by Eric Brand

Today, I am uploading a two-part series that is aimed at discussing concentration ratios. This first blog is aimed at giving some general background information. The next blog will go into greater detail about concentration ratios in terms of general granule products, tablets and other concentrated extracts, and finally I'll write some more material that is specific to Blue Poppy's products. A bit of general background information is critical to understand the overall field of concentrated extracts, and then I can elaborate in greater detail about the specific methods that we use to create our outstanding products, including our exciting upcoming granule and tablet lines (our tablets are called "caplets," capsule-shaped tablets). There is a lot to say, so I am splitting it up into several blogs.

Understanding the relationship of raw herbs to the finished product is important when using granule extracts. The term “concentration ratio” is used to express the ratio between the source materials (the raw herbs) and the finished product; this is often abbreviated as S : P, which stands for the ratio between source and product. For example, a ratio of 5:1 implies that five kilograms of dried crude medicinals (“raw herbs”) is concentrated to one kilogram of final product. This is also sometimes referred to in the herbal pharmaceutical industry as a 20% yield.

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What Concentration Ratios Can Tell Us and What They Cannot

Concentration ratios are inherently useful because they allow us to calculate dosage in a meaningful, mathematical accurate fashion. A practitioner’s greatest ally is a clearly-labeled, openly expressed concentration ratio, because this information allows the practitioner to be informed about the amount of medicine that they are prescribing to their patient. Practitioners study dosage in the context of raw herbs, and most Chinese medical prescriptions are based the amount of raw herbs that would be prescribed in a typical “pack” (ji) for use as a decoction. Concentration ratios are the bridge to understanding how much of a concentrated extract should be used to achieve an effect equivalent to a raw herb decoction, which remains the basic standard of care in professional Chinese medicine worldwide.

While concentration ratios offer the most direct way of determining a target dose when using granules, it should be noted that there are many additional factors that must be considered beyond simple mathematical equivalence. For example, the cooking time, water quantity, fillers, solubility of constituents, and other factors influence the concentration that can be achieved with any given medicinal when making single-herb extracts. Concentration ratios tell us a lot about the potency of any given product, but ultimately the situation is more complex than the concentration ratio alone.

Standardized Extracts and Liquid Extracts

Within the broader herbal medicine industry outside of TCM, we find several examples of different methods of calculating concentration ratios. Beyond the source-to-product concentration ratios that are used for granule extracts and pills in Chinese medicine, we also see products on the supermarket shelf that have “concentration ratios” that are based on isolated constituents, and concentration ratios based on liquid extracts.

This blog series is focused on granules and other concentrated dry extracts such as tablets and capsules. Nearly all of the granule and pill products used in Chinese medicine are full-spectrum water extracts. Thus, for the clinical application of granules and pills, the only relevant approach to concentration ratios is a discussion of the source-to-product ratio mentioned above. Nonetheless, readers should be aware of the other methods of calculating extraction ratios that show up in the dietary supplement industry.

Outside of the world of professional Chinese medicine, one prominent method of calculating concentration ratios utilizes a calculation based on isolated constituents. These extracts are often called “standardized extracts,” and their “concentration ratio” is calculated based on the amount of raw material that it would take to yield an equivalent amount of a certain therapeutic marker chemical. Standardized extracts are often made by mixing a full-spectrum extract with a fractional isolate (relatively pure active constituents that have been isolated from a plant source with the use of solvents and modern chemical techniques).

The use of fractional isolates is particularly common for items such as ginkgo biloba, which has relatively clear active constituents that require relatively high concentrations for an appropriate therapeutic effect. For example, ginkgo biloba extracts are often produced with organic solvents and standardized to 50:1 based on flavone glycosides and terpine lactones. Fractional isolates are more akin to pharmaceutical preparations than traditional herbal products, so they are generally not used within the TCM industry.

Some common Chinese medicinals such as ginseng are occasionally sold in standardized extracts based on ginsenosides, but the standardized extracts found in the supplement industry are generally not used extensively by TCM practitioners. By contrast, the ginseng extracts that TCM practitioners use are often tested to ensure minimum levels of naturally-occurring ginsenosides, but the ginsenosides are not extracted with organic solvents and re-introduced to create a standardized extract. When ginseng is made into a standardized extract, usually large amounts of ginsenosides are extracted from the inexpensive leaves or rootlets with organic solvents. These isolated ginsenosides are then added in to a poor-quality extract of the root body so that the appropriate level of ginsenosides can be achieved. Most TCM practitioners do not use these products, instead preferring to purchase full-spectrum extracts of the root body (the traditional form of ginseng). The item preferred by the TCM community thus preserves the spectrum of constituents that would naturally come out in a traditional water decoction.

While Chinese medical practitioners generally do not use standardized extracts clinically, most granule extracts used in TCM have been analyzed to assess their levels of marker compounds. Marker compounds, such as ginsenosides, are used to measure authenticity and potency in full-spectrum extracts. Here, the marker compounds are used as a reference rather than being the target of the extraction procedure, and the main goal is to simply ensure that the starting materials are of adequate potency for use.

Beyond the world of granules vs. standardized extracts, we also find liquid extract products on the market that discuss concentration ratios. Confusingly, the concentration ratios of liquid extracts are also often expressed by numbers such as 8:1 or 5:1, making the ratio seem similar to that of granule extracts. While there are a number of ways that this ratio can be calculated when taking about liquid concentrates, sometimes the ratio simply reflects the degree to which the original decoction has been reduced by evaporation.

When it comes to liquid concentrates, the most meaningful expression of concentration reflects the amount of raw herbs per milliliter of finished product. Most methods of manufacturing liquid concentrates in the TCM field max out at about one gram of crude herb per milliliter (1g/ml, or about 30 grams per fluid ounce). Higher concentrations are difficult to achieve because the liquid becomes supersaturated and solids begin to fall out of suspension.

Check back to continue on to section two of this blog, which will really be diving into the meat on this topic.