Ramá Gyöngyössy

Alzheimer’s disease (AD) is characterized by mitochondrial dysfunction, oxidative stress, insulin resistance, and aberrant protein aggregation. Neurodegeneration model with neuronal insulin resistance was induced in SH-SY5Y human neuroblastoma cells by streptozotocin (STZ). We evaluated the neuroprotective effects of resveratrol (RZV) and three structural analogs: oxyresveratrol (OXI), monomethyl resveratrol (MONO), and trimethyl resveratrol (TRI). Mitochondrial function, plasma membrane integrity, oxidative stress) and autophagy were studied by fluorescent assays. Phosphorylated GSK3 levels were measured by ELISA as an indicator of insulin sensitivity. TRI exhibited significant mitochondrial protective effects and strongly induced autophagy. OXI demonstrated excellent antioxidant activity but showed no detectable mitochondrial protective or autophagy-inducing effects. RZV and MONO exhibited moderate antioxidant effects along with strong insulin-sensitizing and autophagy-inducing properties. Insulin sensitivity was most potently restored by RZV (IC₅₀ = 54 pM) and MONO (IC₅₀ = 50 pM), whereas TRI (IC₅₀ = 160 pM) was less potent, and OXI (IC₅₀ = 97 pM) showed moderate potency. Our findings suggest that the neuroprotective effects of resveratrol analogs significantly depend on their molecular structure and that they exert their beneficial effects through distinct mechanisms. This research may contribute to the development of novel, multi-target compounds for the treatment of neurodegenerative diseases.

Background and Objectives: Expansion of white adipose tissue causes systemic inflammation and increased risk of metabolic diseases due to its endocrine function. Resveratrol was suggested to be able to prevent obesity-related disorders by mimicking caloric restriction; however, its structure–activity relationships and molecular targets are still unknown. We aimed to compare the effects of resveratrol and its analogues on adipocyte metabolism and lipid accumulation in vitro. Methods: Mouse embryonic fibroblasts were differentiated to adipocytes in the absence or presence of resveratrol or its derivatives (oxyresveratrol, monomethylated resveratrol, or trimethylated resveratrol). Intracellular lipid content was assessed by Oil Red O staining. Glucose uptake and its response to insulin were estimated by 2-NBDG, and mitochondrial activity was assayed via resazurin reduction. Involvement of potential molecular pathways was investigated by concurrent treatment with their inhibitors. Results: Although lipid accumulation was significantly reduced by all analogues without altering protein content, oxyresveratrol was the most potent (IC50 = 4.2 μM), while the lowest potency was observed with trimethylated resveratrol (IC50 = 27.4 μM). Increased insulin-stimulated glucose uptake was restored by each analogue with comparable efficiency. The enhanced mitochondrial activity was normalized by resveratrol and its methylated derivatives, while oxyresveratrol had a minor impact on it. Among the examined pathways, inhibition of SIRT1, PGC-1α, and JNK diminished the lipid-reducing effect of the compounds. Autophagy appeared to play a key role in the effect of all compounds but oxyresveratrol. Conclusions: Resveratrol and its analogues can mimic caloric restriction with complex mechanisms, including activation of SIRT1, PGC-1α, and JNK, making them possible drug candidates to treat obesity-related diseases.