Unfortunately, the lack of definitions and accurate, meaningful testing methods led to confusion in the marketplace; not just to the consumer but also to the manufacturer seeking to provide the best and most efficacious product.

Today, a survey of the labels available for grape seed extract proved to be somewhat less confusing; the addition of the Supplement Facts Chart/Ingredient List has done much to bring some clarity to the category.

The goal of this document is to educate the reader and creator of grape seed labels to further the understanding and continuity.

Below is a list of terms that can and should appear on the Supplement Facts Chart/Ingredient List of grape seed extract.

Confusion starts from several terms that are basically synonyms being used sometimes interchangeably and sometimes with the implication they are different. For clarity the synonyms, all of which yield cyanidins upon heating in an acid media from which the term procyanidin originates, are listed here.

Synonyms:

Procyanidins

Proanthocyanidins

Procyanidolic oligomers

OPC

PCO

Leucoanthocyanins

Condensed tannins

pycnogenols (lower case only)

Other terms not defined here are often used in the labeling of grape seed products but are varied and can be considered marketing terms, not definitions.

Proanthocyanidins: Subset of the polyphenols; consisting of the polymers of flavan-3-ols (+)-catechin,

(-)-epicatechin, and (-)-epicatechin 3-O-gallate linked by C₄-C₈ or C₄-C₆ bonds. Some carry galloyl residues linked to the C-3 alcoholic function of the flavan-3-ol units.^,

pycnogenol: Term for proanthocyanidins used in much of the original research (should not be confused with the Trademarked name Pycnogenol^® which is composed of the same types of compounds derived from Pine Bark).

Polyphenols: Term that is more general than proanthocyanidins can be used when referring to the results of analytical work done to quantify the total oligomeric, monomeric and galloylated (having attached gallic acid units) components of grape seed extract.

The grape seed committee has agreed on some new terms that would give some clarity to the testing methods used to determine the total polyphenol content without adding too many unfamiliar terms or take up valuable label space. (For description of methods see Methods Section).

Polyphenols (GAE): Polyphenols quantified by the Folin-ciocalteau spectrophotometric method and calculated as gallic acid equivalents.

Polyphenols (VAN): Polyphenols quantified by the Vanillin method.

Polyphenols (GPC): Polyphenols quantified by Gel Permeation Chromatography.

Monomers (Monomeric): The sub-units of the procyanidin polymers.

Taking these definitions into account we can propose some acceptable labeling statements Typically, a label has two distinct parts that describe the grape seed product; the Supplement Facts Box and Ingredient List that is regulated by DSHEA, and the Description Section dedicated to the marketing of the contents.

Example A)

grape seed extract 40mg

This is the simplest way of accurately declaring the contents.

Example B)

80mg of grape seed extract (95 percent Proanthocyanidins)

This labeling attempts to provide more information about the grape seed extract, namely the percent of proanthocyanidins contained within the extract. However, the problem here is that there are no analytical methods for determining the proanthocyanidin content. It would be more accurate to list using terms for which a testing method exists, i.e. polyphenols. As grape seed extracts vary greatly in concentration it provides valuable information to include the percent of polyphenols. Sometimes this information is provided in the Description, if not then it is not necessary to also place it in the Ingredient Panel.

Example C)

80mg of grape seed extract (95 percent OPC’s)

In this case we can see that the label attempts the same effect as the one above but again uses a term, OPC, for which there exists no currently validated analytical method.

We propose the following as a solution to problems raised in Examples B & C:

80mg of grape seed extract (95 percent Polyphenols (GPC, GAE or VAN))

If the manufacturer wishes to describe the relationship between polyphenols and proanthocyanidins, the description panel would provide this opportunity.

Example D)

The Description Panel of this grape seed product describes it as standardized to 50% polyphenols. The Supplement Facts Box as listed above claims 30mg grape seed extract AND 15mg polyphenols. Such listing is confusing, as the product does not contain both ingredients.

One solution for this problem might be:

Example E)

A Grape Seed complex declares in the: Supplement Facts Box

Dietary Ingredients grapeseed l00mg proanthocyanidins 90mg grape skin and stem 19mg polyphenols 14mg

Among other ingredients.

The complex contains many plant extracts that can contain proanthocyanidins but this labeling does not make it clear if the proanthocyanidins are from the 100mg of grape seed or from another plant source. The same can be said of the polyphenol content. Polyphenols as we see from the above definition are a very general class or compounds that can be derived from several plant sources. Again, it is not clear here if there are in addition of the grape seed, the grape skin and stem or some other source.

One solution for this problem might be:

Example F)

grape seed extract 100mg.

Here, we can guess that the components of the grape seed extract are broken down as individual components. This fact is obscured by the addition of the whole extract to the panel.

All of these components can be derived from the grape seed. Therefore, it is hard to know from this label if the polyphenols, monomers (catechins and epicatechins) and other phenols (tested with reference to gallic acid) are from the grape seed or in addition to it.

Also confusing is the listing of total phenols as gallic acid equivalents without identifying the testing methodology of the other polyphenols and monomeric constituents.

One solution for this problem might be [indentation is accepted by FDA]:

Dietary Ingredients

Description Panel

The Description portion of the labeling is where most manufacturers choose to differentiate their product. Again, using examples, we can analyze the way the terms can be used effectively.

…a premium grape seed extract containing high levels of OPC’s and other polyphenolic compounds…

Each capsule contains 50mg grape seed extract, concentrated and standardized for a minimum of preferred 95% (47.5 mg) Polyphenols, including oligomeric proanthocyanidins.

Note: In this example the testing method for polyphenols is not listed, if it is not listed in the Supplement Facts, then it should be noted here.

…contains oligomeric proanthocyanidins (OPC’s) and other phenolic compounds. Grape seed extract is standardized to 50% polyphenols.

Again, the testing method for polyphenols is not listed, if it is not listed in the Supplement Facts then it should be noted here.

50mg of standardized grape seed extract supplying a minimum of 95% oligomeric proanthocyanidins.

This statement implies that the oligomeric proanthocyanidins have been quantified when there is currently no validated analytical method for the oligomeric proanthocyanidins.

Proanthocyanidins are measured by the amount of total Oligomeric Proanthocyanidin content or OPC. This product contains 95% OPC which consists of Monomers and Oligomers.

This statement again implies that the proanthocyanidins are measured as OPC, which is not precise and then attempts to qualify it by proclaiming the OPC consists of monomers and oligomers.

…combination of active monomers and oligomers proven… to be biologically beneficial. Grape seed, dried extract complex… 50mg Delivering 95% antioxidants from 65% Oligomeric Proanthocyanidins and 30% other active principles.

It is not accurate to claim 95% antioxidants (rather than polyphenols) in the marketing portion of the label when there are currently no defined methods that can accurately delineate what percent is due to the oligomers versus other principles.

A patented extract of the flavanol proanthocyanidins (PAC), prepared from the grape seeds…these are the most potent of the available proanthacyanidin extracts, since they have a higher total content of PAC (92 percent or greater).