HUMAN BIOAVAILABILITY OF TWO COENZYME Q-10 PREPARATIONS AND THEIR IMPACT ON GLUTATHIONE LEVEL IN HUMAN PLASMA

Comparison of pharmaceutical powder and Bio-Foods' formula

Najla Guthrie and Elzbieta M. Kurowska
KGK Synergize Inc., London, ON, Canada

INTRODUCTION

Coenzyme Q-10 (Co Q-10) is indispensable for ATP production in human metabolism. It is also an important antioxidant in human oxidation defense systems. Although it is synthesized in the human body, research found that oral supplementation of Co Q-10 could increase plasma levels, promote heart health and protect humans from oxidation stress.

Co Q-10 is a lipophilic molecule, which means it is easily dissolved in fat, but not in water. This physical property of Co Q-10 is part of the reason for its low absorption in humans and animals, which is reported to be less than 10%. In the Co Q-10 molecule, a 10 unit polyisoprenoid chain is attached to its molecular head. The long lipophilic tails "hate" water very much; therefore in water solution, Co Q-10 tends to clump together rather than disperse evenly as single molecules. This tendency of aggregation increases its difficulty of absorption. Lipid formulation of Co Q-10 in supplementation, which may help it to disperse, was reported to increase absorption compared with the straight powder form.

The current market has many Coenzyme Q-10 products. Some of them try to disperse Co Q-10 into water-soluble systems by physical or mechanical forces. Bio-Foods' process is fermentation, nature's choice to assimilate Co Q-10 into biological membrane systems and to facilitate its dispersion and absorption.

One might ask questions like "What is fermentation" and "What is going on during fermentation". Fermentation is a living process of microorganisms. It makes a big difference when choosing different microorganisms for fermentation. Some microorganisms are so dangerous that they could be used as biological weapons. Some microorganisms are so friendly to human beings that they have been used in human foods for thousands of years, such as the nutritious baker's yeast, Saccharomyces cerevisiae, which is the microorganism in Bio-Foods' fermentation process.

To support its own life during the fermentation, S. cerevisiae must harvest fuel molecules from its foods, in Bio-Foods' case, the nutritious soy containing fermentation media. It utilizes many enzymes to break down big molecules like carbohydrates and proteins to small units to be used as energy fuel and structural components. It also needs to obtain raw materials from its environment to synthesize many indispensable vitamins. To do so, S. cerevisiae has many transportation enzymes including a unique enzyme super family, the ABC protein complex, which "can transport almost any biological substance, regardless of its physical properties" (Winkle, L. J. V. et al. Biomembrane Transport. Academic Press. 1999). A bonus consequence of S. cerevisiae's nutrition producing fermentation process is that many nutrients in the fermentation media are collected by the yeast and associated with different parts of the yeast depending on the nature of the nutrients. Many lipophilic nutrients such as vitamin E and Coenzyme Q-10 are likely to be associated with membrane systems due to their physical properties.

Besides the dispersion and redistribution of Co Q-10 during the yeast fermentation process, S. cerevisiae has a Co Q producing system to support the synthesis of Coenzyme Q.

OBJECTIVES

To determine whether the two Co Q-10 preparations, Bio-Foods fermentation product (BF) and pharmaceutical power (PP) are bioequivalent by comparing their oral bioavailabilities and their impact on glutathione activity in human plasma.

STUDY METHODS

Two different Co Q 10 capsules were used in the study. PP had a purity of 98.7% Co Q-10 and BF had a purity 7.61% Co Q-10 (as determined by HPLC). Both preparations were encapsulated into hard gelatin capsules, in combination with powdered omega-3 fatty acids. The daily dose of each formula was designed to contain the same amount of omega-3 fatty acids (346.5 mg).

