Anthocyanin-rich fraction from black rice, Oryza sativa L. var. indica "Luem Pua," bran extract attenuates kidney injury induced by high-fat diet involving oxidative stress and apoptosis in obese rats.

Obesity is acknowledged as being a world health problem and increases the risk of several chronic diseases including chronic kidney disease. High-fat diet consumption and obesity-related renal disease show a close correlation with increased oxidative stress. Black rice bran extract, (BRE) Oryza sativa L. variety "Luem Pua" contains a high anthocyanin content. This study evaluated the effects of an anthocyanin-rich fraction from BRE on renal function and oxidative stress in obese rats. Male Wistar rats were fed a normal diet (ND) or high-fat diet (HF) for 16 weeks. After this, the rats were given either vehicle (HF), BRE 100 (HF100) or BRE 200 mg/kg/day (HF200) orally for 8 weeks. The HF rats had increased body weight, visceral fat weight, plasma glucose, cholesterol and triglycerides. These parameters were normalized following HF100 administration and showed a decreasing trend with HF200. Serum creatinine and renal cortical MDA were increased in the HF group but these effects were attenuated by BRE. Negative kidney injury and histopathology changes were observed following a HF, but treatment with BRE reversed these deleterious effects. These results suggest that BRE could be used as a food supplement to improve metabolic disturbance and prevent kidney dysfunction in cases of obesity.

Effect of wall materials on some physicochemical properties and release characteristics of encapsulated black rice anthocyanin microcapsules.

Anthocyanin-rich extracts derived from the bran of a select Thai black rice cultivar, Leum Pua, were encapsulated by spray drying. In this microencapsulation method, twelve wall materials comprising maltodextrin (M), gum arabic (G), whey protein isolate (W), and their combinations were employed. For comparison, an ionic gelation method was employed using alginate-whey protein isolate (AL-W) as a wall material. Thirteen microcapsules were analysed by scanning electron microscopy, and their encapsulation efficiencies were almost 100%, except for that of the W (83%). M (88%) and its combination with W exhibited the best anthocyanin retention, while pure W contained the highest amount of total phenolic compounds and antioxidant activity. An in vitro digestion study using simulated gastrointestinal fluids revealed the highest released total phenolic content and antioxidant activity of the intestinal fluids when the microcapsule was spray-dried with pure W.