Extract of vinegar "Kurosu" from unpolished rice inhibits the proliferation of human cancer cells

J Exp Clin Cancer Res. 2004 Mar;23(1):69-75.


The effects of the ethyl acetate extract of "Kurosu" (EK), Japanese traditional vinegar from unpolished rice, on the proliferation of a variety of human cancer cell lines were investigated by using the alamar blue assay. Cancer cell lines included colon adenocarcinoma (Caco-2), lung carcinoma (A549), breast adenocarcinoma (MCF-7), bladder carcinoma (5637), and prostate carcinoma (LNCaP) cells. EK inhibited the proliferation of all tested cell lines in a dose-dependent manner, with inhibition mostly pronounced in Caco-2 cells (up to 62% inhibition at a dose level of 0.025%). Flow cytometry of EK-treated Caco-2 cells showed a decrease in cell number in the G2/M phase and an increase in the sub-G1 phase (apoptotic). In addition, DNA fragmentation was detected in Caco-2 cells cultured with EK by immunostaining. RT-PCR analysis revealed p21 mRNA expression was induced in EK-treated Caco-2 cells. Moreover, PARP cleavage was promoted in EK-treated Caco-2 cells. These results suggest that EK causes G0/G1 arrest through p21 induction and, thus, is a potential apoptosis inducer in Caco-2 cells.

MeSH terms

  • Acetic Acid / chemistry*
  • Antineoplastic Agents / pharmacology*
  • Apoptosis
  • Blotting, Western
  • Caco-2 Cells
  • Cell Division
  • Cell Line, Tumor
  • DNA / metabolism
  • DNA Fragmentation
  • Dose-Response Relationship, Drug
  • Flow Cytometry
  • Humans
  • Immunohistochemistry
  • Oryza
  • Oxazines / pharmacology
  • Plant Extracts
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Time Factors
  • Xanthenes / pharmacology
  • rho GTP-Binding Proteins / metabolism


  • Antineoplastic Agents
  • Oxazines
  • Plant Extracts
  • RNA, Messenger
  • Xanthenes
  • resazurin
  • DNA
  • rho GTP-Binding Proteins
  • Acetic Acid