PROANTHO

Top

	OPCs: What's the Story?
	Red Grapes vs. White Grapes
	Proantho

OPCs: What's the Story?

There is a growing number of products entering the marketplace which claim to be OPC-containing antioxidants, primarily extracts of grape seed and pine bark origin. Because there are no published and validated methods available to verify these claims, it is necessary for manufacturers and retailers to perform technical due diligence above and beyond what is generally required to qualify these products and verify that they carry accurate information on the label.

What are OPCs?

OPC is an acronym for oligomeric proanthocyanidin. According to Webster’s Dictionary, oligomer means polymer or polymer intermediate containing very few structural units. The Greek define oligo as few. Oligomeric proanthocyanidin or proanthocyanidins, often used interchangeable, are clusters of phenolic compounds built from single monomer units called catechin and epi-catechin. Although the definition of oligomeric varies somewhat, dimers (two units), trimers (three units) and sometimes up to heptamers (seven units) are generally referred to as oligomeric while larger complexes are referred to as polymeric and/or tannins. In the nutritional supplement industry, there is no clear agreement on the division between oligomers (OPCs) and polymers and/or tannins.

Additionally, it must be noted that it is not clearly agreed upon what size oligomer or polymer is responsible for what degree of biological activity. Some sources agree that it is only the dimers and trimers (oligomers less than four units) that show health benefits while others insist that larger polymers and even monomers (the single units) can be linked to antioxidant activity. More research must be performed to determine specifically what procyanidin oligomers or polymers and monomers are efficacious for antioxidant activity and at what levels.

A wide variety of extraction techniques are employed by grape seed and pine bark extract manufacturers. Depending on the extraction technique used, the procyanidin compounds in pine bark and grape seed extracts can be present in different sizes or degrees of polymerization. Some manufacturers specifically target smaller oligomers while others target a broad range of monomers, oligomers and polymers. Some manufacturers desire a small percent of monomers (i.e. catechins) in their final extract while others include a higher percentage of monomers.

How can we qualify OPC content?

An ideal analytical method would be one capable of quantifying the amount in milligrams or percent of each size oligomer and/or polymer present in an extract (e.g. % monomers, dimers, trimers, etc.). These types of analytical data would allow manufacturers to verify the claims made on their products. Unfortunately we know of no available method which can provide this information. A stable supply of characterized reference standards is needed to develop and continually provide such analysis. Monomer standards are available but oligomer/polymer standards are not. In the absence of suitable quantitative analysis for each category of oligomer, semi-quantitative analysis is currently in use.

Recently, Industrial Laboratories requested the cooperation of Hauser and Alpha Chemical & Biomedical Laboratories, as a peer review group, to evaluate the available semi-quantitative analytical methods in order to establish the most reliable interim method to characterize the composition of extracts containing OPCs. After careful review and inter-laboratory performance, evaluation, employing identical reference materials from five different sources, the peer review group chose two methods that demonstrate both reproducibility and robustness. Although they are incapable of verifying % OPC label claims, the two recommended methods listed below can be used to qualify raw materials for consistency and to establish specifications for vendor and batch record documentation.

A) The Porter Method (PVU)

The Porter method measures the procyanidin oligomers/polymers as the absorbance of a 1% w/v solution of methanol soluble sample material at 550 nm. Monomers are not included in the measurement and the degree of polymerization is not differentiated. Results are reported as Porter Value Units (PVUs), not as percent, which correlates to the procyanidin content. Absorbance generally increases with average phenolic content. On a molar basis, hexamers will have higher PVUs than dimers. Therefore, if a grape seed extract is comprised of primarily larger polymers, it will have a higher PVU than an extract comprised of the same molar concentration of dimers. In our experience, grape seed and pine bark extracts have ranged from 25 to 325 PVUs.

B) Percent Monomers as Catechin and Epi-catechin

Validated HPLC methods and reference standards are available (from Sigma Chemical, for example) to quantify the percent monomers in sample materials.

Although not ideal, we believe that the Porter Method and Percent Monomer information provide a suitable interim step to characterize procyanidin products. This approach gives manufacturers information to evaluate consistency of extracts as well as information to aid in characterizing composition of these products. To more completely assess product quality, it is necessary to perform a number of different assays and thoroughly analyze all the data against what is represented to be the targets in the extraction process. Again, some vendors intentionally target smaller oligomers while others target a broader mix of oligomers and polymers. Performing additional assays on pine bark and grape seed extracts such as solubility and total polyphenols will provide additional information necessary to more accurately qualify the extracts. Once this qualification process is complete the PVU and % monomer data can be used routinely to verify consistency.

