Safety Evaluation of Black Rice Vinegar (Kurosu) from a Jar on Food-drug Interaction: 30-day Ingestion Study on Expressions of Drug Metabolism Enzymes and Transporters in Rats

Black rice vinegar (kurosu) made from a jar is a traditional vinegar in Japan. Kurosu has been commonly used as a healthcare supplement; however, it is not clear whether kurosu has a treatment effect on the expression of drug metabolism enzymes and transporters, whose expression alterations may induce food-drug interaction. Alteration of the principal drug metabolism enzymes and expression following kurosu and moromi, the residue from black vinegar brewing, for 30-day treatment was evaluated. Water, 0.23% acetic acid, concentrated kurosu (containing 0.23% acetic acid) and moromi was administered to Wister rats. The treatment did not significantly affect the biochemical parameters of serum, alanine aminotransferase, alkaline phosphatase, total protein, creatinine in the serum, and body weight. The treatment also did not affect the expression levels of cytochrome P450 (Cyp) 1a2, Cyp2b1/2, Cyp3a1, glutathione S-transferase, p-glycoprotein, multidrug resistance protein 2, breast cancer resistance protein, organic anion transport polypeptide 2, and organic anion transport 2 and 3 in the liver. In conclusion, the present study suggests that kurosu from a jar does not have toxic effect and does not alter expression levels of principal drug metabolism enzymes and transporters.