Quinone: A Scientific Overview

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A quinone refers to a class of compounds that are oxidized variants of benzene rings. More specifically, they are any structure attached to a benzene ring that has a pair of ketone groups.

These compounds are commonly used in organic chemistry to trigger reactions when combined with other materials to create new substances. They are also present in some dyes, usually in the shades of red. Also, large-scale industrial manufacturers will use quinones to create massive quantities of hydrogen peroxide.

When biologists refer to quinone, they are usually referring to Coenzyme Q - Ubiquinone. However, in the body, there are two different classes of quinones: K vitamins and Ubiquinones.

Vitamin K

Vitamin K is an all-important essential nutrient that your body needs. Vitamin K plays a role in coagulation, cardiovascular health, and bone health.

Vitamin K is a fat-soluble vitamin which means that it is better ingested and absorbed when taken with fatty foods such as fish, eggs, and dairy. Vitamin K is found in two forms in the body: K1 and K2.

Vitamin K1, also known as phylloquinone, can be found primarily in leafy vegetables and is used by the liver to produce coagulation factors, which are important for blood clotting and scab formation.

Vitamin K2 specializes in the movement of calcium out of the blood vessels and into the bones where it belongs. When excess calcium is in the bloodstream, it can become deposited in the heart and arteries in response to plaque. Coronary calcification is one of the main mechanisms behind heart disease and atherosclerosis.

Vitamin K2 is really a bunch of different menaquinones (MKs) with different side chain lengths. Two commonly referred to are MK-4 and MK-7, but there are many more. Research shows that the length of the side chain is what determines the body’s ability to absorb the molecule.

MK-7 and other long-chained menaquinones are easily absorbed into the body and have a relatively small nutritional need in contrast to MK-4, which is not really absorbed into the body and has a relatively high nutritional need.

This has caused some scholars to call for the separation of MK-4 and MK-7 as it relates to dietary recommendations. If you are looking for a vitamin K2 supplement, be sure to look for longer chain menaquinones.

Vitamin K-Rich Foods

Some foods that have been shown to contain high amounts of this easily absorbable vitamin K2 include:

  • Cheese. Specifically, soft and aged cheeses like blue, Swiss Emmental, and Norwegian Jarlsberg have high concentrations of MK-9 and other long-chain menaquinones. The key is in what species of bacteria are used in the cheese-making process.

Fermented dairy products that used different bacteria in the cheese-making process, such as mozzarella and yogurt, were found to have small to no long-chain menaquinones.

  • Natto. Natto is a traditional Japanese fermented soy dish that contains the highest amount of menaquinones of any food, most of which come in the MK-7 form. It weighs in at a whopping 250 mcg per ounce. If you are looking to get your vitamin K2 through your diet, this is the way to go.
  • Supplements. While not necessarily food, per se, they are a great source of dietary vitamin K2. Be sure to get a K2 supplement derived from MK-7 or other long-chain menaquinones.


One of the most important mechanisms in the body is the one that converts the food you eat into usable energy called cellular respiration. The many systems that your body goes through to complete this bigger mechanism are all astounding and unique in their own way.

First, your body intakes the food and breaks it down into Acetyl-CoA. The route that food takes depends on what kind of macromolecule it is -- and whether or not the body needs to be using that type of fuel for food. Sugars are burned first and/or turned into fat to be stored for when the sugar runs out.

Once the body has these Acetyl-CoA molecules, it plugs them into a process called the Krebs Cycle, Citric Acid Cycle, or Tricarboxylic Acid (TCA) Cycle. It has gone by many names throughout the years.

The TCA cycle is the process by which the body maximizes the amount of energy it can get from breaking a single carbon-carbon bond.

From a physics perspective, everything is drawn to each other to different degrees based on each property. However, to work against the natural draw of these properties requires energy. For instance, you need to exert force into the ground to overcome gravity, for a moment, and jump.

Molecules have this principle applied to them as well. When two molecules bond together, it takes energy to do so, but they also get stuck together due to other forces.

