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HERO ID
628986
Reference Type
Journal Article
Title
Lichen acids as uncouplers of oxidative phosphorylation of mouse-liver mitochondria
Author(s)
Abo-Khatwa, AN; Al-Robai, AA; Al-Jawhari, DA
Year
1996
Is Peer Reviewed?
1
Journal
Natural Toxins
ISSN:
1056-9014
Volume
4
Issue
2
Page Numbers
96-102
Language
English
PMID
8726330
DOI
10.1002/19960402NT7
Abstract
Three lichen acids-namely, (+)usnic acid, vulpinic acid, and atranorin- were isolated from three lichen species (Usnea articulata, Letharia vulpina, and Parmelia tinctorum, respectively). The effects of these lichen products on mice-liver mitochondrial oxidative functions in various respiratory states and on oxidative phosphorylation were studied polarographically in vitro. The lichen acids exhibited characteristics of the 2,4-dinitrophenol (DNP), a classical uncoupler of oxidative phosphorylation. Thus, they released respiratory control and oligomycin inhibited respiration, hindered ATP synthesis, and enhanced Mg(+2)-ATPase activity. (+)Usnic acid at a concentration of 0.75 microM inhibited ADP/O ratio by 50%, caused maximal stimulation of both state-4 respiration (100%) and ATPase activity (300%). Atranorin was the only lichen acid with no significant effect on ATPase. The uncoupling effect was dose-dependent in all cases. The minimal concentrations required to cause complete uncoupling of oxidative phosphorylation were as follows: (+)usnic acid (1 microM), vulpinic acid, atranorin (5 microM) and DNP (50 microM). It was postulated that the three lichen acids induce uncoupling by acting on the inner mitochondrial membrane through their lipophilic properties and protonophoric activities.
Keywords
2; 4-Dinitrophenol; toxicity; Adenosine Triphosphate; biosynthesis; Animal; Anti-Infective Agents; Benzofurans; Ca(2+) Mg(2+)-ATPase; metabolism; Dose-Response Relationship; drug; Furans; Hydroxybenzoic Acids; In Vitro; Male; Mice; Mitochondria; Liver; drug effects; Oligomycins; Oxidative Phosphorylation; Oxygen Consumption; Phenylacetates; Polarography; Uncoupling Agents
Tags
•
ISA-CO (2010 Final Project Page)
Health Effects
•
ISA-NOx (2016)
Considered
Health Effects
•
ISA-SOx
Health Effects
•
PM Provisional Assessment (2012 Project Page)
Epidemiological Studies
Non-U.S.
Cardio (hospital/emergency)
Respiratory (hospital/emergency)
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