For the study, eleven healthy volunteers (male and female, aged 18-25 years) were recruited and assigned, in a randomized fashion, to receive capsules containing 300 mg/day of Co Q-10 either in BF capsules or in PP capsules, for a period of one week. Blood samples were collected immediately prior to the first dose, and at 1, 2, 3, 4, 5, 6, 7, 8, 12 and 24 h after administration of the first dose treatment period. The dose continued for one week to study glutathione related plasma changes, including glutathione plasma level and glutathione peroxidase activity. After a 3-week washout, the same group of participants was given the second Co Q-10 formula at the same Co Q-10 dose and the protocol was repeated. Subjects were instructed to fast overnight prior to each study day where the initial Co Q-10 dose was administered (at 8 a.m.) and for the first 4 hours following administration of the first dose of each preparation. Subjects consumed a standardized low Co Q-10 lunch at 12 noon on the day of the initial dose.

Immediately after blood withdrawal, plasma was separated and stored at -70oC until assayed for concentration of Co Q-10 using HPLC method.
To compare the oral bioavailability of two preparations, the AUC from 0-24h (?g*mL/h), the maximum plasma concentration, Cmax (mg/mL) and time to maximum concentration, Tmax (h) were determined for each formula from the plasma Co Q-10 concentration-time profile, without inclusion of the basic AUC. Statistical comparisons of AUC0-24h, Cmax and Tmax between the two groups were performed using the non-parametric test for matched pairs (Wilcoxon-Sign Rank Test).

Plasma samples taken before each treatment and at the end of week 1 of each treatment were also tested for glutathione peroxidase activity (colorimetric assays) and plasma glutathione concentration (HPLC method).

RESULTS AND DISCUSSIONS

Three subjects were excluded as outliers because their baseline Co Q-10 levels before treatment were not comparable between the tests for two different formulas. The differences in baseline Co Q-10 were not related to the length of the washout period, since one outlier had higher baseline in the test before washout period. It is therefore possible that these subjects might have ingested high Co Q-10 foods during the last few days preceding baseline blood sampling.

BIOAVAILIABLITY COMPARISON

Cmax for BF and PP were 1.829 and 0.808 µg/mL, respectively. Cmax was significantly higher for BF than for PP (126% increase, p = 0.0391). This was consistent with the strong trend for higher AUC0-24h (26.345 µg/mLhr in BF form vs. 10.148 µg/mLhr in PP form, p = 0.07, BF:PP ratio as 2.60:1.00), and with the slight tendency for earlier Tmax (5.625 hour in BF form vs. 6.143 hour in PP form). 

Co Q-10 is synthesized in the human body. Without Co Q-10 consumption, the plasma Co Q-10 baseline is due to synthesis by the human body. In the study, baselines of BF and PP were very close (2.08 µg/mL in BF; 2.14 µg/mL in PP); the baselines were subtracted to reduce the influence from human synthesis and to focus on the effect of supplementation. Changes in the average plasma Co Q-10 levels after a single dose of BF vs. PP are illustrated in Figure 1.

The existence and functions of Co Q-10 in living organisms have a lot to do with bilayer membranes. Its major biological function is passing electrons across membranes. Due to its lipophilic property, Co Q-10 tends to stay inside the bilayer membrane. This membrane and its Co Q-10 complex seem to be a major repository of Co Q-10 in biological systems. The yeast cell membrane is a bilayer membrane, which is a very good storage place for Co Q-10. We can reasonably assume that the Bio-Foods' fermentation process transfers Co Q-10 from an aggregated powder into a water dispersible bilayer membrane complex. This might be the reason for increased human absorption of Bio-Foods Co Q-10 versa the pharmaceutical form.

The earlier tendency of maximum absorption peak in BF (5.6 hr) vs. in PP (6.1 hr) might indicate the absorption easiness of the BF yeast fermentation product, which may be due to the dispersion into a membrane complex of CoQ10 by nutritional yeast. Human absorption of nutrients has an upper limit. Absorption efficiency generally decreases with an increase in dosage. This phenomenon indicates that the human absorption system could be saturated by mega dose nutrients. If two forms of one nutrient have different absorption abilities, the absorption efficiency difference will appear larger if the dosage does not reach its saturation level. Mega dosage may increase the absolute difference over baseline so that it may be observed in a relatively small test group, but it may produce a lower difference in absorption efficiency between groups than would a small dosage. The dosage used in the study was 300 mg per person per day. This is a dose about 10 times higher than what is generally recommended for Co Q-10 products on the market. A larger comparative difference between the BF and PP groups could have been obtained if lower dosage had been employed.

