Extraction of raspberry ketone from red raspberry and its intervention in the non-alcoholic fatty liver disease

Abstract Nonalcoholic fatty liver disease (NAFLD) is characterized by diffused hepatocyte bullous fat in the liver, which is not caused by alcohol or drugs like amiodarone and tamoxifen. Presently, no drug is approved for NAFLD treatment. Therefore, it’s important to extract effective components from natural plants to alleviate NAFLD. In this study, we extracted and purified raspberry ketone, a natural phenolic compound from red raspberry ( Rubus ideaus L.) by an ultrasonic-assisted ethanol extraction method. The structure of red raspberry ketone (RRK) was determined using Fourier-transform infrared spectroscopy and the purity of RRK was found as 80.06 ± 1.19%. After 28 days of intragastric administration of RRK, the bodyweight of NAFLD model rats decreased significantly (p < 0.05). Besides, the levels of low-density lipoprotein cholesterol, total cholesterol, and total triglyceride (TG) decreased and the content of high-density lipoprotein cholesterol in serum increased drastically. Moreover, the level of liver damage indicators (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) and the levels of glucose, insulin, free-fatty acid, tumor necrotic factor-α in the liver decreased distinctly. The levels of TG and malondialdehyde in the liver decreased, whereas the levels of superoxide dismutase, total glutathione, and glutathione peroxidase drastically increased. We also found that RRK reduced the uneven size of liver cells and blurred boundaries of hepatic lobules, and alleviated hepatic steatosis and inflammation caused by NAFLD. We inferred that RRK could relieve NAFLD progression by regulating glucose and lipid metabolism and alleviating oxidative stress in vivo. This study sheds new light on the use of RRK as a functional food for NAFLD prevention.