Catechol inhibits FADH2-linked respiration in rat liver mitochondrial fraction.
OBJECTIVE
The aim of this work was to investigate the hypothesis that catechol inhibits FADH -linked basal respiration in mitochondria isolated from rat liver homogenates. Moreover, catechol ability to induce peroxidation of biomolecules in liver nuclear fractions was also studied.


METHODS
Rat liver homogenates were incubated with 1mM 1,2-dihydroxybenzene (catechol) at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate. Nuclear fractions were incubated in the presence of 1 mM catechol for 17 hours at room temperature and the peroxidation of biomolecules was investigated by the reaction with thiobarbituric acid, which was determined spectrophotometrically at 535 nm.


RESULTS
Catechol induced a time-dependent partial inhibition of FADH -linked basal mitochondrial respiration, however this substance was unable to induce a direct peroxidation of biomolecules in hepatic nuclear fractions.


CONCLUSIONS
Catechol produced an inhibition of basal respiration associated to FADH2 in isolated liver mitochondria that could lead to cytotoxicity, ROS generation and cell death.
Barreto
George Emílio Sampaio
GE
Laboratory of Dispersed Systems (LASID), Department of Pharmacy, Federal University of Rio Grande do Norte (UFRN), Natal, RN, Brazil.
dos Santos
Gleide Souza
GS
Egito
Eryvaldo Sócrates Tabosa
ES
El-Bachá
Ramon dos Santos
Rdos S
D000818:Animals; D002396:Catechols / Q000633:toxicity*; D002467:Cell Nucleus / Q000187:drug effects; D019069:Cell Respiration / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005182:Flavin-Adenine Dinucleotide / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors; D015227:Lipid Peroxidation / Q000187:drug effects*; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors
D002396:Catechols; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D005182:Flavin-Adenine Dinucleotide; C058805:1,5-dihydro-FAD; C034221:catechol