for CoQ10 comparison. Absolute CoQ10 concentrations remained stable overall at T1, with all patients maintaining levels above 390 ng/mL (100% vs. 60% at T0), although concentrations remained lower than in healthy controls (p < 0.01). Dose-normalized CoQ10 exposure was significantly higher with FSMP versus conventional ubidecarenone (p < 0.001, Cohen’s d = 7.31). FGF21, GDF15, AOPP, and t-SH remained unchanged, whereas FRAP increased at T1 (p < 0.01). No significant changes were observed in 5xSST and FSS. Exploratory analyses indicated inter-individual variability in functional responses. FSMP was associated with higher dose-normalized systemic CoQ10 exposure, more consistent circulating CoQ10, and increased FRAP levels. Its simplified dosing regimen may support long-term adherence. Larger studies are warranted to validate these preliminary findings.

Tinnitus is a multifactorial condition with limited effective treatment options. Natural compounds have been proposed to modulate molecular pathways potentially involved in its pathophysiology, although clinical evidence remains preliminary. This retrospective observational study, conducted without a control group, evaluated 92 patients receiving a multi-compound nutraceutical (4 capsules/day) containing Auricularia auricula-judae, Curcuma longa, Hericium erinaceus, Ganoderma lucidum, Berberis aristata, and Rosa canina. Tinnitus severity was assessed using the Tinnitus Handicap Inventory (THI) at baseline (T0), 1.5 months (T1), and 3 months (T2). Concurrently, hearing thresholds were evaluated at T0 and T2. Patients were stratified into secondary (Group A; N = 48) and primary (Group B; N = 44) tinnitus. THI scores decreased significantly in both groups over time (p 7-point THI reduction). Hearing thresholds remained stable in both groups. A modest correlation between THI and dB variation was observed in Group A at T2 (r = 0.346; p