Silymarin and its components are inhibitors of beta-glucuronidase

Biol Pharm Bull. 1994 Mar;17(3):443-5. doi: 10.1248/bpb.17.443.


Silymarin, a commercial crude drug used as a hepatoprotective, was found to inhibit 53% of beta-glucuronidase activity at a final concentration of 0.8 mg/ml. Of three compounds A, silybin and C, which were isolated from silymarin, A and silybin potently inhibited the enzyme activity, followed by C. beta-Glucuronidases of intestinal bacteria, HGU-1 and HGU-2, and E. coli HB101 were noncompetitively inhibited by silybin. beta-Glucuronidase of the feces of a healthy human and of a human with colon cancer were also inhibited by silybin, silymarin and saccharic acid 1,4-lactone at 0.03-0.15 mg/ml. Silymarin and silybin protected the increase in enzyme activity in the serum of the rats treated with CCl4.

MeSH terms

  • Animals
  • Bacteria / drug effects
  • Bacteria / enzymology
  • Carbon Tetrachloride Poisoning / enzymology
  • Chromatography, Thin Layer
  • Colonic Neoplasms / enzymology
  • Feces / microbiology
  • Glucuronidase / antagonists & inhibitors*
  • Humans
  • Intestines / microbiology
  • Liver / drug effects
  • Liver / enzymology
  • Male
  • Microsomes, Liver / drug effects
  • Microsomes, Liver / enzymology
  • Rats
  • Rats, Wistar
  • Silymarin / chemistry
  • Silymarin / pharmacokinetics
  • Silymarin / pharmacology*


  • Silymarin
  • Glucuronidase