Macular pigments produced from microalga Chlorella sp. and applied to alleviate the pathogenic process in diabetic mice

Macular pigments (MP), which consist of lutein and zeaxanthin, have antioxidant capabilities and are widely used in eye healthcare. However, few studies have focused on the protective mechanisms of MP against diabetes mellitus. In addition, the advantages of MP produced by microalgae include non-competition with grains for land, year-round harvesting, and rapid growth. Therefore, this study aims to investigate the MP produced and extracted from the microalga Chlorella sp. AT1 and assess its impact on mitigating retinopathy and atherosclerotic damage in diabetic apolipoprotein E-deficient mice (ApoE^−/−) subjected to high-fat diet and streptozotocin treatment. The results showed that the major components of MP were lutein and zeaxanthin in a 5:1 ratio. MP supplementation significantly reduced glucose tolerance and insulin resistance by 25 and 41 %, respectively, in comparison to the diabetic group. MP supplementation resulted in the moderation of various inflammatory cytokines and lowered the serum levels of disease markers in comparison to the control group. In addition, the expression levels of cellular antioxidant enzymes were significantly elevated, aligning with a reduction in lipid peroxidation after MP supplementation, in comparison to the diabetic group. Pathological changes in the outer nuclear layer and aortic plaques in diabetic ApoE^−/− mice were significantly alleviated by MP supplementation. In summary, microalgal MP alleviated the symptoms of type 2 diabetes mellitus in the diabetic ApoE^−/− mice. Consequently, MP holds the potential to serve as a beneficial ingredient in healthy food, contributing to biological efficacy by scavenging free radicals and stabilizing blood glucose levels.