Genotoxicity studies of quercetin and shikimate in vivo in the bone marrow of mice and gastric mucosal cells of rats.
Bracken fern (Pteridium aquilinum) causes acute and chronic toxicity in animals and is associated with a high incidence of stomach and esophageal tumors in humans in countries where it is consumed as food, yet the toxic constituent(s) has not been unequivocally identified. None of the toxic constituents so far isolated from bracken have individually reproduced all the disease syndromes typical of the plant. The carcinogenicity of the plant has at one time or another been attributed to quercetin, shikimate or ptaquiloside. Studies to determine whether or not the genotoxicity of quercetin, shikimate (and its metabolite cyclohexane-carboxylate) could be enhanced in combined application were conducted in vivo using the micronucleus test in mice and the unscheduled DNA synthesis in rat gastric mucosal cells. None of these compounds were genotoxic; simultaneous administration of the compounds did not influence their in vivo genotoxicity. Plasma concentrations of quercetin after p.o. and i.p. administration at 200 mg/kg were below 0.1 microgram/ml, suggesting that the negative in vivo results may have been due to limited bioavailability of the compound.
Ngomuo
A J
AJ
Department of Veterinary Physiology, Sokoine University of Agriculture, Morogoro, Tanzania.
Jones
R S
RS
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects*; D001854:Bone Marrow Cells; D002273:Carcinogens / Q000008:administration & dosage / Q000633:toxicity*; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects; D004357:Drug Synergism; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005753:Gastric Mucosa / Q000166:cytology / Q000187:drug effects*; D008297:Male; D051379:Mice; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects / Q000235:genetics; D015162:Micronucleus Tests; D010939:Plant Poisoning / Q000209:etiology / Q000662:veterinary; D011794:Quercetin / Q000008:administration & dosage / Q000097:blood / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012765:Shikimic Acid / Q000008:administration & dosage / Q000378:metabolism / Q000633:toxicity*; D013936:Thymidine / Q000378:metabolism
D002273:Carcinogens; D003509:Cyclohexanecarboxylic Acids; D012765:Shikimic Acid; D004247:DNA; D011794:Quercetin; D013936:Thymidine