Polysaccharides Extraction from Opuntia milpa alta and Their Protective Effect on Alcohol-Induced Neuro 2a Cell Damage via Ferroptosis

Alcohol enters the brain through the blood–brain barrier and causes neuronal damage in various ways, additionally long-term and heavy drinking also leads to both structural and functional changes in the central nervous system. Currently, there is a lack of specific therapeutic approaches for alcohol-induced nerve injury. Opuntia milpa alta polysaccharides (MAPs) have various physiological activities such as antioxidant, anti-inflammatory, and neuroprotective effects, but it is not clear how they protect against alcohol-induced nerve injury. In this study, firstly, we structurally characterized homemade MAPs and analyzed the relevance of MAPs in protecting against alcoholic neuronal cell injury and ferroptosis. The results showed that MAPs consisted of nine different monosaccharides and uronic acids. High performance gel permeation chromatography analysis showed that MAPs were homogeneous heteropolysaccharides with an average molecular weight of 8.79 × 106 Da. Fourier infrared spectroscopy showed that they had sulfated pyranopolysaccharides with uronic acids and both α-glycosidic and β-glycosidic bonds were present. Specific signals of these sugars were observed in 1H and 13C NMR spectra. Favorable thermal stability was manifested up to 256 °C. The MAPs had a three-stranded helical structure and a low overall crystallinity. Iron staining showed that alcohol caused significant brown deposition in cells. MAPs significantly ameliorated alcohol-induced cellular damage, reduced iron deposition, and orchestrated the expression of proteins associated with ferroptosis. These results suggest that MAPs protect against alcohol-induced neurological damage, possibly by impeding the onset of cellular ferroptosis.