These methods in standard operating procedure (SOP) form are available from Industrial Labs directly as well as through AHPA. Availability of validated methods for botanical products satisfies one of Industrial Labs primary objectives which is to ensure consistency in testing between all laboratories.

It must be understood that the analytical methods listed above are not capable of assessing product quality in terms of biological activity. More clinical research is necessary to determine specifically which compounds are efficacious and bioavailable. Methods must be developed to specifically measure this activity.

Some commonly asked questions about OPC product testing : 

1. What about the Procyanidolic Value?

   The procyanidolic value is reported by the Bate-Smith procedure. This procedure is similar to the Porter method in that it measures the procyanidin oligomers/polymers as the absorbance of a 1% solution of sample. The results are also reported as a value and not as a percent. We have found the Bate-Smith method to be highly irreproducible and, as such, Industrial Labs will not perform this test.
    

2. Is a high PVU all that I should consider when evaluating an extract?

   No. As was stated above, it is important to know the desired composition of extract for your product formulation and to take necessary steps to acquire the data that can best verify this composition and subsequently verify the consistency in its production. These steps will include acquiring information about the extraction targets as well as analytical data in addition to PVU.
    

3. If a manufacturer tells me the extraction technique that was used, can I make % OPC claims?

   First it must be clear how OPC is being defined. If a manufacturer has performed extensive research on the composition of their product and is willing to share that knowledge with another laboratory and if the methods used to make the initial claim are valid methods it may be possible to verify OPC claims. It must be noted, however, that most manufacturers hold this information confidential.
    

4. What does % polyphenols and % flavanols mean?

   Flavanols are specific types of polyphenols. OPCs are specific types of flavanols. Polyphenols are compounds comprised of multiple phenolic groups. Polyphenols in general can be measured by a number of different methods, the most common of which is the Folin-Cioclteau method. This method reports results in gallic acid equivalents. Most of these methods report results in the form of equivalence such as gallic acid or catechin. This equivalence data is necessary because it is impossible to measure phenolic compounds in the group; therefore, a representative standard must be chosen.

Provided to NUTRISANA NATURALS by The Industrial Laboratories Company, Inc. of Denver, Colorado. 

Back to the Top
 
 

Red vs. White Grapes

As a source of Antioxidants

By Dr. James Baker M.D., C.M., F.R.C.S.( C ).

The question has been asked, "Is the antioxidant derived from red grapes more potent than the antioxidant derived from green/white grapes?"

This topic was discussed by Professor Emeritus Jacques Masquelier in the book "OPC in Practice" by Bert Schwitters, in collaboration with Dr. Masquelier. On page 22, Dr Masquelier is quoted as saying,

"It is always a red pigment (anthocyanins) which is derived from these colorless substances (proanthocyanidins). This transformation into anthocyanins can be produced in the laboratory through a chemical process. It is produced spontaneously in nature in the autumn when the leaves of certain trees turn red. The differences between these pigments are fundamental as regards bio-availability and the effects on the human organism. These two notions are related, because if there is no bio-availability, there will be no physiological reaction".

Schwitters continues with his question:

"Does OPC retain its biological activity when it turns into red pigment? Masquelier's reply: 'The anthocyanins are NOT interesting from a medical point of view or for their capillary resistance. Anthocyanins are highly fragile substances, in particular when they do not exist in an acidic environment….In wine, that has an acidity of 2.5, the anthocyanins are totally stable, which is why red wine always stays red. The acidity of our blood, which is close to neutral, is totally incompatible with the existence of anthocyanins. You can absorb anthocyanins, but they destroy themselves. They cannot exist in a neutral environment and even less so in an alkaline environment'".

So what does all this mean? First of all, the coloration of red or purple grape seed extracts is produced by two different factors: 

 

	The presence of flavons leached out from the skins, and,
	The presence of anthocyanidins (red color) as a result of conversion from proanthocyanidins (colorless) in an acid environment.

The fermentation in the wine making process provides the acid environment for this conversion to occur. Flavons are inferior antioxidants, so their presence does not contribute appreciably to the antioxidant potency of the extract. The amount of proanthocyanidins in the grape seed extract determines the antioxidant potency. 

In fact, in almost all cases, the Porter value is higher when the source of the grape seed extract is the green/white grape. With the leading independent laboratories now using the Porter Assay to assess the concentration of cyanidins in grape seed extracts, and, since we believe that proanthocyanidins are the bio-effective antioxidants which produce the desired biological effect, it would seem logical to use the source which consistently produces the highest yield of proanthocyanidins, namely the green grape.

