Background: Neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis, represent a major global health burden and share convergent pathogenic mechanisms, such as mitochondrial dysfunction, oxidative stress, neuroinflammation, calcium imbalance, and neuronal loss. Despite advances in symptomatic management, effective disease-modifying therapies remain limited. Objectives: This review aims to critically synthesize mechanistic, preclinical, and clinical evidence on α-lipoic acid and biotin as candidate neuroprotective agents in neurodegenerative diseases, with emphasis on shared signaling pathways, therapeutic potential, generally favorable safety profiles, and translational limitations. Methods: A narrative and integrative review was conducted, encompassing mechanistic studies, preclinical experimental models, and clinical trials and observational studies evaluating ALA and biotin in neurodegenerative diseases. The evidence was qualitatively analyzed with attention to biological plausibility, consistency across models, and clinical relevance. Results: ALA and biotin modulate key cellular pathways implicated in neurodegeneration, including mitochondrial metabolism, redox homeostasis, inflammatory signaling, and neurovascular function. Preclinical studies consistently report beneficial effects on mitochondrial efficiency, oxidative stress, and neuroinflammatory markers. In contrast, clinical evidence remains heterogeneous, with more extensive evaluation of biotin in progressive multiple sclerosis and more limited or exploratory findings for ALA across neurodegenerative disorders. Conclusions: ALA and biotin exhibit mechanistic convergence across pathways relevant to neurodegeneration and generally favorable safety profiles. Although current evidence supports their biological plausibility as adjunctive or exploratory therapeutic strategies, clinical outcomes remain inconsistent and appear to be influenced by dosing regimens, disease stage at intervention, and endpoint selection. Well-designed clinical studies are required to define their efficacy, optimal dosing, and disease-specific applicability.

Numerous studies indicate that intrauterine growth restriction (IUGR) can predispose individuals to metabolic syndrome (MetS) in adulthood. Several reports have demonstrated that pharmacological concentrations of biotin have therapeutic effects on MetS. The present study investigated the beneficial effects of prenatal biotin supplementation in a rat model of intrauterine caloric restriction to prevent cardiometabolic risk in adult female offspring fed fructose after weaning. Female rats were exposed to a control (C) diet or global caloric restriction (20%) (GCR), with biotin (GCRB) supplementation (2 mg/kg) during pregnancy. Female offspring were exposed to 20% fructose (F) in drinking water for 16 weeks after weaning (C, C/F, GCR/F, and GCRB/F). The study assessed various metabolic parameters including Lee’s index, body weight, feed conversion ratio, caloric intake, glucose tolerance, insulin resistance, lipid profile, hepatic triglycerides, blood pressure, and arterial vasoconstriction. Results showed that GCR and GCRB dams had reduced weights compared to C dams. Offspring of GCRB/F and GCR/F dams had lower body weight and Lee’s index than C/F offspring. Maternal biotin supplementation in the GCRB/F group significantly mitigated the adverse effects of fructose intake, including hypertriglyceridemia, hypercholesterolemia, hepatic steatosis, glucose and insulin resistance, hypertension, and arterial hyperresponsiveness. This study concludes that prenatal biotin supplementation can protect against cardiometabolic risk in adult female offspring exposed to postnatal fructose, highlighting its potential therapeutic benefits.

Background/Objectives: Pain is a growing public health concern worldwide, and the use of combinations of drugs can improve their analgesic effects while minimizing their adverse effects. Drugs such as metformin (antidiabetic) and melatonin (sleep regulator) have analgesic potential in combination. In this study, we evaluated the pharmacological interaction between metformin and melatonin when orally administered in a rat model, using the formalin test. Methods: Female Wistar rats (220–350 g) were injected with 50 µL of 1% formalin in the dorsal surface of the right hind paw. Formalin produces pain-related flinching behavior, and antinociception was evaluated as the reduction in this response. The percentage of the antinociceptive effect was determined after the oral administration of metformin (30–1000 mg/kg), melatonin (10–150 mg/kg), and their combination (MMC). To establish the nature of the interaction, isobolographic analysis was performed in a fixed-dose ratio (0.5:0.5), based on the effective dose 50 (ED₅₀) values for each drug: metformin (947.46 ± 242.60 mg/kg) and melatonin (126.86 ± 37.98 mg/kg). To evaluate the mechanism of action, the receptor antagonist for metformin compound C (dorsomorphin) for AMPK inhibition, MT1 and MT2 melatonin receptor antagonists (4-P-PDOT, luzindole), and an opioid antagonist (naloxone) were employed. The rotarod test was used to evaluate the safety profile of the combination. Results: The metformin–melatonin combination significantly reduced the number of flinches in the second phase of the formalin test. The theoretical ED₅₀ for the combination (ED₅₀ T) was 537.15 ± 122.76 mg/kg. Experimentally, the ED₅₀ (ED₅₀ E) was significantly lower (360.83 ± 23.36 mg/kg), indicating a synergistic interaction for the combination involving opioidergic pathways, MT2 receptors, and AMPK activation. Conclusions: Oral metformin–melatonin coadministration could provide a therapeutic alternative for inflammatory pain.

Combination therapy approaches to manage acute and chronic pain are commonly used. To characterize the interaction between ketorolac and topiramate in the formalin test, female Wistar rats (200-300 g) were submitted to 1% formalin test. Antinociceptive effect was determined by the administration of ketorolac (3, 10, 30 and 100 mg/kg), topiramate (25, 50, 100 and 200 mg/kg) and their combination by oral route; or ketorolac (25, 50, 100 and 200 µg/paw), topiramate (10, 30, 100 and 300 µg/paw) and their combination by local peripheral route. Isobolographic analysis was used in a fixed dose combination (0.5:0.5) to analyze the nature of the interaction of the combination based on the ED50 of ketorolac (62.8±21.9 mg/kg) and topiramate (24.3±8.5 mg/kg) by oral administration; or the ED30 of ketorolac (67.0±7.97 µg/paw) and topiramate (391.3±51.7 µg/paw) by local peripheral route. Combination of these two drugs significantly reduced the number of flinches in second phase of the test. Theoretical ED50 of the oral combination (ED50T) was 43.5±11.7 mg/kg. Experimentally, the ED50 of the combination (ED50E) had a significantly lower value: 16.7±4.0 mg/kg; indicating the presence of supra additive effects (interaction index was 0.38). For local peripheral route, ED30T was 229.21±64.99 µg/kg. Experimentally, the ED30E had a significantly lower value: 62.00±15.72 µg/paw; indicating synergistic effects (interaction index was 0.27). Results show that oral and local peripheral administration of the combination can interact synergistically to reduce inflammatory pain in the rat formalin test.