title: Antihyperglycemic Effect of Quercetin in Ovariectomized Rats Treated with Tamoxifen.
abstract: Tamoxifen is effective in breast cancer therapy in postmenopausal women; however, it causes adverse effects that alter the glycolytic pathway and induce hyperglycemia. Quercetin, a flavonoid with antioxidant potential, inhibits butyrylcholinesterase (BuChE), which is positively associated with hyperglycemia. Therefore, this study investigated the effect of quercetin on tamoxifen-induced hyperglycemia, using BuChE activity as a bioindicator in adult ovariectomized Wistar rats. The ovariectomized rats were treated orally for 14 days with different concentrations of quercetin (2.5, 7.5, 22.5, and 67.5 mg.kg-1b.w.) and tamoxifen (5 mg.kg-1b.w.). Subsequently, they were euthanized; blood and tissue samples were collected. The following biochemical parameters were analyzed: plasma glucose levels and BuChE activity in the plasma, liver, intestine, and adipose tissue. The most effective dose of quercetin in reducing hyperglycemia was 22.5 mg.kg-1b.w. (Que/TAM 4.5/1, P < .00000), although the doses of 2.5 (Que/TAM 0.5/1, P < .05) and 7.5 mg.kg-1b.w. (Que/TAM 1.5/1, P < .05) were also effective. The BuChE activity decreased in the intestine at all tested doses of quercetin coadministered with tamoxifen (P < .01); however, in adipose tissue, there was a biphasic activity with a decrease (P < .05) and increase (P < .05) in activity at doses of 7.5 and 22.5 mg.kg-1b.w. of quercetin, respectively. However, the correlation between BuChE and glucose levels was not significant (P > .05). In summary, the findings of the present study suggest that quercetin when associated with tamoxifen decreases in plasma glucose levels. Furthermore, in these cases, BuChE should not be used as an indicator of hyperglycemia.
authors.affiliation: 1 Laboratory of Cellular Toxicity, State University of West Paraná , Paraná, Brazil .
authors.forename: Fernanda Coleraus
authors.initials: FC
authors.lastname: Silva
authors.affiliation: 1 Laboratory of Cellular Toxicity, State University of West Paraná , Paraná, Brazil .
authors.forename: Isabella Calvo
authors.initials: IC
authors.lastname: Bramatti
authors.affiliation: 1 Laboratory of Cellular Toxicity, State University of West Paraná , Paraná, Brazil .
authors.forename: Adrieli Gorlin
authors.initials: AG
authors.lastname: Toledo
authors.affiliation: 2 Central Vivarium, State University of West Paraná , Paraná, Brazil .
authors.forename: Fernando Marques
authors.initials: FM
authors.lastname: Salles
authors.affiliation: 1 Laboratory of Cellular Toxicity, State University of West Paraná , Paraná, Brazil .|3 Assistance Center in Toxicology, West Paraná University Hospital , Paraná, Brazil .
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Itinose
authors.affiliation: 1 Laboratory of Cellular Toxicity, State University of West Paraná , Paraná, Brazil .|3 Assistance Center in Toxicology, West Paraná University Hospital , Paraná, Brazil .
authors.forename: Carla Brugin
authors.initials: CB
authors.lastname: Marek
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage; D002091:Butyrylcholinesterase / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D010052:Ovariectomy; D011794:Quercetin / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D013629:Tamoxifen / Q000009:adverse effects*
chemical_list: D000975:Antioxidants; D007004:Hypoglycemic Agents; D013629:Tamoxifen; D011794:Quercetin; D002091:Butyrylcholinesterase; D005947:Glucose
keywords: SERM; butyrylcholinesterase; diabetes; flavonoids