Laboratory analyses have demonstrated that green grapes produce an antioxidant with higher Porter Values (higher cyanidolic content) than those produced from red grapes. This fact explains Omega's preference for their predominantly green grape source. 

Back to the Top
 

Proantho Grape Seed Extract

Currently the nutritional industry's most potent Super-antioxidant & a most important supplement to good health.

Nutrisana PROANTHO  is an important bioflavanoid has been extracted by a specialized process researched and developed in Canada, using selected Vitis Vinifera seeds only, from grapes grown in the United States. This product is a natural substance generally known as cyanidin, a sub-class of flavanoid, found in most plants. Cyanidins and cyanins have been used extensively for decades in Europe and Asia. There are a variety of antioxidant products today that are marketed as OPCs, proanthocyanins, "standardized extracts", that are extracted from a combination of many varieties of grape seeds and skins. 

Antioxidants are important supplements required in our diet to neutralize, scavenge, and eliminate from the body, free radical molecules before they can do serious damage to our tissues and organs. Free radicals are unstable molecules which attack DNA and mitochondria, the basic building blocks of all tissues, thereby impairing the functional health of membranes and organs. This damage impedes the replication of healthy cellular material throughout the body and leads to premature aging. Free radicals are implicated in the causation of over 60 degenerative diseases.

Consistent use of a super-antioxidant such as PROANTHO can assist the natural enzymatic repair system of the cells which control the replication of the cellular matrix throughout the body, even to the point of achieving reversal of many symptoms that have accrued over time. 

PROANTHO has a special property that allows it to cross the 'blood-brain' barrier. This barrier is a natural protection for extremely sensitive brain tissues that could be damaged by potentially hostile elements carried by our cardiovascular system. PROANTHO passes this barrier, scavenges free radicals within brain tissue, improving brain function.

PROANTHO acts as a protector against exposure to ultra-violet or gamma radiation, pesticides, preservatives, chemical pollution and heavy metals. All of which produce free radicals in our bodies.

PROANTHO is totally assimilated into the body within seconds, absorbed and at work very quickly. It enhances the effectiveness of other antioxidants such as vitamins A, C and E. Because it is many times more powerful as a free radical scavenger, it frees them up to perform their other functions.

PROANTHO inhibits the formation of certain enzymes that break down collagen and are the direct or indirect cause of allergies and inflammation. This inhibition prevents the production of histamine and thereby reduces allergic response. For example, antioxidants have been used extensively in Finland to control hay fever.

PROANTHO improves the collagen matrix of blood vessels, thereby reducing or preventing leakage of fluid which (leads to peripheral edema) thus improving circulation. In effect, this enables the capillaries to carry more oxygenated red corpuscles to tissues, expediting soft tissue healing. Improved circulation is especially valuable to diabetics, arthritics, stroke victims, smokers, women taking oral contraceptives and people with swollen edematous extremities from hypertension, heart failure or varicose veins.

A suggested rate of consumption is one milligram of PROANTHO for every pound of body weight for ten to fifteen days, then reduce the amount, according to your lifestyle or exposure to stress or other forms of pollution. A maintenance rate of consumption would be between 60mg and 120mg per day taken with meals in the morning and evening.

In Europe, where antioxidants have been used for several decades in the pharmaceutical industry, there is a very large number of reports indicating that the consistent use of antioxidants has been shown to:

	Reduce the rate of aging
	Reduce wrinkling of the skin
	Aid in resistance to bruising
	Reduce the risk of cancer
	Reduce inflammation
	Improve prostate function
	Improve peripheral and central circulation
	Improve joint flexibility
	Enhance energy
	Reduce mental aging
	Reduce the risk of heart disease
	Reduce the risk of stroke
	Enhance the immune system
	Reduce fatigue
	Subdue allergic response
	Reduce frequency and severity of colds
	Reduce varicose veins
	Improve visual acuity
	Repair artery and vascular lining
	Enhance the benefits of other vitamins
	…and provide relief to numerous other minor ailments

Back to the Top

---

All material and information presented by Nutrisana.com is intended to be used for educational purposes only. The statements made about products have not been evaluated by the Food and Drug Administration (U.S.). They are not intended to diagnose, treat, cure or prevent any condition or disease. Please consult with your own physician or health care practitioner regarding the suggestions and recommendations made at Nutrisana.com.

Copyright © 1998-2000 Nutrisana International inc., all rights reserved