GLUTATHIONE RELATED ANALYSIS

Caution should be used for the explanation of any data from human blood samples. Humans are not empty non-interactive containers, as would be an orange juice bottle if you put orange juice into it, or a milk bottle if you put milk into it. The human body has many regulatory systems to control body parameters and to adjust to different environments. A complete study and consideration of related factors is necessary to discover the truth under superficial results.
When someone gets a cold, the person's body temperature goes up with the increase of body metabolism velocity; the person's immune system is boosted to defend against the virus. Therefore the strengthening of the immune system in that particular case is not a good representation of the person's body condition, because it is due to a virus stress. When the person recovers from the cold, the body temperature cools down, and the immune system "cools" down also. The reduction of immune system strength in this case indicates the recovery of the person, and so the reduction is a good sign.
The human body has a defense system against oxidation stress as well, to prevent cancer and other inflammatory diseases. This system includes different components, named antioxidants, such as glutathione, vitamin E, vitamin C, Coenzyme Q-10, et al. Some of the components must be imported from the environment, like most of the vitamins. Some of the components can be produced by the body to control the oxidation level in the body according to the oxidation stress. Those antioxidants include glutathione and Co Q-10. In case of high oxidation stress, more glutathione will be produced, just like the immune system during a cold. In cases of low oxidation stress, the body produces less glutathione accordingly. There might be genetic differences in the antioxidant systems of different persons. Under the same level of oxidation stress, different persons will have different levels of glutathione in the body. For a particular person under generally the same healthy conditions, variation of body antioxidant levels, including glutathione and glutathione peroxidase (which helps glutathione to function), could be due to variations in oxidation stress.

Co Q-10 is a component of the oxidation defense system. Consumption of Co Q-10 can increase the body's Co Q-10 content, which will act against oxidation agents in the body, and reduce the oxidation stress in the body. Therefore, the body will reduce its glutathione production because of the reduction in oxidation stress. Further regulation of glutathione activity might be accomplished by regulation of glutathione peroxidase levels. A reduction of glutathione may trigger the increased production of glutathione peroxidase, and the responding degree may depend on the body's oxidation stress level. The lower the oxidation stress level, the less need to produce more glutathione peroxidase.

In our study, there was a moderate, nonsignificant tendency for reduced glutathione level after supplementation of Co Q-10 in both formulas. In both groups glutathione was reduced by a similar percentage (-24% in BF; -25% in PP) but the glutathione peroxidase activity did not show much of an increasing trend (+1% in BF; +14% in PP). This may be due to the fact that the CoQ10 level is very high in both groups and tends to be higher in the BF than in the PP test group (7.99 vs. 6.45 mg/L) which may have more effectively decreased oxidation stress.

CONCLUSIONS

The results demonstrated that Co Q-10 supplementation taken orally resulted in increased plasma Co Q-10 concentration. The increase in Bio-Foods formula test has a strong tendency to be more than that in the pharmaceutical formula test. The bioavailability of Bio-Foods formula was observed to be 2.60 times higher than that of pharmaceutical formula. Bio-Foods formula also resulted in a 126% higher maximum concentration and a 0.5 hour less maximum concentration induction time than did the pharmaceutical formula. The results indicated that Bio-Foods formula had better bioavailability than the pharmaceutical formula. The results of glutathione indicated that Bio-Foods formula was a stronger weapon against oxidation stress than was the pharmaceutical formula.


Najla Guthrie
Elzbieta M. Kurowska, Ph.D.
October 18, 2001

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