Quasi vitamins, ubiquinones (coenzyme Q10)

1. Quasi-vitamins:
Ubiquinones
Domina Petric, MD

2. Chemical nature
The ubiquinones are a
group of tetra-substituted
1,4-benzoquinone
derivatives with
isoprenoid side chains of
variable length.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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3. Ubiquinone
(Coenzyme Q10, CoQ10)
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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Cyberlipid.org

4. METABOLIC FUNCTIONS
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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5. Mitochondrial respiratory
chain component
• The ubiquinones function as
electron acceptors for complexes I
and II of mitochondrial electron
transport chains.
• They pass electrons from
flavoproteins (NADH or succinic
dehydrogenases) to the
cytochromes via cytochrome b5.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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6. Mitochondrial respiratory
chain component
Ubiquinones perform this
function by undergoing
reversible reduction/oxidation
to cycle between the
1,4-quinone (oxidized) and
1,4-dihydroxybenzene
(reduced) species.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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7. Antioxidant
CoQ10 functions beyond
the nonelectron transport
chain as a membrane
bound antioxidant that
protects and spares
α-tocopherol in
subcellular membranes.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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8. Antioxidant
Along with
α-tocopherol,
β-carotene and
selenium, CoQ10
has been shown
to provide
significant
protection from
lipid peroxidation
in animal models.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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9. Antioxidant
Administration of CoQ10 has been
found to protect against
myocardial damage mediated by
free-radical mechanisms
(ischemia, drug toxicities) in
animal models.
It has been proposed that CoQ10
plays a major role in the
determination of membrane
potentials of subcellular
membrane systems.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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10. BIOSYNTHESIS
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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11. Biosynthesis
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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12. Biosynthesis
• The biosynthetic process derives
the isoprenyl side chain from
mevalonate, the ring system from
tyrosine, the hydroxyl groups
from molecular oxygen and the
methyl groups from
S-adenosylmethionine to produce
a 50-carbon polyisoprene chain
(containing 10 isoprene units).
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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13. Biosynthesis
• Because endogenous tissue
biosynthesis appears sufficient to
support membrane saturation
levels, supplementation increases
tissue levels above normal in only
liver and spleen.
• Biosynthetic rate may decline
with age.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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14. Dietary sources
The most
important food
sources are
probably tissues
of high cellularity
and those rich in
mitochrondria
such as heart and
muscle.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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15. Tissue distribution
• Coenzyme Q10 is distributed in all
membranes in the cell.
• Relatively great concentrations of
CoQ10 are found in the liver, heart,
spleen, kidney, pancreas and
adrenals.
• The total CoQ10 pool size in the
human adult is estimated
to be 0.5–1.5 g.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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16. Tissue distribution
Tissue ubiquinone levels:
• Increase under the influence of
oxidative stress, cold
acclimation and thyroid
hormone treatment.
• Decrease with
cardiomyopathy, other muscle
diseases and aging.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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17. HEALTH EFFECTS
Clinical trials with humans have
indicated benefits of supplemental
CoQ10 of several types.
26.4.2018. Combs GF. The Vitamins. Fundamental Aspects
in Nutrition and Health. Elsevier Inc. 2008.
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18. Neurologic
conditions
Modest improvements in
symptoms were reported
from a small, randomized,
controlled trial with
Parkinson’s disease
patients.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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19. Migraine
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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20. Congestive heart
failure
A meta-analysis of
randomized,
controlled trials
showed CoQ10
supplements to
reduce dyspnea,
edema and the
frequency of
hospitalization.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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21. Hypertension
• A systematic review of eight
randomized, controlled trials
suggested that CoQ10
supplementation to decrease
systolic pressure by an
average of 16 mmHg, and
diastolic pressure by an
average of 10 mmHg.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
21

22. Atherosclerosis
A randomized, controlled
trial found CoQ10
supplementation after
myocardial infarction to
reduce subsequent
myocardial events and
cardiac deaths.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
22

23. Endothelial
dysfunction
A randomized, controlled
trial found CoQ10
supplementation to
improve endothelial
function of peripheral
arteries of dyslipidemic
patients with type II
diabetes.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
23

24. Tolerance to cancer
chemotherapy
• A systematic review of six
randomized, controlled
trials suggested that CoQ10
supplementation provided
some protection against
cardiac or hepatic toxicity.
26.4.2018. Combs GF. The Vitamins.
Fundamental Aspects in Nutrition
and Health. Elsevier Inc. 2008.
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25. Literature
• Combs GF. The Vitamins. Fundamental Aspects in
Nutrition and Health. Elsevier Inc. 2008.
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