Treatment of Diabetes Nephropathy in Mice by Germinating Seeds of Euryale ferox through Improving Oxidative Stress

Diabetes can cause severe kidney disease. Euryale ferox seeds (Gordon Euryale) have known antioxidant, hypoglycemic, and renal protection effects. Methanol extracts of Gordon Euryale were produced from ungerminated and germinated seeds. The effect of germination on polyphenol and flavonoid content was investigated by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Three doses of ungerminated seed extract (EKE) and germinated seed extract (GEKE) were administered to diabetic mice by gavage to explore the treatment-dependent improvement of oxidative stress, metabolic disorder, and kidney disease. Seed germination led to a 1.7 times increase in total phenol content in the extract, and the flavonoid content was increased by 1.9 times. Germination greatly increased the contents of 29 polyphenols and 1 terpenoid. At the same dose, GEKE more strongly improved hyperglycemia, abnormal lipid metabolism, and renal tissue lesions (as confirmed by histology) in the diabetic mice than EKE did. In diabetic mice receiving treatment, kidney microalbunminuria (ALB), blood urea nitrogen (BUN), serum creatinine (Scr), malondialdehyde (MDA), and glutathione (GSH) were all decreased, while activity of catalase (CAT), superoxide dismutase (SOD), and serum total antioxidant capacity (T-AOC) were increased. Both EKE and GEKE can improve diabetes and kidney disease by improving hyperglycemia, oxidative stress, and kidney physiological indicators and regulating the Keap1/Nrf2/HO-1 and AMPK/mTOR pathways. However, in both pathways, GEKE is more effective. The purpose of this study was to explore the effects of GEKE and EKE treatment on antioxidant defense and metabolic capacity of diabetic animals. Germination provides a suitable strategy to improve the medicinal value of these natural plant-based products.