Now the two objects have potential energy that is ready to be utilized. When that bond is broken, the energy is released. The more energy it takes to make the bond, the more energy is released when that bond is broken.

The problem is that carbon-carbon bonds have too much energy.

Too Much Energy 

Breaking a carbon-carbon bond for reactions in the body would be quite wasteful. Not to mention, how much we would have to eat to stay alive! So, the body breaks the bond slowly through the many reactions called the TCA cycle.

Once the body gets Acetyl-CoA, then it puts it through the TCA cycle causing the B3 and B2 vitamin-based electron carrier molecules NAD+ and FAD to pick up the extra electrons. They move the electrons to the electron transport chain (ETC), which is a series of enzymes that use the electrons to create a charge differential across the inner membrane of the mitochondria. This charge differential facilitates the production of ATP, which is the molecule used for energy throughout the body.

ETC Complex II, Succinate Dehydrogenase, takes the energized electrons from FADH2 using iron and passes it along to Coenzyme Q, ubiquinone, changing it to ubiquinol. A similar reaction happens at ETC Complex I to take energized electrons from NADH.

The ubiquinol then moves along inside the inner mitochondrial membrane to transfer the energized electrons to ETC Complex III, which packages them up in cytochrome C.

Cytochrome C brings the energized electrons to ETC Complex IV via the intermembrane space, which attracts the protons. These protons then flow across the membrane, establishing a concentration gradient that ATP synthase uses to make ATP.

Health Benefits of Coenzyme Q

There are plenty of health benefits for both classes of quinones: vitamin K and coenzyme Q. We briefly touched on some of the important factors of vitamin K, so let’s focus on coenzyme Q.

Reduced Risk of Heart Disease

Many studies have pointed out that low CoQ10, particularly in cardiac tissue, is present in people who experience heart attacks. In fact, the severity of the heart attack has been shown to increase as the concentration of CoQ10 decreases. All in all, the importance of CoQ10 for heart health cannot be understated.

Increased Energy Levels

Coenzyme Q can have several different side chain lengths in different organisms, but in humans, the side chain is ten carbon molecules long. This is why coenzyme Q is usually referred to as CoQ10. Supplementation with CoQ10 has been shown to have a plethora of health benefits, including improved energy levels.

Since CoQ10 is deeply involved with the energy-producing mechanism, it should be no surprise that having more can help boost your energy production throughout the day.

Battles Fatigue and Depression

CoQ10 is a powerful antioxidant; In the electron transport chain, it is specifically used to reduce iron molecules time and time again in order to transport those electrons to ETC Complex III. These antioxidant powers can be leveraged in other places across the body as well.

For instance, one study found that patients who received 500 mg of CoQ0 daily experienced improvements in both fatigue and depression, as compared to the placebo group. This is likely due to the fact that depression has high oxidant effects on the body and lowers the level of CoQ10, as determined by another study.

Reduce Risk of Fibromyalgia

In a study published in Antioxidants and Redox Signaling Journal, patients taking 300 mg of CoQ10 daily for 40 days experienced a major reduction in pain, fatigue, morning tiredness, and joint tenderness.

Aid in Infertility

In a study published in the Journal of Urology, men with unexplained infertility were given 200 mg of CoQ10 for 26 weeks versus placebo. The CoQ10 group experienced improvements in sperm motility, sperm count, and the size and shape of the sperm, which suggested that CoQ10 may be helpful for men with unexplained infertility.

Supports Treatment for Migraines

One study compared a placebo group to a group taking 100 mg of CoQ10 three times daily. What they found was a 33% reduction of attack frequency in those who were taking the CoQ10 supplement.

In Summary

Quinones are a class of compounds that have a diketone group attached to a benzene ring. Typically clinicians use this term to refer to coenzyme Q, but its chemical definition also encompasses the essential nutrient vitamin K.

Vitamin K and coenzyme Q are integral to heart health, the former through calcium regulation and the latter through oxidation management and energy production.

These nutrients also have extra benefits for other health areas as well including bone health, energy levels, fatigue and depression, fibromyalgia, infertility, and migraines.

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Healthy Directions Staff Editor