Preventive effect of siphonaxanthin, a carotenoid from green algae, against diabetic nephropathy and lipid metabolism insufficiency in skeletal muscle.

Diabetic nephropathy is a complication of diabetes mellitus characterized by the gradual progression of renal insufficiency, resulting in renal failure. Approximately 15 % or more of patients with type 2 diabetes mellitus have diabetic nephropathy. Siphonaxanthin is a green algal carotenoid noted for its strong biological activities, including anti-obesity effects. In this study, we aimed to evaluate the preventive effects of siphonaxanthin on diabetic nephropathy using db/db mice as a type 2 diabetes mellitus and diabetic nephropathy model. Ingestion of AIN-93G containing 0.004 % w/w siphonaxanthin did not improve plasma creatinine and urine albumin levels but significantly mitigated renal morphological changes in diabetic mice. Moreover, siphonaxanthin restored the decreased mRNA expression of fatty acid β-oxidation-related proteins in the skeletal muscle. These results indicate that siphonaxanthin can potentially ameliorate type 2 diabetes mellitus-induced kidney damage and lipid metabolism insufficiency in skeletal muscle. This study provides a possible daily nutraceutical solution for treating diabetic nephropathy and lipid metabolic abnormalities.