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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

3. Ubiquinone (Coenzyme Q10, CoQ10)
Cyberlipid.org
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

4. Metabolic functions
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

6. Mitochondrial respiratory chain component
Ubiquinones perform this function by undergoing reversible reduction/oxidation to cycle between the ,4-quinone (oxidized) and 1,4-dihydroxybenzene (reduced) species.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

7. Antioxidant
CoQ10 functions beyond the nonelectron transport chain as a membrane bound antioxidant that protects and spares α-tocopherol in subcellular membranes.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

8. Antioxidant
Along with α-tocopherol, β-carotene and selenium, CoQ10 has been shown to provide significant protection from lipid peroxidation in animal models.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

10. Biosynthesis
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

11. Coenzyme Q10 is synthesized in most tissues.
Biosynthesis
Coenzyme Q10 is synthesized in most tissues.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

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).
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

13. Biosynthesis Biosynthetic rate may decline with age.
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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

14. Dietary sources
The most important food sources are probably tissues of high cellularity and those rich in mitochrondria such as heart and muscle.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

16. Tissue ubiquinone levels:
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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

17. Clinical trials with humans have indicated benefits of supplemental CoQ10 of several types.
Health effects
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

18. Neurologic conditions
Modest improvements in symptoms were reported from a small, randomized, controlled trial with Parkinson’s disease patients.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

19. A small, open-label trial reported CoQ10 to reduce headache frequency.
Migraine
A small, open-label trial reported CoQ10 to reduce headache frequency.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

20. Congestive heart failure
A meta-analysis of randomized, controlled trials showed CoQ10 supplements to reduce dyspnea, edema and the frequency of hospitalization.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

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

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

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.
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

25. Literature
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc