Switching to Black Rice Diets Modulates Low-Density Lipoprotein Oxidation and Lipid Measurements in Rabbits

The effect of white and black rice consumption on lipid profile, hydroperoxides, thiobarbituric reactive substances and oxidized low-density lipoprotein (LDL) induced by hypercholesterolemia was investigated in 24 male rabbits; a purified normal diet (NC, n = 6), a high fat/cholesterol (1.0 g/100 g) diet (PC group, n = 6), a high fat/cholesterol diet with 25 g/100 g white ground rice (PCWR group, n = 6), 25 g/100 g black ground rice (PCBR group, n = 6) for 10 weeks. Blood samples were collected for lipid measurements. Results indicate that serum high-density lipoprotein-cholesterol was higher (P < 0.05) in the PCBR compared with the PC and PCWR groups. Hydroperoxides and thiobarbituric reactive substances were significantly lower (P < 0.05) in the PCBR compared with PCWR and PC groups. Cyanidin-3-glucoside (Cy-3-Glu) and peonidin-3-glucoside have been tested in vitro against copper-mediated low-density lipoprotein. Cy-3-Glu was excelled peonidin-3-glucoside by increasing the lag time of NC from 80 to 500 minutes in the presence of 2.0 mu M of Cy-3-Glu. Hierarchically, black rice rabbits group was given the best results compared with other groups. The results may be indicating to a suggested mechanism (anthocyanins protection; Cy-3-Glu) of the cardioprotective effect of black rice.