Investigating the anti-cataract potential of Spirulina platensis: Metabolite screening and molecular docking studies

Diabetes is a chronic metabolic condition that can lead to various complications, including cataracts, a chief cause of visual impairment. There is growing promise in the use of natural compounds as preventive and therapeutic agents for cataracts. Oxidative stress has been implicated as a significant factor in cataract development. Natural compounds with antioxidant properties show potential in combating oxidative stress and preventing the formation of cataracts. Among these compounds, Spirulina platensis has been chosen for investigation in this study due to its well-established antioxidant properties. Additionally, this study aims to explore Spirulina platensis as a potential inhibitor of human aldose reductase (hAR), which is proven to show a fundamental role in cataract development. In the course of the work, Spirulina platensis underwent Soxhlet extraction with methanol, yielding four-column fractions (eluotropic solvent series). Each extract was subjected to HR-LCMS metabolite screening. Molecular docking studies were conducted to identify potential hAR inhibitors, and in vitro, anti-cataract activity was assessed using a goat lens model. The methanol fraction (500 μg/ml) showed the most significant anti-cataract activity, with a lens morphology grade 1 and improvements in superoxide dismutase (SOD) activity (1.565±0.10 U/mg of tissue, p<0.001), catalase (CAT) levels (6.59±0.25 U/mg of tissue, p<0.001), glutathione (GSH) concentrations (21.19±21.19 nmoles/100 mg, p<0.001) and protein content (255.5±5 mg/dl, p<0.001). Molecular docking identified Dubamine (methanol fraction, docking score: -11.0 kcal/mol) as a potential hAR inhibitor with the highest binding affinity. These results demonstrate the molecular pathways underlying Spirulina platensis therapeutic potential against cataracts. Keywords: Spirulina platensis, HR-LCMS, molecular docking, anti-cataract activity, biochemical parameters