Protection against aflatoxin-B1-induced liver mutagenesis by Scutellaria baicalensis.
We have measured the inhibition of the mutagenicity of the mycotoxin aflatoxin-B(1) in the liver of the rat by plant material of Scutellaria baicalensis, or Huang-qin. The addition of one percent dried Huang-qin to the feed of the animals reduced the mutant frequency of a subsequent administration of aflatoxin-B1 by approximately 60 and 77%, respectively, for two different batches of the plant material. The addition of Huang-qin also increased the expression of the gene for glutathione S-transferase A5 subunit by 2.5-3.0-fold, and decreased expression of P450 cytochrome 3A2 by 1.8-2.0-fold. The greater increase of the expression of the GST gene may result in the protection shown by Huang-qin. The sensitivity of the hepatic mitochondria to swelling, a measure of the mitochondrial permeability transition, is increased significantly in animals that are on a diet containing Huang-qin. This may lead to increased sensitivity to apoptosis on treatment with toxic compounds. The two batches of Huang-qin material show differences in both chemical composition and preventive potential. This study demonstrates how a combination of generating and analysis of plant varieties together with a mammalian assay for efficacy may improve the search for better plant-based prevention of cancer initiation.
de Boer
Johan G
JG
Centre for Biomedical Research, University of Victoria, P.O. Box 3020 STN CSC, Victoria, BC, Canada V8W 3N5. jdboer@uvic.ca
Quiney
Brendan
B
Walter
Patrick B
PB
Thomas
Cynthia
C
Hodgson
Kimberley
K
Murch
Susan J
SJ
Saxena
Praveen K
PK
D016604:Aflatoxin B1 / Q000633:toxicity*; D000818:Animals; D030801:Animals, Genetically Modified; D016587:Antimutagenic Agents / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects; D009153:Mutagens / Q000633:toxicity*; D011897:Random Allocation; D051381:Rats; D031364:Scutellaria baicalensis / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
D016587:Antimutagenic Agents; D009153:Mutagens; D003577:Cytochrome P-450 Enzyme System; D016604:Aflatoxin B1; D005982:Glutathione Transferase